Article

Comparison of freshwater and marine performances of all-female diploid and triploid Atlantic salmon (Salmo salar L.)

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Abstract

The performance of all-female diploid (AF2N) and triploid (AF3N) Atlantic salmon were compared in fresh water, under commercial production conditions in 1995 and 1996 year classes. The performance of the 1996 year class was also assessed for 14 months in a commercial sea farm. Freshwater mortality was higher in the triploid groups. The majority of losses occurred in the early stages of egg development and during the first feeding period, when the incidence of non-feeding fry was consistently higher. In growth studies, although diploid fry were significantly heavier during first feeding there were no significant differences in weight between groups some 8 months after fertilization or in presmolt growth periods from February to April in 1996 and 1997. Smolting rates were high (range 93.5–95.3%) and the incidence of deformities was low (< 1%) in both groups. Marine survival was lower in the triploid group, largely as a consequence of higher losses sustained during a period of chronic stress, when triploid losses were 9% higher. Growth patterns were similar for the first 11 months in sea water. Although graded triploid salmon were heavier in January 1998 (AF3N 1.62 ± 0.033 kg, AF2N 1.46 ± 0.36 kg, P < 0.05), when the fish were harvested in May 1998 diploid salmon were significantly heavier than triploid salmon although there was no significant difference in weights after evisceration (AF3N 2.40 kg ± 0.04 AF2N 2.49 kg ±0.03). The increase in weight of the diploids between winter and harvest reflects the growth spurt that occurs in maturing fish in the spring. Overall yields of triploid salmon in salt water were lower as a result of inferior survival.

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... There have been significant developments in salmon aquaculture, i.e. in terms of better feeds and optimized production regimes, since the last comprehensive study on the application of triploid salmon under commercial production conditions (Cotter et al., 2002). In addition, the last decade has witnessed an increased awareness in the welfare of farmed fish. ...
... However, condition factor was consistently lower in triploids compared to diploids. Reports of triploid growth performance in Atlantic salmon are inconsistent between and within studies with triploid growth reported to be inferior (Friars et al., 2001;McGeachy et al.,1995), equal (Sacobie et al., 2011), or superior (O'Flynn et al., 1997Oppedal et al., 2003) to diploid counterparts with performance depending on life stage (Cotter et al., 2002;Leclercq et al., 2011), year class (Cotter et al., 2002;O'Flynn et al., 1997), rearing method (Fraser et al., 2012c;in press), or sex (Taylor et al., 2013). Our results suggest that triploid performance is impaired during the marine phase (i.e. ...
... However, condition factor was consistently lower in triploids compared to diploids. Reports of triploid growth performance in Atlantic salmon are inconsistent between and within studies with triploid growth reported to be inferior (Friars et al., 2001;McGeachy et al.,1995), equal (Sacobie et al., 2011), or superior (O'Flynn et al., 1997Oppedal et al., 2003) to diploid counterparts with performance depending on life stage (Cotter et al., 2002;Leclercq et al., 2011), year class (Cotter et al., 2002;O'Flynn et al., 1997), rearing method (Fraser et al., 2012c;in press), or sex (Taylor et al., 2013). Our results suggest that triploid performance is impaired during the marine phase (i.e. ...
Article
The study objective was to compare the effect of ploidy on growth, downgrading, discards, and fish quality at slaughter, the prevalence of skeletal deformities (external examination: spinal, jaw and operculum; radiology: spinal), and heart morphology from a large production of diploid and triploid Atlantic salmon (Salmo salar) reared in triplicate (n = 20 000 ploidy− 1). Triploids were 15% heavier and 7% longer than diploids at seawater transfer but diploids were 10% heavier and 1% longer than triploids at slaughter. Triploidy had no effect on gutted mass for each quality classification but significantly reduced the percentage of fish classified as superior whilst increasing the amount of production and discard quality (mean % ± SE (n = 3 ploidy− 1): superior, 89.6 ± 1.8 vs 83.7 ± 1.4; production, 2.4 ± 0.5 vs 6.5 ± 0.1; discards, 0.9 ± 0.2 vs 2.1 ± 0.2 for diploids and triploids, respectively). As a result, less money was received per triploid fish compared to diploids (the average price fish− 1 cage− 1 (n = 3 ploidy− 1) ranged between 62.3–81.1 and 63.5–67.4 Norwegian kroner for diploids and triploids, respectively). Total discards and downgrading were increased by triploidy due to deformities and triploids also had more fish discarded due to “small fish” compared to diploids. Radiography demonstrated triploids had more fish with one or more deformed vertebrae (mean %, 22.0 vs 42.7 and 24.4 vs 48.9 in diploid and triploid, parr and post-smolts, respectively). Diploid seawater mortality was significantly lower than triploids (1.2–1.5 and 1.8–2.2% cage-1, respectively). Triploid food conversion ratios (FCR) and specific growth rates (SGR) were inferior to diploids during the latter half of seawater phase (range: FCR, 1.36–1.47 and 1.55–1.67; SGR, 0.49–0.53 and 0.44–0.46 for diploids and triploids, respectively). Triploids had a lower angle of the bulbus arteriosus at slaughter (mean angle ± SE (n = 3 ploidy− 1): 46.5 ± 0.1 and 39.1 ± 1.3 in diploids and triploids, respectively). There was no effect of triploidy on ventricle mass, ventricle roundness, or the compact:spongy myocardium ratio. Sex had a significant effect on body length and ventricle mass with males 3% longer and having hearts 5.8% heavier than females. Overall the present data would suggest triploids are suitable for culture purposes but at a higher economic cost to the producer. In addition, future work should focus on reducing the prevalence of deformities in order to improve triploid quality and welfare.
... Fraser et al. [43], +8.6%). In addition, the current findings also support performance studies where triploids were heavier in freshwater and early seawater stages but lost their weight advantage by harvest [33,35,39,45,56,75]. As previous studies in triploid Atlantic salmon have reported a negative link between high temperatures (≥12°C) and feed intake and growth [35,36], it could be suggested that the high water temperature experienced in the current study from July to October 2017 (12.9-15.4°C), ...
... In terms of growth rate, TGC in triploids was lower than diploids at both smolt and harvest which is indicative of a slower growth rate in triploids. This finding agrees with previous studies [75,77,78] but contrasts with studies showing improved freshwater growth [28,45,55]. Knowing that triploids were heavier than diploids at vaccination suggesting faster growth rate from first feeding, reduced TGC in triploids may be the result of high temperatures (14-16°C) experienced both pre-and post-vaccination. ...
... This is supported by Sambraus et al. [35] whose study found that increased temperatures (> 15°C) negatively affected feed intake in triploids and subsequently reduced growth. In seawater, lower triploid TGC is supported by previous studies where the early growth advantage experienced by triploids is lost [45,55,68,75,79]. With few studies showing that triploid growth can be sustained at a higher rate through to harvest [28,33], it is recommended that further work be undertaken to fully optimise the rearing of triploids in seawater to achieve maximum growth potential. ...
Article
Full-text available
While triploid Atlantic salmon represent a practical and affordable solution to the issues associated with sexual maturation in the salmonid aquaculture industry, empirical evidence suggests triploids are more susceptible to disease and vaccine side-effects than diploids. With vaccination now part of routine husbandry, it is essential their response be studied to confirm their suitability for commercial production. This study tested the response of triploid and diploid Atlantic salmon to vaccination with commercially available vaccines. Triploid and diploid Atlantic salmon siblings were injected with one of three commercial vaccines (or sham-vaccinated) and monitored for performance throughout a commercial production cycle. Sampling at smolt and harvest was undertaken along with individual weight and length assessments through the cycle. Antibody response to Aeromonas salmonicida vaccination was similar in both ploidy, with a positive response in vaccine-injected fish. For both adhesions and melanin, analysis found that higher scores were more likely to occur as the anticipated severity of the vaccine increased. In addition, for adhesion scores at smolt and melanin scores at smolt and harvest, triploids were statistically more likely to exhibit high scores than diploids. Triploids maintained a significantly higher body weight during freshwater and until 11 months post-seawater transfer, with diploids weighing significantly more at harvest. Growth, represented by thermal growth coefficient (TGC), decreased in both ploidy as the severity of adhesions increased, and regression patterns did not differ significantly between ploidy. Vertebral deformity prevalence was consistently higher in triploids (smolt 12.3 ± 4.5%; harvest 34.9 ± 5.9%) than diploids (smolt 0.8 ± 0.5%; harvest 15.9 ± 1.9%), with no significant difference between vaccine groups in each ploidy. This study demonstrates that triploids respond as well to vaccination as diploids and provides further supporting evidence of triploid robustness for commercial aquaculture.
... As diploid females reached sexual maturity, triploid Atlantic salmon tended to exhibit lower condition factor (weight-at-length) (Benfey and Sutterlin, 1984b). Mortality in the freshwater phase of the life cycle was higher in triploid than in diploid Atlantic salmon, especially during egg development and first feeding (Cotter et al., 2002), when triploid fry were slower to disperse and feed (Jungalwalla, 1991;McGeachy et al., 1991). Most authors have observed similar freshwater survival among diploid and triploid Atlantic salmon (Galbreath et al., 1994;Johnstone et al., 1991;Jungalwalla, 1991;O'Flynn et al., 1997). ...
... Most authors have observed similar freshwater survival among diploid and triploid Atlantic salmon (Galbreath et al., 1994;Johnstone et al., 1991;Jungalwalla, 1991;O'Flynn et al., 1997). Growth rate in freshwater was similar, smolting rate was similar, but marine survival was lower in triploid than in diploid Atlantic salmon (Johnstone et al., 1991;Jungalwalla, 1991;McGeachy et al., 1996;O'Flynn et al., 1997), in at least one study (Cotter et al., 2002) as a consequence of higher losses sustained during a period of chronic stress imposed by parasites, high temperature and low dissolved oxygen levels. While some studies have suggested that chronic stress due to high water temperature caused higher mortalities in triploid salmonids (Ojolock et al., 1995;Oliva-Teles and Kaushik, 1990;Quillet and Gaignon, 1990), others suggested that stress response was similar among diploid and triploid Atlantic salmon (Biron and Benfey, 1994;Benfey and Biron, 2000;Sadler et al., 2000aSadler et al., , 2000b. ...
... While some studies have suggested that chronic stress due to high water temperature caused higher mortalities in triploid salmonids (Ojolock et al., 1995;Oliva-Teles and Kaushik, 1990;Quillet and Gaignon, 1990), others suggested that stress response was similar among diploid and triploid Atlantic salmon (Biron and Benfey, 1994;Benfey and Biron, 2000;Sadler et al., 2000aSadler et al., , 2000b. Marine growth of diploid and triploid Atlantic salmon was similar until the approach of sexual maturation, when diploids exhibited a growth spurt (Cotter et al., 2002). The return rate of triploid Atlantic salmon released into rivers or the west coast of Ireland was less than that for diploid salmon (Cotter et al., 2000;Wilkins et al., 2001), although the return of some triploids suggested that return was not inextricably linked to reproduction. ...
... In order to implement successful triploid production on a commercial scale, their performance in growth, health and overall robustness must be at least equal, or higher, to that of diploids (Oppedal et al., 2003). However there are reports of higher mortality in early stages in freshwater (Cotter et al., 2002;McGeachy et al., 1995;O'Flynn et al., 1997) and at seawater transfer (Galbreath and Thorgaard, 1995). Additionally an increased occurrence of cataracts (Leclercq et al., 2011;Oppedal et al., 2003;Wall and Richards, 1992) and higher deformities in triploid salmonids have largely prevented the uptake of triploidy within the European sector Jungalwalla, 1991;Kacem et al., 2004;Lijalad and Powell, 2009;Sadler et al., 2001;Sutterlin et al., 1987). ...
... Mortality during both freshwater and seawater rearing was generally low and did not differ between ploidy. This is in contrast to previous studies reporting higher triploid mortality (Cotter et al., 2002;McGeachy et al., 1995;O'Flynn et al., 1997). Increased triploid mortality, particular at seawater transfer in previous studies may relate to incorrect transfer times (Galbreath and Thorgaard, 1995) or differences in the smolt rate between ploidy (Taylor et al., 2012). ...
... Triploids grew significantly faster than diploids throughout freshwater rearing (SGR wt 1.34 vs. 1.27% day −1 ) consistent with other studies (Leclercq et al., 2011;O'Flynn et al., 1997;Oppedal et al., 2003), but contrary to studies showing similar or slower growth of triploids in freshwater (Cotter et al., 2002;McGeachy et al., 1995;Shrimpton et al., 2007). Following seawater transfer, triploids initially maintained a higher growth rate and body weight than diploids for eight months but over time SGR wt declined to 0.98% day −1 whereas diploids reduced to lesser degree of 1.07% day −1 . ...
Article
This study examined performance traits between diploid and triploid siblings within 44 full-sib families (produced by 15 sires and 44 dams) under commercial rearing conditions from first feeding to harvest. Survival did not differ between ploidy levels throughout the production cycle. Triploids grew faster (+30%) in freshwater, but slower during the seawater phase (−7.5%), although overall growth was comparable between ploidy levels (SGR 1.17 vs. 1.18% day−1). Triploids showed no visual deformity in freshwater but a significantly increased prevalence in seawater, mainly evident as jaw malformations and radiological deformed vertebrae. However, severity of deformities was considerably lower than in previous studies, as was the occurrence of cataracts. Using fixed effect linear models the combined effect of deformity and cataract only explained 50% of reduced growth performance, suggesting that other factors were also contributing to reduced performance in triploids. These differences could be due to different nutritional requirements and environmental tolerances in triploids. Family differences were obtained for growth traits (weight and length). Family ranking for production traits was also consistent between diploid and triploid siblings. Harvest quality grading was high (>99% superior) and flesh quality was comparable between ploidy levels, although triploids did have significantly higher PUFA levels at harvest. The study indicates the potential for superior triploid growth, and in conjunction with development of triploid specific diets may be sufficient in order to establish viable triploid salmon aquaculture.
... As diploid females reached sexual maturity, triploid Atlantic salmon tended to exhibit lower condition factor (weight-at-length) (Benfey and Sutterlin, 1984b). Mortality in the freshwater phase of the life cycle was higher in triploid than in diploid Atlantic salmon, especially during egg development and first feeding (Cotter et al., 2002), when triploid fry were slower to disperse and feed (Jungalwalla, 1991;McGeachy et al., 1991). Most authors have observed similar freshwater survival among diploid and triploid Atlantic salmon (Galbreath et al., 1994;Johnstone et al., 1991;Jungalwalla, 1991;O'Flynn et al., 1997). ...
... Most authors have observed similar freshwater survival among diploid and triploid Atlantic salmon (Galbreath et al., 1994;Johnstone et al., 1991;Jungalwalla, 1991;O'Flynn et al., 1997). Growth rate in freshwater was similar, smolting rate was similar, but marine survival was lower in triploid than in diploid Atlantic salmon (Johnstone et al., 1991;Jungalwalla, 1991;McGeachy et al., 1996;O'Flynn et al., 1997), in at least one study (Cotter et al., 2002) as a consequence of higher losses sustained during a period of chronic stress imposed by parasites, high temperature and low dissolved oxygen levels. While some studies have suggested that chronic stress due to high water temperature caused higher mortalities in triploid salmonids (Ojolock et al., 1995;Oliva-Teles and Kaushik, 1990;Quillet and Gaignon, 1990), others suggested that stress response was similar among diploid and triploid Atlantic salmon (Biron and Benfey, 1994;Benfey and Biron, 2000;Sadler et al., 2000aSadler et al., , 2000b. ...
... While some studies have suggested that chronic stress due to high water temperature caused higher mortalities in triploid salmonids (Ojolock et al., 1995;Oliva-Teles and Kaushik, 1990;Quillet and Gaignon, 1990), others suggested that stress response was similar among diploid and triploid Atlantic salmon (Biron and Benfey, 1994;Benfey and Biron, 2000;Sadler et al., 2000aSadler et al., , 2000b. Marine growth of diploid and triploid Atlantic salmon was similar until the approach of sexual maturation, when diploids exhibited a growth spurt (Cotter et al., 2002). The return rate of triploid Atlantic salmon released into rivers or the west coast of Ireland was less than that for diploid salmon (Cotter et al., 2000;Wilkins et al., 2001), although the return of some triploids suggested that return was not inextricably linked to reproduction. ...
... The mortality rate was higher in triploids than in diploids during the first half of the period on different experimental feeds, up to~35 g size. This result is in accordance with the findings of Cotter et al. (2002), who found higher mortalities in all-female triploids throughout the freshwater period, and Johnstone et al. (1991), who recorded higher survival of all-female diploids during the first 7 months of feeding. However, several studies have shown equal survival between diploids and triploids in the period from first feeding to seawater transfer (McGeachy et al. 1995;O'Flynn et al. 1997;). ...
... Faster growth of triploid compared to diploid Atlantic salmon in fresh water as observed in the present study was also observed in the studies of and Leclercq et al. (2011). However, older publications have shown equal (McGeachy et al. 1995;O'Flynn et al. 1997) or slower growth (Cotter et al. 2002) in triploids compared with diploid Atlantic salmon in fresh water. The faster growth in triploids compared to diploids in fresh water in the more recent publications may be due to improvements in the quality of commercial salmon feeds and/or production methods. ...
... Also, Galbreath & Thorgaard (1995) found equally low specific growth rates in diploid (0.52) and triploid (0.49) all-female Atlantic salmon during their first year in sea water. However, there seems to be some dimorphism in appetite (Oppedal et al. 2003) and growth pattern (Cotter et al. 2002) between diploid and triploid Atlantic salmon during the marine phase, which may be related to different responses to season and/or water temperature. ...
Article
Triplicate groups of triploid and diploid Atlantic salmon were fed diets with a low (LP, total P: 7.1 g kg−1), medium (MP, total P: 9.4 g kg−1) or high (HP, total P: 16.3 g kg−1) phosphorous (P) level from first feeding (0.18 g) to transfer to sea water (~50 g, duration: 203 days) and subsequently fed a commercial diet in sea water for 426 days (~3 kg). This study examined the short- and long-term effects of dietary P on freshwater performance (mortality, growth), vertebral deformities (radiology), bone cell activity (ALP and TRACP enzyme activity in vertebrae and scales, and fgf23, bgp and igf-I relative gene expression in vertebrae), bone mineralization (ash content) and some parameters related to fish condition (heart and liver size). Irrespective of ploidy, at seawater transfer, fish fed the MP diet had significantly highest length and weight and those fed the LP diet significantly lowest length and weight, while those fed the HP diet had intermediate lengths and weights. Increased dietary phosphorus reduced deformities in both ploidies at seawater transfer; however, triploids fed the LP and MP diets had more deformities than diploids fed the respective diets, while there was no ploidy effect observed for fish fed the HP diet. The vertebral bone ash content at seawater transfer was significantly higher in diploids than in triploids when fed the MP diet only. Alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRACP) enzyme activities and relative gene expression of bone hormones involved in metabolism of plasma phosphate (fgf23) and bone growth (bgp) were not affected by ploidy at seawater transfer, but by dietary P level; LP increased ALP activity and reduced TRACP activity and fgf23 and bgp expression levels in vertebral bone. In scales, LP increased both ALP and TRACP activity. At the termination of the seawater period, the group-wise pattern in occurrence of vertebral deformities was the same as at seawater transfer. The present results on mortality, growth, bone mineralization and development of skeletal deformities all demonstrate that triploids have a higher P requirement than diploids in fresh water. This study shows that an optimalization of P nutrition for triploid Atlantic salmon can improve health and welfare and reduce down-grading of triploid salmon.
... Previous recommendations in relation to egg quality (Taylor et al., 2011), incubation temperature (Fraser et al., 2013(Fraser et al., , 2014 and dietary phosphorus (P) supply (Fjelldal et al., 2016) towards optimizing triploid survival, growth and development, were followed in the present study. The here observed growth pattern, with lower triploid weight prior to first feeding (34 dph) and during the fry interval (34 dph-109 dph) but reaching comparable weight at the parr stage (162 dph), concurs with previous studies comparing diploid and triploid salmon in freshwater under optimal growing conditions and reared separately (Amoroso et al., 2016;Carter et al., 1994;Cotter et al., 2002;McGeachy et al., 1995;O'Flynn et al., 1997;Taylor et al., 2011Taylor et al., , 2013. Although triploids are generally smaller during the larval stage up to several weeks or months after first feeding, they eventually catch up with diploids once feeding is established and even reach superior growth that is carried over through smolting. ...
... Triploid fry (109 dph) showed lower HSI, suggesting either less metabolically active liver or delayed somatic development, which might have contributed to the lower triploid weight observed prior to first feeding and during the fry interval (34 dph-109 dph). This result is consistent with observations by Cotter et al. (2002), who reported lower visceral weight in freshwater triploid salmon of similar size, though this difference was not statistically confirmed. Differences in whole fish and visceral weight following first feeding can be attributed to the higher incidence of non-feeders in the triploid group (Carter et al., 1994;Cotter et al., 2002) and to differences in fish distribution in the water column and tank, and consequent access to feed (McGeachy et al., 1995). ...
... This result is consistent with observations by Cotter et al. (2002), who reported lower visceral weight in freshwater triploid salmon of similar size, though this difference was not statistically confirmed. Differences in whole fish and visceral weight following first feeding can be attributed to the higher incidence of non-feeders in the triploid group (Carter et al., 1994;Cotter et al., 2002) and to differences in fish distribution in the water column and tank, and consequent access to feed (McGeachy et al., 1995). In the present study, it was observed that triploids were approximately one week slower than diploids to disperse though the water column and access the surface for first feeding, showing a tendency to feed off the bottom of the crate with frequent rejection of feed pellets (Amoroso et al., 2016). ...
Article
There is currently renewed interest in farming triploid Atlantic salmon. Improving farming requires identifying triploid specific phenotypic and physiological traits that are uniquely derived from ploidy per se and developed under optimal growing conditions. This study investigated firstly, the impact of ploidy on growth performance and whole body composition of Atlantic salmon at different early freshwater stages [34dph (days post-hatching) alevin, 109dph fry, and 162dph parr] and secondly, whether phenotypic differences at these stages were reflected in protein samples collected from whole fish, white muscle or liver tissue. Female diploid and triploid Atlantic salmon (n=3) were first fed at 35dph and then maintained by feeding to satiation on commercial feeds. Triploids were significantly lower in weight at the late alevin and fry stages but matched diploid weight at the parr stage. The whole-body lipid content was significantly higher for triploids at the parr stage, while the whole-body lipid class profile was broadly similar and was largely not affected by ploidy. Comparative label-free shotgun proteomic analysis did not detect significant alterations in protein expression between diploids and triploids at any growth stage. The present results indicate that ploidy under optimal growing conditions and during early freshwater stages only result in small phenotypic differences in weight and whole body lipid content that were not reflected at the proteome level. These findings suggest that optimal husbandry conditions for freshwater Atlantic salmon are similar between ploidies, at least for all-female populations.
... Sterility protects somatic growth, survival, and flesh quality from the negative effects of sexual maturation (Benfey, 1999;Johnson, Dickhoff, & Utter, 1986;Sheehan et al., 1999;Thorgaard, 1983). In the long run, the genetic and ecological impact of interactions between wild and cultured fishes is strongly minimized by an artificial induction of triploidy (Cotter et al., 2002). ...
... The study was conducted at a commercial freshwater rainbow trout farm in Bafra Derbent Dam (Kuzey Su Ürünleri Inc., in Bafra-Samsun/Turkey) and where the experimental fish were also obtained. Since the allocation of cages was limited, only all-female diploids (AFD) and all-female triploids (AFT) were used, as previously reported by Galbreath, St Jean, Anderson, and Thorgaard (1994); Ojolick, Cusack, Benfey, and Kerr (1995);and Cotter et al. (2002), and reared in six rectangle net cages (5 × 5 × 5 m; 1 cm mesh size). ...
... Earlier studies showed similar survival rates between diploid and triploid juvenile rainbow trout reared under optimal rearing conditions (Chevassus, Guyomard, Chourrout, & Quillet, 1983;Quillet, Chevassus, Blanc, Krieg, & Chourrout, 1988). However under nonoptimal conditions (high water temperature, low oxygen, etc.), survival rate of triploid fish is less than diploids (Bonnet et al., 1999;Cotter et al., 2002;Galbreath et al., 1994;Johnson et al., 1986 (1995) reported that mortality rates of triploid and diploid rainbow trout were 68% and 39%, respectively, when the water temperature exceed 21°C. Myers and Hershberger (1991) reported that the mortality of triploid rainbow trout was more than those of diploids, when the water temperature rises above 18.4°C. ...
Article
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This study compares the performance (in terms of survival and growth), biochemical and fatty acid compositions among all female diploid (AFD) and triploid (AFT) rainbow trout (Oncorhynchus mykiss). AFD and AFT fish with mean initial weights of 1,040.1 ± 1.3 and 1,039.7 ± 1.6 g, respectively, were reared and fed from March to August with a commercially extruded trout feed in a commercial freshwater fishfarm located in the Black Sea region (Samsun, Turkey). Survival was reduced throughout the experimental period in the AFT group with increasing water temperatures. At the end of the experiment, survival rates were 98.57 ± 1.43% and 82.38 ± 7.39% for the AFD and AFT groups, respectively. The AFD group showed significantly better growth performances in terms of weight gain, feed conversion rate (FCR), relative growth rate (RGR) and specific growth rate (SGR) than the AFT group (p < .05). Significantly less protein and greater fat content were also observed in the AFT group (p < .05). There was no significant difference between groups for fatty acid composition in meat, except for stearic acid (SA, C18:0) and docosahexaenoic acid (DHA, 22:6 n-3). While the greatest SA concentration was in the AFT group, the greatest DHA concentration was observed in the AFD group (p < .05). The results indicate that female triploid rainbow trout are more susceptible to suboptimal environmental conditions (especially to higher water temperatures) than female diploids. Although poor triploid performance was observed in this study, relative productivity might be enhanced by rearing triploids in optimal environmental conditions.
... In our study, mortality during embryonic and larval stages (from fertilization to hatching, up to first feeding) was higher in triploid Atlantic salmon compared to diploids and similar during early rearing in accordance with several studies ( Sutterlin et al. 1987;Mcgeachy, Benfey & Friars 1995;O'Flynn et al. 1997;Benfey 2001). Others studies found no differences between ploidies ( Leclercq et al. 2011;Taylor et al. 2011Taylor et al. , 2013) or higher mortality in triploids during both phases ( Galbreath et al. 1994;Cotter et al. 2002;Fraser et al. 2014a). Mortality in both ploidies occurred in the period from fertilization to first feeding and in the following phases it was generally low and decreasing over time in accordance with that reported by most of the cited studies. ...
... Mortality in both ploidies occurred in the period from fertilization to first feeding and in the following phases it was generally low and decreasing over time in accordance with that reported by most of the cited studies. During the second experiment, it was higher in triploids than diploids at both temperatures, in accordance with mortality in the same stage of development reported by Cotter et al. (2002). ...
... Nevertheless, both ploidies had the same growth rate. Triploids generally have lower weight compared to diploids during the larval stage up to several weeks or months after first feeding when triploids are usually of equal size ( Carter et al. 1994;Galbreath et al. 1994;Mcgeachy et al. 1995;O'Flynn et al. 1997;Cotter et al. 2002;Oppedal, Taranger & Hansen 2003;Taylor et al. 2011). A possible explanation for triploids being smaller than diploids after first feeding may lie in differences in distribution in the water column and tank and consequent access to feed ( Jungalwalla 1991;Mcgeachy et al. 1995) or differences in food consumption compared to diploids ( Carter et al. 1994). ...
Article
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Triploid Atlantic salmon tend to develop a higher prevalence of skeletal anomalies. This tendency may be exacerbated by an inadequate rearing temperature. Early juvenile all-female diploid and triploid Atlantic salmon were screened for skeletal anomalies in consecutive experiments to include two size ranges: the first tested the effect of ploidy (0.2-8 g) and the second the effect of ploidy, temperature (14 °C and 18 °C) and their interaction (8-60 g). The first experiment showed that ploidy had no effect on skeletal anomaly prevalence. A high prevalence of opercular shortening was observed (average prevalence in both ploidies 85.8%) and short lower jaws were common (highest prevalence observed 11.3%). In the second experiment, ploidy, but not temperature, affected the prevalence of short lower jaw (diploids > triploids) and lower jaw deformity (triploids > diploids, highest prevalence observed 11.1% triploids and 2.7% diploids) with a trend indicating a possible developmental link between the two jaw anomalies in triploids. A radiological assessment (n = 240 individuals) showed that at both temperatures triploids had a significantly (P < 0.05) lower number of vertebrae and higher prevalence of deformed individuals. These findings (second experiment) suggest ploidy was more influential than temperature in this study.
... After 14 months of rearing under aquaculture conditions, the weight of the triploid rainbow trout examined in this study significantly exceeded the weight of the diploids. Although some other studies on triploid salmonid species show similar trends (O'Flynn et al. 1997;Oppedal et al. 2003), there are reports showing no significant differences between the weight of juvenile triploid and diploid fish (Cotter et al. 2002;Aussanasuwannakul et al. 2011). On the other hand, during the early development stages, triploids tend to have a lower body weight compared to diploids, a trend that persists until the maturation stage (Solar et al. 1984;Chourrout et al. 1986;Withler et al. 1995;Chiasson et al. 2009). ...
... 1.8%) was observed in the brown trout Salmo trutta m. fario (Preston et al. 2013). In the Atlantic salmon, deformity rates ranged from 2 to 48.9% in triploids and from 0.66 to 24.4% in their diploid counterparts (O'Flynn et al. 1997;Sadler et al. 2001;Cotter et al. 2002;Fjelldal & Hansen 2010: Leclercq et al. 2011Fraser et al. 2013;Taylor et al. 2014). Studies on triploidization of the Atlantic cod showed that 72% of triploids and 42% of their diploid siblings had body abnormalities (Opstad et al., 2013). ...
... Deformities in the thoracic region led to the observation of fish with humpback, while deformities in the caudal area resulted in the phenotype with a shortened tail (Fig. 2D). Similar deformities were previously described in the triploid rainbow trout (Weber et al. 2014) and in the triploid Atlantic salmon (Cotter et al. 2002;Fjelldal & Hansen 2010). The presence of body deformities in aquaculture species is one of the most important problems in fish farming. ...
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Due to the cytogenetic incompatibility, triploid fish are usually infertile and are not affected by a decline in growth, survival and meat quality, which accompanies the process of sexual maturation in diploid specimens. Thus, artificial triploidization has been proposed for fish production in the case of species with early sexual maturation, such as rainbow trout. However, the use of this technique is limited by increased ratios of skeletal deformities observed in triploid specimens. The main objective of this research was to compare the proportion and variety of body abnormalities in diploid and triploid 14-month-old rainbow trout from commercial stocks, using external body shape examination, radiography and whole-mount skeletal staining. Individuals with externally observed body deformities (scoliosis, humpback, shortened tail and jaw deformities) accounted for 0.45% of the diploid stock and 3.83% of the triploid stock. X-rays and whole-mount skeletal staining of deformed individuals showed spine deformities, including compressions and fusions of vertebrae. Abnormalities observed in diploid and triploid rainbow trout examined during this study were non-lethal, however, they may negatively affect the condition of fish. Fish with skeletal deformities are not aesthetically pleasing, thus an increased ratio of such deformations in fish produced for commercial purposes may result in real economic losses.
... On the down size, experiments on the commercial culture of triploid Atlantic salmon were abandoned in the Fundy region of Canada when the triploids proved highly susceptible to the infectious salmon anaemia virus. A study by Cotter et al. (2002) showed more promising results than previous studies, with the performance of triploid salmon considered commercially acceptable in the freshwater phase. In the sea cages, however, the yield of triploids was less than that of diploids, largely as a consequence of the higher mortality sustained by triploids during atypically severe conditions associated with an infestation with a protozoan gill parasite Amoeba spp. ...
... The incidence of deformities was generally low. A higher proportion of the diploids had hump-back deformities, whereas a higher proportion of the triploids had severe eye cataracts (Cotter et al. 2002). In ranching experiments, the return to the coast and to freshwater was lower for triploid than for diploid salmon (Cotter et al. 2000, Wilkins et al. 2001. ...
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Since the mid-1960s, Atlantic salmon Salmo salar farming has grown into a large industry within and beyond the native range of the species. Norway, Chile, Scotland and Canada are the largest producers (46, 31, 10 and 7% of total production in 2005). A number of environmental concerns have arisen from the phenomenal growth of the industry. This report from the Technical Working Group on Escapes of the Salmon Aquaculture Dialogue aims at examining and evaluating i) the incidence and impacts of escaped farmed salmon in nature, and ii) the technologies and efforts to prevent escapes and to reduce their impacts upon wild salmon and the environment. This document: • reviews the status of current research and our understanding of the issues, • identifies significant conclusions/issues resolved by past research, and • documents specific knowledge gaps and research needs. Detailed information on salmon production, reported escapes from fish farms and monitoring of escaped farmed salmon in nature is given for each of the salmon producing countries. Escapes from fish farms occur from marine net pens in all salmon producing countries, as both repeated “trickle” losses of relatively small numbers of fish, and through large-scale episodic events. Numbers of farmed salmon escaping to the wild are large relative to the abundance of their wild conspecifics. Nearly all salmon producing countries have established routines for reporting at least large-scale escapes from sea cage sites, but the magnitude of unreported escapes is unknown. Information on low-level leakage and escapes from freshwater hatcheries remains uniformly poor. Negative effects by escaped farmed salmon on wild Atlantic salmon populations have been scientifically documented. Negative effects include both ecological interactions and genetic impacts of inter-breeding. A large number of studies point to negative effects, and outcomes for wild populations are either mostly negative and at best neutral. It has been shown that inter-breeding of farm with wild salmon can result in reduced lifetime success, lowered individual fitness, and decreases in production over at least two generations. Nearly one third of the total world production of Atlantic salmon is in regions where the species is exotic. There is evidence of successful spawning of Atlantic salmon in three streams in British Columbia, Canada, but whether escaped Atlantic salmon have established breeding populations along the North American West Coast still remains uncertain. Spawning of escaped farmed Atlantic salmon has not been documented in Chile or Tasmania. The Atlantic salmon is a poor colonizer outside its native range. The probability that escaped Atlantic salmon will establish populations where the species is exotic seems low, but the possibility cannot be ruled out. It is difficult to predict if or how Atlantic salmon will adapt to the regions where they are exotic, partly because research to study potential impacts in many of these regions is limited. The most important management issue at present is the need to reduce the numbers of escaped farmed salmon in nature. Among technologies and efforts to reduce impacts of escapes, sterilisation and farm exclusion zones look to be among the most promising, although significant research to fine-tune and study the effects of these approaches is needed. Given the compelling evidence pointing towards a high risk of negative impacts by escaped farmed salmon on wild salmon populations (or on native fish/other organisms in the case of escapes as alien species), and recognising the need to continually improve on our knowledge of the interactions between cultured and wild Atlantic salmon, the members of this working group would like to emphasise that the most pressing research priorities are linked to: 1) technologies and efforts for containment (escape prevention), and 2) approaches to reduce impacts of escapees.
... Lower jaw deformity (LJD) has been the most frequently reported skeletal abnormality in triploid Atlantic salmon (Sutterlin et al., 1987; Jungalwalla, 1991; McGeachy et al., 1995; Lijalad and Powell, 2009), although cataract, reduced gill surface area (GSA), gill filament deformity syndrome (GFD) and various other spinal deformities are also readily reported (Sadler et al., 2001; Oppedal et al., 2003). Furthermore, triploids have often showed greater variability both within and between families, and Contents lists available at ScienceDirect Aquaculture j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / a q u a -o n l i n e subsequently, numerous studies over the last decade have recommended the need to establish selection programs for successful triploid production (Bonnet et al., 1999; Friars et al., 2001; Cotter et al., 2002; Oppedal et al., 2003; Johnson et al., 2004). The ability to produce out-of-season smolts has been one of the greatest developments and assets to the salmon aquaculture industry. ...
... Consequently, in commercial production, photoperiod and thermal regimes can be manipulated so that fish smolt out-of-season and at ages of 1 year or less (Thrush et al., 1994; Duston and Saunders, 1995;). However, to date, studies in triploid Atlantic salmon have only focused on ambient (S1) smolt production (McGeachy et al., 1995; O'Flynn et al., 1997; Benfey, 2001; Friars et al., 2001; Cotter et al., 2002; Oppedal et al., 2003), and it has been proposed that incomplete smoltification may explain in part, poor seawater survival and performance in triploids (Boeuf et al., 1994; Galbreath and Thorgaard, 1995). Certainly it is well established that in normal diploid stocks high growth rates and sufficient energy stores allow individuals to achieve the size threshold necessary for smoltification (Solbakken et al., 1994; Skilbrei, 1988 Skilbrei, , 1991 Handeland and Stefansson, 2001; Berrill et al., 2006) and individuals that do not meet these thresholds fail to smolt. ...
Article
Production of sterile triploid Atlantic salmon (Salmo salar) would appear to be the best strategy to address the growing concerns on environmental impacts of escapees. However, the industry relies on a year round supply of smolts to ensure continual production and to date the production of out-of-season (S0+) triploid smolts has not been reported. The present study demonstrates that S0+ triploid smolts can be produced using an accelerated "square-wave" photoperiod (LL–LD 9.5:14.5–LL) under ambient water temperature. Such a regime advanced the timing of smoltification by 3 months (S0+) relative to their siblings under an ambient photoperiod (S1+) as observed through body silvering, fin darkening, decrease in condition and significantly increased gill Na + , K + -ATPase activity. Importantly, triploid S0+ fish smolted 4 weeks earlier than their diploid siblings. In S1+ populations, no difference in smolt time was observed although triploid fish also achieved a higher weight. Furthermore, deformity prevalence was very low during the fresh (≤ 5%) and seawater (≤ 2.5%) stages within both ploidies mainly represented by spinal deformity and operculum shortening. Family effects for growth and condition were clear, however, no significant family/ploidy interactions were observed although this was based on only two full-sib crosses. These results are promising but there is still a long way to go before triploid can become a commercial reality. Further studies are required to optimize and refine husbandry protocols, define breeding strategies especially regarding family selection and overall better understand triploid salmon physiology.
... Substantial research has been done on the production performance of triploids of various teleosts (Piferrer et al., 2009). However, in Atlantic salmon, for example, observations of lower survival and growth rates (Cotter et al., 2002 ), and a higher prevalence of skeletal deformities (Fjelldal and Hansen, 2010) have limited the use of triploid salmon in commercial faming. The aim of this experiment was therefore to investigate the effect of triploidization induced by hydrostatic pressure on the growth, survival and development of deformities from the egg stage to the juvenile stage in Contents lists available at SciVerse ScienceDirect Aquaculture j o u r n a l h o m e p a g e : w w w . ...
... Growth data comparing diploid and triploid fish show wide variations. McGeachy et al. (1995) and Friars et al. (2001) found that mixed-sex groups of triploid and diploid Atlantic salmon grew equally well in fresh water, while Cotter et al. (2002) found that diploids were significantly heavier about eight weeks after the commencement of start-feeding. Peruzzi et al. (2004) found slower growth in triploid than in diploid sea bass. ...
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This study investigated the performance of triploid Atlantic cod (Gadus morhua L.) produced in an intensive feeding system. Eggs pooled from three females fertilized with sperm from two males were either triploidized by hydrostatic pressure (58,600 kPa, 5 min, 6 °C) 30 min post-fertilization, or were maintained as untreated controls, and then reared under identical standard protocols until day 220 post-hatch. Mortality and growth were monitored from start-feeding while vertebral deformities were assessed by radiology on day 220 post-hatch.The triploid cod had lower survival than the diploid group from start-feeding and during early on-growing. On day 53, there was a significantly higher number of deformed fish among the triploid than the diploid cod. There was also a significantly higher prevalence of fish with one or more deformed vertebrae and prevalence of lordosis in triploids than diploids. The triploid group weighed significantly more than the diploid group before onset of feeding. The results of this study, which is the first that deals with skeletal deformities in triploid farmed Atlantic cod, are in line with previous findings that triploid teleosts are more prone to develop bone deformities. However, the mechanisms underlying this phenomenon are, still unknown.
... In this context, there is increasing interest in the use of triploid salmon in aquaculture, as triploid fish, with three sets of chromosomes (3N), are functionally sterile (reviewed by Benfey, 1999Benfey, , 2015Maxime, 2008;Pifferer et al., 2009). However, the aquaculture industry has been reluctant to adopt the use of triploid Atlantic salmon as reports suggest they are inferior to diploid fish due to poorer growth, higher mortalities (Carter et al., 1994;Cotter et al., 2002;Friars et al., 2001;Johnstone et al., 1991;Galbreath et al., 1994;Jungalwalla et al., 1991;O'Flynn et al., 1997;Taylor et al., 2013), and the increased prevalence of skeletal deformities (Fjelldal and Hansen, 2010) and ocular cataracts (Wall and Richards, 1992). Recent research has shown that lowering water temperature during egg incubation, and increasing dietary phosphorus and histidine can reduce the occurrence of skeletal deformities Fraser et al., 2015a) and ocular cataracts (Taylor et al., 2015) in triploid Atlantic salmon. ...
... Reports on reduced growth performance in triploid Atlantic salmon are mostly related to the seawater phase (Friars et al., 2001;Cotter et al., 2002;Taylor et al., 2013). The majority of the Norwegian Atlantic salmon aquaculture grow-out takes place in floating net pens in seawater, where the fish are exposed to large seasonal variation in water temperature (from 2 to 19 °C; Oppedal et al., 2011). ...
Article
The use of sterile triploids in Atlantic salmon aquaculture would mitigate the environmental risks associated with introgressive hybridization between escaped farmed and wild Atlantic salmon. However, production of farmed triploid salmon is limited due to reports of poorer growth and higher mortality when compared to diploids, in particular under sub-optimal environmental conditions. To address these concerns, we monitored triploid and diploid Atlantic salmon post-smolts at temperatures between 3 and 18 °C and 100% oxygen saturation (O2 sat), and additional periods of 60% O2 sat (hypoxia) at 6 or 18 °C, respectively. Feed intake and oxygen consumption rate were monitored throughout the experimental period. Muscle and blood samples were collected at 100 and 60% O2 sat at 6 and 18 °C for analysis of white muscle energy phosphates (creatine phosphate, adenosine triphosphate) and carbohydrate fuels (glucose, glycogen) as well as blood clinical chemistry (whole blood: hematocrit; plasma: Na⁺, K⁺, Cl⁻, glucose, lactate, pH, triacylglycerol). Mortality was similar between ploidies, but higher in triploids compared to diploids during reduced O2 sat at 18 °C. Compared to diploids, triploids had higher feed intake (% biomass) at ≤ 9 °C, but lower feed intake at ≥ 15 °C. Feed intake peaked at 12 and 15 °C for triploids and diploids, respectively. Triploids progressively reduced feed intake with increasing temperature after peak feeding, indicating reduced scope for specific dynamic action with increasing water temperature. During hypoxia, triploids had lower feed intake than diploids at 6 and 18 °C. The difference in feed intake was not associated with any ploidy effect on body weight gain or feed conversion ratio, but triploids had greater body length growth compared to diploids. At ≥ 15 °C triploids consumed less oxygen than diploids. In the white musculature, the only observed difference between ploidies was a lower level of glycogen in triploids compared to diploids at 18 °C and 100% O2 sat. In the blood plasma, the concentration of ions was lower and glucose level higher in triploids compared to diploids at 18 °C and 60% O2 sat. The results of this study indicate that triploid Atlantic salmon post-smolts can substitute diploids, but are less tolerant to high seawater temperature and low O2 sat. For sea-cage farming of triploid salmon post-smolts, this would favour production areas with maximum temperatures of 15 °C and sufficient oxygen.
... Variation in performance between different genetic stocks of salmon should be expected (O'Flynn et al., 1999;Wolters et al., 2009;Wolters, 2010); therefore, quantifying the range of this variation would be helpful for land-based farmers selecting egg suppliers for their facility. Additionally, performance between commercially available all-female diploids and triploids would be expected to differ from established diploid mixed-sex Atlantic salmon stocks (Cotter et al., 2002;Taylor et al., 2013). ...
... In the final, concurrent diploid and triploid all-female production cycle, diploid all-female fish (B2) began to outperform triploid allfemale counterparts (B3) after similar growth to 2.5 kg. Cotter et al. (2002) observed similar growth between triploid and diploid all-female salmon in freshwater stages; however, diploid growth began to outperform triploids in saltwater at approximately 2.5 kg. This was attributed to the anabolic effects brought on by the onset of maturation in diploid fish. ...
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Interest in land-based farms using recirculating aquaculture systems (RAS) for market-size Atlantic salmon (Salmo salar) continues to grow, and several commercial facilities are already rearing fish. Performance data for commercially available mixed-sex, all-female, and triploid all-female Atlantic salmon reared to market-size in freshwater land-based facilities, however, are limited, particularly for European strain fish. Accordingly, eight groups of European-sourced Atlantic salmon (five groups of diploid mixed-sex, two groups of diploid all-female, and one group of triploid all-female fish) were reared from eyed egg to market-size in a semi-commercial scale land-based aquaculture systems over five separate production cycles to quantify performance metrics. Fish reached market-size (4−5 kg) in 24.7–26.3 months post-hatch. Fish were reared at a mean water temperature of 12.3–13.7 °C from first feeding to a mean size of 466–1265 g, then 13.3–15.1 °C during growout. On average, all-female groups grew faster than mixed-sex groups; however, environmental conditions and performance of individual cohorts varied. In a comingled production cycle, diploid all-female salmon grew faster than triploid counterparts. Early maturation rates ranged from 0 % to 67 %, with a mean maturation rate of 34 % for diploid mixed-sex fish and 67 % and 13 % for two diploid all-female groups, respectively. Triploid all-female Atlantic salmon did not mature. This research confirms biological and technological feasibility of growing Atlantic salmon to market-size in land-based systems but controlling early maturation of diploid salmon remained a challenge under the conditions utilized in these trials. This research provides important data inputs to optimize operational and financial projections for existing and potential land-based Atlantic salmon farms.
... After the initial mortality associated with the handling and shock treatments in the triploidisation protocols, the difference in survival between triploids and diploids are less pronounced. In Atlantic salmon, freshwater mortality is reported to be higher in triploids in both experimental and commercial studies (McGeachy et al., 1995;O'Flynn et al., 1998;Benfey, 2001;Cotter et al., 2002). However, mortality rates are often within commercially acceptable levels, with the highest mortality during embryonic and larval development prior to first-feeding (Johnson et al., 2004). ...
... In one of the few studies to show enhanced growth of triploid salmon under commercial conditions it was evident that there were significant family/year class differences observed between ploidies advocating the need for selection to obtain the best performers (O'Flynn et al., 1997). Numerous studies now recommend the need for selection programs for successful triploid production in salmonids, particularly since triploids often show greater variability in performance both within and between families (Bonnet et al., 1999;Friars et al., 2001;Cotter et al., 2002;Oppedal et al., 2003). Significantly enhanced growth of triploid Atlantic salmon under continuous light (LL) relative to diploids has been observed (Oppedal et al., 2003), suggesting that some environmental conditions are particularly beneficial for triploids, and that poorer growth reported in some triploid stocks may be due to unfavourable husbandry regimes. ...
... However, triploidy in farm Atlantic salmon has been resisted because the process can render stocks increasingly susceptible to cataracts and vertebral malformations (Piferrer et al. 2009;Taylor et al. 2013). Some studies have reported increased mortalities of triploid fish in freshwater or at sea (Galbreath and Thorgaard 1995;McGeachy et al. 1995;Cotter et al. 2002), and there are conflicting results that find reduced, equal or enhanced growth of triploids under aquaculture (e.g. Leclercq et al. 2011;Oppedal et al. 2003;Galbreath and Thorgaard 1995;Withler et al., 1995). ...
Article
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Adaptations at the gamete level (a) evolve quickly, (b) appear sensitive to inbreeding and outbreeding and (c) have important influences on potential to reproduce. We apply this understanding to problems posed by escaped farm salmon and measure their potential to reproduce in the wild. Farm Atlantic salmon (Salmo salar) are a threat to biodiversity, because they escape in large numbers and can introgress, dilute or disrupt locally adapted wild gene pools. Experiments at the whole fish level have found farm reproductive potential to be significant, but inferior compared to wild adults, especially for males. Here, we assess reproductive performance at the gamete level through detailed in vitro comparisons of the form, function, fertility, compatibility and competitiveness of farm versus wild Atlantic salmon sperm and eggs, in conditions mimicking the natural gametic microenvironment, using fish raised under similar environmental conditions. Despite selective domestication and reduced genetic diversity, we find functional equivalence in all farm fish gamete traits compared with their wild ancestral strain. Our results identify a clear threat of farm salmon reproduction with wild fish and therefore encourage further consideration of using triploid farm strains with optimized traits for aquaculture and fish welfare, as triploid fish remain reproductively sterile following escape.
... Triploid salmonid survival is often reported to be reduced under communal ploidy rearing (Bonnet et al., 1999;Galbreath and Thorgaard, 1995;Galbreath et al., 1994;Johnson et al., 1986;O'Flynn et al., 1997;Ojolick et al., 1995;Quillet and Gaigon, 1990;Withler et al., 1995), while others report no difference (McGeachy et al., 1995;O'Flynn et al., 1997), particularly when ploidy are grown separately Leclercq et al., 2011;Oppedal et al., 2003;Taylor et al., 2011Taylor et al., , 2012. Similarly, conflicting data regarding triploid salmonid growth relative to diploids also exists where reduced (Galbreath et al., 1994;Withler et al., 1995) or comparable growth (McGeachy et al., 1995;Withler et al., 1998) has been reported under communal rearing, while lower (Benfey, 2001;Friars et al., 2001), equal (Cotter et al., 2002) or greater growth in both fresh (Galbreath et al., 1994;Taylor et al., 2012Taylor et al., , 2013 and salt water (Leclercq et al., 2011;Oppedal et al., 2003) has been reported when grown in isolation. ...
... Aquaculture studies support our finding that feeding and diet preferences of diploid and triploid trout are similar (Boulanger 1991;O'Keefe and Benfey 1999). However, in other species others have found evidence of lower performance of triploid versus diploid fish (rainbow trout, Simon et al. 1993;Atlantic salmon, Carter et al. 1994;Cotter et al. 2002) that could have resulted from some undocumented or unknown aspect of feeding ecology. ...
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Despite numerous negative impacts, nonnative trout are still being stocked to provide economically and socially valuable sport fisheries in western mountain lakes. We evaluated relative performance and potential differences in feeding strategy and competitive ability of triploid versus diploid brook trout Salvelinus fontinalis in alpine lakes, as well as behavioral and performance differences of diploid and triploid brook trout in two controlled experimental settings: behavioral experiments in the laboratory and performance evaluations in ponds. Across lakes, catch per unit effort (CPUE) and relative weight (Wr) were not significantly different between ploidy levels. Mean sizes were also similar between ploidy levels except in two of the larger lakes where diploids attained slightly larger sizes (approximately 20 mm longer). We observed no significant differences between diploids and triploids in diet, diet preference, or trophic structure. Similarly, growth and condition did not differ between ploidy levels in smaller-scale pond experiments, and aggressive behavior did not differ between ploidy levels (fed or unfed fish trials) in the laboratory. Independent of ploidy level, the relative performance of brook trout varied widely among lakes, a pattern that appeared to be a function of lake size or a factor that covaries with lake size such as temperature regime or carrying capacity. In summary, we observed no significant differences in the relative performance of brook trout from either ploidy level across a number of indices, systems, and environmental conditions, nor any indication that one group is more aggressive or a superior competitor than the other. Collectively, these results suggest that triploid brook trout will offer a more risk-averse and promising management opportunity when they are stocked to these lakes and elsewhere to simultaneously meet the needs for the sport fishery and conservation objectives.Received February 6, 2012; accepted August 27, 2012
... The induction of the triploid condition in fish has usually been reported to be accompanied by modification in physiology that may reduce the resistance to acute stress (Ojolick et al., 1995a;Cotter et al., 2002). This lower resistance can influence the productive performances of triploids during artificial rearing usually characterized by crowding and/or occasional reduction in oxygen concentration. ...
Article
Haematological features were compared between diploid and triploid specimens of the ray-finned fish Umbrina cirrosa. No significant differences between diploids and triploids were reported in haematocrit and total haemoglobin concentration, but erythrocytes and thrombocytes were significantly greater in size in triploids. Glycaemia was significantly lower in diploids, whereas triploid erythrocytes were more resistant to osmotic stress. In triploids, a greater fraction of leukocytes was positive for alkaline phosphatase activity, when stimulated with Bacillus clausii spores, otherwise no significant increase of oxygen consumption was observed in triploid leukocytes after stimulation, based on assays for superoxide anions. Triploids were characterized by a lower concentration of circulating blood cells with a lower surface/volume ratio when compared with diploids. These features may lead to a general disadvantage of triploids in withstanding stress conditions: a situation that needs to be taken into account in aquaculture practice.
... production and what was reported at slaughter), both pointing toward higher mortality in triploids. Most of the triploid monthly mortality seems to be correlated with delousing treatments, possibly indicating a lower resistance to handling and severe stressors, a theory suggested in other studies (Benfey 1999;Cotter et al. 2002). On farm A, the combination of lice infestation, delousing treatments, and PD and CMS outbreaks were assumed responsible for high mortality in both groups. ...
Article
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Avoiding genetic interactions between wild and farmed Atlantic salmon is regarded as one of the major requirements for a sustainable salmon aquaculture industry. For this reason, farming functional sterile triploids has been suggested as a possible solution. However, knowledge about how triploids cope under commercial conditions is lacking. In the present study, we compared the performance of diploid and triploid Atlantic salmon among four Norwegian aquaculture companies. Diploid and triploid groups of the same genetic line were farmed in western, mid, and northern Norway under commercial conditions from seawater transfer until slaughter.Overall, triploid salmon exhibited reduced survival, higher incidence of emaciated fish, and scored, on average, a lower quality rating during primary processing. The results highlight the need for further research on how to improve the welfare and performance of triploid salmon in commercial aquaculture operations.
... temperatures. Several other studies have shown that triploids have growth rates similar (Cotter et al., 2002;Fraser et al., 2013;Galbreath and Thorgaard, 1995) or higher than diploid siblings in seawater (Leclercq et al., 2011;O'Flynn et al., 1997;Oppedal et al., 2003). Several new studies also show that triploid salmon generally grow faster than diploids in freshwater under moderate temperatures (e.g. ...
Article
Sterilization by triploid induction prevents interbreeding between escaped farmed salmon and wild stocks, but reduced performance of triploids at high seawater temperatures has been reported. As high temperature may be followed by limited oxygen (O2) supply in net cages, this study compared the effect of reducing O2 from 100% to 70% of air saturation (termed hypoxia) on parameters of production performance (feed intake, growth, feed conversion ratio, mortality), and physiological status (plasma K+, Cl−, Na+, osmolality, glucose, creatinine (Cr), bilirubin, triacylglycerol (TAG) and alkaline phosphatase (ALP) concentrations) in triploid versus diploid Atlantic salmon kept at high seawater temperature (19 °C). Two triplicate groups of diploid and two triplicate groups of triploid Atlantic salmon post-smolts were acclimated to 10 °C and 100% O2 before experiment start up. During the experiment, temperature was maintained at 10 °C for 10 days, increased to 19 °C over 9 days and kept stable at 19 °C until the experiment ended (day 51). From day 22 to 51, the O2 level was reduced from 100% O2 to 70% O2 in one diploid and one triploid group. The abbreviated group names are 2N100, 2N70, 3N100 and 3N70. Triploidy led to reductions of feed intake and growth, and this effect was amplified by reducing O2 from 100% to 70% O2. Analyses from blood samples drawn on day 51 show that plasma levels of Cl−, TAG, ALP and bilirubin were lowered in triploids in general, and that plasma Cr levels trebled and plasma K+ levels dropped in triploids subjected to 70% O2 for 29 days. Mortality was also significantly higher in the 3N70 group. According to these effects, the following order of production performance is suggested at high seawater temperature (best to worst): 2N100 > 2N70 ≥ 3N100 > 3N70. An interesting difference in the behavior between diploid and triploid fish was observed during the experiment: triploids generally moved against the tank water current, ram ventilating, as opposed to diploids, which displayed normal gill ventilation and were in part moving along with the current. The inability of triploid Atlantic salmon to withstand high temperature in combination with moderate hypoxia could set limitations to the geographical distribution of triploid salmon farming.
... In general, there is a higher incidence of deformities of triploid fish in comparison to their diploid counterparts. For example, triploid Atlantic salmon (Salmo salar L.) exhibit a higher rate of lower jaw and gill filament deformities (Sadler et al., 2001) and eye cataracts (Cotter et al., 2002) than diploid salmon. However, triploidy was artificially induced in each of these studies and harsh gamete manipulations may have been the root cause of the physical abnormalities rather than the triploid state itself (Piferrer et al., 2009). ...
... In the current study, the analysis of the association between the age and weight of the tambaqui showed that fish subjected to the T42/4°C triploidy induction presented better growth performance than the diploid controls. Similarly, Cotter et al. (2002) claimed that triploid Atlantic salmon (Salmo salar) presented better growth performance than diploid fish at the age of 8 weeks after starting feeding. This growth is due to factors such as the higher capability of muscular differentiation of the induced triploid individuals in comparison with their diploid homologues (Peng et al. 2016). ...
Article
This study assessed the effectiveness of double thermal shock to induce triploidy in tambaqui (Colossoma macropomum) and compared the fertilization, survival, and growth performance of diploid and triploid fish. Freshly fertilized eggs were subjected to heat shock (40 or 42°C) for 2 min and, after that, a cold shock (4°C) for 25 min. Eggs that were not exposed to the heat/cold shock were used as control. Ploidy was assessed by flow cytometry. Larvae (21 days after hatching) treated with thermal shocks displayed reduced fertilization and survival rates. The larvae in the 40/4°C and 42/4°C groups displayed higher growth than the control group. The juveniles (135 days after hatching) in the 42/4°C group showed higher growth than the other groups. The 42/4°C shock induced triploidy in 17.5% of nuclei. The double thermal shock 42/4°C did not induce a high rate of triploidization in tambaqui but produced fish with better growth performance.
... The induction of sterility using triploidization to date is the only non-GMO, commercially and publically acceptable means of achieving sterility in fish and shellfish (Piferrer et al. 2009), and is a wellestablished method in several commercially important farmed species. However, triploid Atlantic salmon have been reported in many studies to show lower survival and growth performance (Galbreath et al. 1994;Galbreath & Thorgaard 1995;McGeachy et al. 1995;Withler et al. 1995;O'Flynn et al. 1997;Cotter et al. 2002;Shrimpton et al. 2007), although more recent studies have shown comparable or improved growth and survival (Oppedal et al. 2003;Burke et al. 2010;Taylor et al. 2011Taylor et al. , 2012. This may be a reflection of the improved husbandry and increased knowledge of culture requirements of current stocks. ...
Article
The study investigated cataract preventive effects of dietary histidine (His) supplementation in triploid Atlantic salmon during seawater grow-out. Groups of individually PIT tagged diploid (2N) and triploid (3N) postsmolts were fed one of two supplemented dietary histidine levels; low (L, 12.6 g kg−1 diet) or high (H, 17.4 g kg−1 diet) from March to September following their first sea winter. Low severity cataracts were detected in both ploidy prior to supplemented His diet application. Thereafter, 3N-L showed progression of cataract development in the second spring-summer period, while development was inhibited in 3N-H. Severity of cataract showed a strong family effect. A positive correlation between initial triploid seawater growth (weight and TGC) under increasing water temperature and cataract severity was identified as a major risk factor. The relationship was reversed at harvest, where triploids were on average 7.5% smaller than their diploid siblings. Lens N-acetyl-histidine content reflected dietary His inclusion level and cataract severity, although no significant differences in lens His content were evident between ploidy or dietary groups. Results indicate that triploid Atlantic salmon appear to have a higher dietary histidine requirement than diploids and that preventative measures can be taken to mitigate further cataract development.
... Triploid salmon show inconsistent farm performance compared to diploids in seawater with reports of equal (O'Flynn et al., 1997;Smedley et al., 2016), better (O'Flynn et al., 1997;Oppedal et al., 2003) or poorer growth (Cotter et al., 2002;Taylor et al., 2013;Fraser et al., 2013). Indeed, a recent industrial project in Norway that utilised data from commercial trials in Northern Norway concluded triploid salmon should not be used as autumn (i.e. ...
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The use of reproductively sterile triploid salmonids would enhance the environmental sustainability of the aquaculture industry by preventing genetic exchange between escapees and wild conspecifics. To this end, we assessed smoltification and early seawater performance (241 days) following a yearling production cycle (i.e. spring smolts) in diploid and triploid female Atlantic salmon (Salmo salar) × male brown trout (Salmo trutta) hybrids compared to purebred diploid and triploid salmon. During freshwater rearing (n = 180/group), hybrids demonstrated a degree of bimodality in body size, significantly (p < 0.05) more so in diploid than triploid hybrids (11 and 37% in the lower mode, respectively) that was not seen in purebred salmon of either ploidy. This resulted in diploid hybrids being 66% smaller on average at sea transfer, whereas no hybridisation effect was seen in triploids, and both triploid groups were significantly heavier (16–43%) than diploid salmon. Irrespective of ploidy, lower mode hybrids grew poorly and showed low survival in seawater, suggesting they had failed to undergo smoltification. However, the upper mode diploid hybrids showed a similar Na⁺/K⁺-ATPase (NKA) enzyme activity surge during the spring as in diploid and triploid salmon, despite a higher ratio of the freshwater to seawater mRNA abundance of the NKA subunits (nkaα1a and nkaα1b) and a reduced plasma cortisol surge. At the end of the experimental period, both hybrids weighed significantly less than their salmon counterparts although the hybrid effect was again greater in diploids (71% smaller) than triploids (6% smaller). In addition, both triploid groups were on average significantly heavier (15–22%) than diploid salmon. As such, both triploid Atlantic salmon and triploid hybrids can show enhanced growth performance from juveniles up to post-smolts compared to diploid salmon in an aquaculture setting.
... Pilot-scale evaluation of triploid Atlantic salmon for aquaculture began around the same time in France (Quillet & Gaignon 1990), Atlantic Canada (Friars & Benfey 1991;Sutterlin & Collier 1991;McGeachy et al. 1995;O'Flynn et al. 1997;Benfey 2001;Friars et al. 2001;Pepper et al. 2004), Scotland (Johnstone et al. 1991;Johnstone 1993;McCarthy et al. 1996), Tasmania (Jungalwalla 1991) and the west-coast USA (Galbreath et al. 1994;Galbreath & Thorgaard 1995). Similar precommercial trials later were undertaken in Ireland (Cotter et al. 2002) and Norway (Oppedal et al. 2003). Results from these trials were mixed and are difficult to compare due to differences in strains of fish, husbandry methods and environmental conditions, as well as limitations in experimental design. ...
Article
Atlantic salmon (Salmo salar) dominates aquaculture production in its native North Atlantic range, raising concerns about the impacts of escaped farmed fish on wild populations. While physical confinement and operational management practices have improved steadily with the development of this industry, some escapes are inevitable. In the absence of effective measures for the rapid recapture of escaped fish, the only practical method currently available to minimize their impacts on wild populations is to ensure that they are female triploids and therefore reproductively sterile. The technology for producing all-female triploid populations of Atlantic salmon is simple and easily applied on a commercial scale, and routinely results in populations that are entirely female and >98% triploid. Aside from sterility, there are no population-wide phenotypic effects of triploidy, although triploids do tend to perform less well than diploids with respect to commercial culture characteristics and are also less likely than escaped diploids to outcompete or displace native salmon. Some uncertainties exist with respect to their disease resistance and their potential to become reservoirs for the spread of pathogens to wild populations. If the spawning potential of escaped farmed Atlantic salmon is deemed to pose an unacceptable risk to native populations, then all-female triploid populations could be used as an alternative to reduce risk. Research should continue to focus on improving triploid performance through breeding programmes and optimization of husbandry conditions (including nutrition, environmental conditions and fish health), with the goal of making triploids an attractive option for fish farmers.
... Similarly, based on body weight, we previously found triploids to have relatively larger livers than diploids (Fraser et al., 2014a;Fjelldal et al., 2016), whereas others have found no ploidy effect (this study, Tibbetts et al., 2013;Bowden et al., 2018;Taylor et al., 2019) or smaller relative sizes in triploids (Nuez-Ortín et al., 2017). For visceral mass, our lower relative size in triploids fits with the result of Taylor et al. (2019), whereas Cotter et al. (2002) only reported a strong trend for the same effect. Relative heart and liver size are known to be plastic in salmon and influenced by environmental factors (Gamperl and Farrell, 2004;Døskeland et al., 2016). ...
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Sterile triploid Atlantic salmon (Salmo salar) show inconsistent seawater grow-out, but the reason why remains unclear. The purpose of this study was to determine the salinity optima of triploid post-smolts. Diploids and triploids were assessed for smoltification status during an underyearling smolt regime before being transferred to one of four different salinities, 0, 11, 23 and 35 ppt at 12 °C and under 24 h continuous light for 83 days. During this period, fish growth, plasma biochemistry, and production traits (vertebral deformities, ocular cataracts, sexual maturation) were monitored. Molecular biomarkers in the gill (nkaα1a, nkaα1b, nkcc1a) suggested triploids reached peak smolt earlier than diploids and began the desmoltification process before the start of the salinity treatments, however this was not reflected in gill Na⁺/K⁺-ATPase enzyme activity. At the initiation of the salinity treatments triploids were significantly larger than diploids (mean weight g ± SE: 71 ± 0.7 and 87.2 ± 0.8 for diploids and triploids, respectively) and there was a ploidy effect on post-smolt growth, with body weight showing a clearer positive trend with salinity in diploids (0 < 11 = 23 = 35 ppt) than in triploids (0 < 11 < 35 = 23 ppt) (final mean weight g ± SE: 255.2 ± 7.4, 303.9 ± 9, 313.9 ± 9 and 342.4 ± 12 for diploids and 322.9 ± 9.7, 361.7 ± 10.7, 425.9 ± 12.1, 415.2 ± 12.2 for triploids at 0, 11, 23, and 35 ppt, respectively). Plasma Na⁺ and Cl⁻ increased, but plasma pH decreased, with increasing salinity in both ploidy. However, ploidy only had transient effects on plasma biochemistry depending on the salinity treatment. There was no ploidy effect on vertebral deformities (21% of both ploidy had one or more deformed vertebra). In contrast, triploids had a significantly higher prevalence of ocular cataracts (84 vs 98% in diploids and triploids, respectively) with a higher mean cataract score (mean ± SE: 1.93 ± 0.1 and 2.78 ± 0.1 for diploids and triploids, respectively), but a significantly lower prevalence of pubertal male post-smolts (15 vs 2% in diploids and triploids, respectively). Salinity treatment had no effect on vertebral deformities, cataracts, or post-smolt sexual maturation. In summary, there was a ploidy mismatch for smoltification biomarkers in the gill and salinity had a strong effect on post-smolt growth, but the effects were ploidy dependent.
... By and large, it has been believed that triploid fish populations have higher and quicker growth rates compared to their diploid counterparts; nonetheless, current studies have yielded conflicting results, at least with regard to salmonids. Most information has been collected from Atlantic salmon studies reporting either higher (Friars et al. 2001;Oppedal et al. 2003) or lower (Cotter et al. 2002) growth performance. The higher amount of DNA present in triploid cells entails a nucleus size increase resulting in a total cell size increment, thus allowing for the maintenance of the nucleus-cytoplasmic ratio (reviewed in Benfey 2001). ...
Article
The induction of triploidization in fish is a very common practice in aquaculture. Although triploidization has been applied successfully in many salmonid species, little is known about the epigenetic mechanisms implicated in the maintenance of the normal functions of the new polyploid genome. By means of methylation-sensitive amplified polymorphism (MSAP) techniques, genome-wide methylation changes associated with triploidization were assessed in DNA samples obtained from diploid and triploid siblings of brown trout (Salmo trutta). Simple comparative body measurements showed that the triploid trout used in the study were statistically bigger, however, not heavier than their diploid counterparts. The statistical analysis of the MSAP data showed no significant differences between diploid and triploid brown trout in respect to brain, gill, heart, liver, kidney or muscle samples. Nonetheless, local analysis pointed to the possibility of differences in connection with concrete loci. This is the first study that has investigated DNA methylation alterations associated with triploidization in brown trout. Our results set the basis for new studies to be undertaken and provide a new approach concerning triploidization effects of the salmonid genome while also contributing to the better understanding of the genome-wide methylation processes. © 2015 Stichting International Foundation for Animal Genetics.
... By contrast TG/DIP fish showed enhanced growth rates compared to their NTG counterparts, which is in agreement with previous results reported by Tibbetts et al. (2013). Conventional triploid salmonids demonstrate inconsistent growth performance showing inferior (Carter et al., 1994;O'Flynn et al., 1997), equal (Cotter et al., 2002;McGeachy et al., 1995;Taylor et al., 2011) or superior (Burke et al., 2010;Fjelldal and Hansen, 2010;Galbreath et al., 1994;Galbreath and Thirgaard, 1995;Jungalwalla, 1991;Taylor et al., 2011Taylor et al., , 2012 growth rates than their NTG/DIP siblings in freshwater culture. The discrepancy in these results is most likely related to large variations in strain, growth phase, diet formulation, methodology and environmental conditions of different studies. ...
Article
This study assessed the capacity of non-transgenic (NTG) and growth-hormone transgenic (TG; gene construct EO-1α) Atlantic salmon (Salmo salar L.), comprised of conventional diploid (DIP) and reproductively-sterile triploid (TRIP) fish, to utilize a diet containing relatively high amounts of plant protein (PP) concomitant with lower levels of fish meal (FM) protein. Triplicate groups of full-sibling NTG/DIP, NTG/TRIP, TG/DIP and TG/TRIP salmon (initial weight, 27–35 g) were held in freshwater and fed two experimental diets until they exceeded 400% growth. Two isonitrogenous (50% crude protein), isolipidic (21% lipid) and isoenergetic (22 MJ/kg gross energy) experimental diets were tested. The control diet (FM) contained 64 and 36%, while PP diet contained 32 and 68% of total dietary protein from FM and PP, respectively. TG and NTG fish achieved the target (> 150 g) weight in 89 and 206 days, respectively. TG fish exhibited significantly higher specific growth rates (SGR) (2.48 vs 0.7%/day) and thermal growth coefficient (TGC) (3.04 vs 0.79) than NTG, regardless of ploidy or diet. TG/TRIP fish had significantly lower growth rates than DIP due to lower feed intake, while no ploidy effect was observed within the NTG group. Feed conversion ratio (FCR) was significantly better in TG/DIP and TG/TRIP fish having achieved the same target weight with 20–25% less feed due to improved protein utilization and retention efficiency compared to NTG fish. NTG fish had higher digestibility of protein (93% vs 89%), lipid (95% vs 94%) and energy (89% vs 85%) relative to their TG siblings, and was similar between DIP and TRIP fish. Nutrients' digestibility was significantly lower in TG fish fed PP diet than those fed FM diet, regardless of ploidy. At the end of the study, TG fish had significantly lower whole-body protein (56% vs 59%) and higher lipid (36% vs 34%) and energy (2746 vs 2694 kJ/100 g) content than NTG fish. However, as a result of the rapid growth rate and efficient feed utilization, nutrient gain and retention efficiencies were significantly higher in TG than NTG fish. DIP and TRIP TG Atlantic salmon have the ability to maintain accelerated growth even when fed a high PP diet (68% of dietary protein), which may have important benefits for the production of growth hormone transgenic Atlantic salmon.
... A recent study by Atkins and Benfey (2008) showed triploid salmonids to have a lower thermal optimum than diploids, and the superior growth of triploids in the current study may reflect the relatively low water temperature at the time of experimentation (9-11°C). The consistently lower CF of triploids was expected; this is well documented for Atlantic salmon throughout the life cycle Quillet and Gaignon, 1990;Galbreath and Thorgaard, 1995;O'Flynn et al., 1997;Friars et al., 2001;Cotter et al., 2002;Oppedal et al., 2003), although some studies have shown equivalent CFs for diploid and triploid Atlantic salmon at the end of the freshwater stage and as smolts (Boeuf et al., 1994;Galbreath and Thorgaard, 1995). ...
Article
Although triploidy induction is a reliable method for producing sterile fish for aquaculture and fisheries management, little is known about how triploidy influences nutrition and bioenergetics of fish. The aim of this study was to determine whether triploidy affects nutrient uptake and body composition in fish, using juvenile Atlantic salmon (Salmo salar) as the test species and varying the levels of dietary phosphorus. Triplicate groups of sibling triploids and diploids (45 g initial weight) were fed isocaloric diets with 0.76, 0.99 and 1.39% total phosphorus in a 12-week growth trial, followed by a feed digestibility trial with diets having 0.67, 0.93 and 1.15% total phosphorus. Triploids had a higher growth rate and lower condition factor than diploids during the growth trial, with no difference in feed conversion ratio. Whole-body lipid and energy levels, as well as nitrogen and energy efficiency ratios, were higher in the triploids, but ash and moisture levels were lower. Triploids initially had lower plasma phosphorus levels than diploids, but on the final sampling day there was no difference between ploidies in levels of plasma phosphorus, bone ash and phosphorus within the bone ash. Apparent digestibility coefficients for phosphorus, ash and dry matter were not significantly different between triploids and diploids. The observed effects of triploidy on growth and body composition therefore cannot be attributed to phosphorus utilization and metabolism.
... The induction of atriploid condition in fish has usually been reported to be accompanied by modification in physiology that may reduce the resistance to acute stress (Ojolick et al., 1995a;Cotter et al., 2002;Ballarin et al., 2004). This lower resistance can influence the productivity of triploids during artificial rearing, which is characterized by crowding and/or occasional reductions in oxygen concentration. ...
Article
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Haematological features pertaining to aerobic capability were compared between diploid and triploid specimens of the Far Eastern catfish, Silurus asotus. No significant differences between diploids and triploids were found for the haematocrit value, total haemoglobin, and mean corpuscular haemoglobin concentration, while the mean corpuscular volume, mean corpuscular haemoglobin, and plasma glucose concentration were significantly higher in triploids than in diploids, and the number of red blood cells was significantly lower in triploids than in diploids. The oxygen consumption rate did not differ significantly between diploid and triploid fish (P > 0.05). Nevertheless, the respiratory frequency was higher in triploids than in diploids (P< 0.05). Triploids were characterized by a lower concentration of circulating blood cells, and aquaculture practice should consider the need for a lower surface to volume ratio.
... Neither all-female culture nor triploidy are extensively practiced in Atlantic salmon aquaculture. Comparisons between diploids and triploids, even in all-female production, have shown inconsistent results among studies in terms of growth, survival, and rates of deformity (McGeachy et al. 1996 ;Friars et al. 2001 ;Sadler et al. 2001 ;Cotter et al. 2002 ;Oppedal et al. 2003 ;Taylor et al. 2011 ;Sacobie et al. 2012 ). ...
Article
The Food and Agriculture Organization of the United Nations (FAO) estimates that in 2012 aquaculture production of fish will meet or exceed that of the capture fisheries for the first time. Thus, we have just turned the corner from a predominantly hunting gathering approach to meeting our nutritional needs from fish, to a farming approach. In 2012, 327 finfish species and five hybrids were covered by FAO aquaculture statistics, although farming of carps, tilapias, salmonids, and catfishes account for most of food-fish production from aquaculture. Although for most major species at least part of production is based on what might be considered domesticated animals, only limited production in most species is based on farming of improved lines of fish or is fully independent of wild seedstock. Consistent with the infancy of most aquaculture industries, much of the development and implementation of reproductive technologies over the past 100 years has been directed at completion of the life cycle in captivity in order to increase seed production and begin the process of domestication. The selection of species to farm and the emphasis of selective breeding must also take into account other ways to modify performance of an animal. Reproductive technologies have also been developed and implemented to affect many performance traits among fishes. Examples include technologies to control gender, alter time of sexual maturation, and induce sterilization. These technologies help take advantage of sexually dimorphic growth, overcome problems with growth performance and flesh quality associated with sexual maturation, and genetic containment. Reproductive technologies developed to advance aquaculture and how these technologies have been implemented to advance various sectors of the aquaculture industry are discussed. Finally, we will present some thoughts regarding future directions for reproductive technologies and their applications in finfish aquaculture.
... Similar to our results, several authors reported a negative effect of triploidy on the growth in salmonid species such as rainbow trout and brown trout (Bonnet et al. 1999), Atlantic salmon (Friars et al. 2001), coho salmon (Devlin et al. 2004), and Chinook salmon (Johnson et al. 2004;Shrimpton et al. 2007Shrimpton et al. , 2012. However, growth performances in triploids have not been significantly different compared to their diploid counterparts in other studies (Cotter et al. 2002;Withler et al. 1998). ...
Article
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Two-dimensional gel electrophoresis (2-DE), matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF/TOF) mass spectrometry, and database searching were used to analyze the effects of triploidization heat shock treatment on protein expression in rainbow trout eyed embryo and fry. After fertilization, the eggs were incubated at 10 °C for 10 min. Half of the eggs were then subjected to heat shock for 10 min submerged in a 28 °C water bath to induce triploidy. The remainder was incubated normally and used as diploid controls. Specimens of eyed embryos and fry were taken on 18 and 76 days post-fertilization, respectively. In the eyed embryo extracts, seven protein spots were significantly changed in abundance between the control and heat-shocked groups and one of these was decreased while the others were increased in the heat shock-treated group. Of the spots that were shown to change in abundance in the eyed embryos with heat shock treatment, two were identified as vitellogenin, while the others were creatine kinase and angiotensin I. In the 2-DE from the fry muscle extraction, 23 spots were significantly changed in abundance between the diploid and triploid groups. Nineteen of these showed a decreased abundance in diploids, while the remaining four spots had an increased abundance. Triploidization caused differential expression of muscle metabolic proteins including triosephosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, and beta-enolase. Myosin heavy chain as a structural protein was also found to change in abundance in triploids. The altered expression of both structural and metabolic proteins in triploids was consistent with their increased cell size and lower growth performance.
... In salmonids, triploidy has variable effects on growth compared to diploid conspecifics. Several studies limited to commercial strains have shown that triploids show reduced [36,37] or equal growth to diploids [14,38], however, studies have also shown that triploids can grow better than diploids [39,40], although this appears to be life-stage specific [6,41]. Environmental factors may also influence the performance of triploids, as it is often shown that they do not perform well in sub-optimal conditions [14]. ...
Article
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Background The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid performance often show contrasting results. Studies have identified dosage and dosage-compensation effects for gene expression between triploid and diploid salmonids, but no study has investigated how ploidy and parent-origin effects interact on a polygenic trait in divergent lines of Atlantic salmon (i.e. slow growing wild versus fast growing domesticated phenotype). This study utilised two experiments relating to the freshwater growth of diploid and triploid groups of pure wild (0% domesticated genome), pure domesticated (100% domesticated genome), and F1 reciprocal hybrid (33%, 50% or 66% domesticated genome) salmon where triploidy was either artificially induced (experiment 1) or naturally developed/spontaneous (experiment 2). Results In both experiments, reciprocal hybrid growth was influenced by the dosage effect of the second maternal chromosome, with growth increasing as ploidy level increased in individuals with a domesticated dam (from 50% to 66% domesticated genome), and the inverse in individuals with a wild dam (from 50% to 33% domesticated genome). Conclusions We demonstrate that the combined effect of ploidy and parent-origin on growth, a polygenic trait, is regulated in an additive pattern. Therefore, in order to maximise growth potential, the aquaculture industry should consider placing more emphasis on the breeding value of the dam than the sire when producing triploid families for commercial production. Electronic supplementary material The online version of this article (doi:10.1186/s12863-017-0502-x) contains supplementary material, which is available to authorized users.
... With regards to the gastrointestinal tract (GIT), morphological and functional differentiation occurs in the very early life stages and is influenced by environment and nutrition (53) . Overall, triploids had a lower survival rate during the stimulus and marine phases, which was consistent with previous studies (54)(55)(56) . Similarly, lower growth rates in triploid Atlantic salmon fry during the stimulus phase was also consistent with previous studies (57,58) . ...
Article
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The present study investigated nutritional programming in Atlantic salmon to improve utilisation of a vegetable-based diet. At first exogenous feeding, fry were fed either a marine-based diet (Diet M stimulus , 80% fishmeal (FM)/4% fish oil (FO)) or a vegetable-based diet (Diet V stimulus , 10% FM/0% FO) for 3 weeks. Subsequently, all fish were then fed under the same conditions with a commercial, marine-based, diet for 15 weeks and thereafter challenged with a second V diet (Diet V challenge , 10% FM/0% FO) for 6 weeks. Diploid and triploid siblings were run in parallel to examine ploidy effects. Growth performance, feed intake, nutrient utilisation and intestinal morphology were monitored. Fish initially given Diet V stimulus (V-fish) showed 24 % higher growth rate and 23 % better feed efficiency compared with M-fish when later challenged with Diet V challenge . There was no difference in feed intake between nutritional histories, but increased nutrient retentions highlighted the improved utilisation of a V diet in V-fish. There were generally few significant effects of nutritional history or ploidy on enteritis scores in the distal intestine after the challenge phase as only V-triploids showed a significant increase ( P <0·05) in total score. The data highlighted that the positive effects were most likely a result of nutritional programming and the ability to respond better when challenged later in life may be attributed to physiological and/or metabolic changes induced by the stimulus. This novel study showed the potential of nutritional programming to improve the use of plant raw material ingredients in feeds for Atlantic salmon.
... KEY WORDS: Ploidy · Sterile · Growth · Feed intake · Thermal optimum · Energy metabolism · Salmo salar OPEN PEN ACCESS CCESS first started in the 1970s, implementation has been slow. The main concerns have been lower growth rates (Jungalwalla 1991, Friars et al. 2001, Taylor et al. 2013, reduced stress tolerance and increased mortality, particularly under suboptimal environmental conditions, when compared to diploids (Ojolick et al. 1995, Cotter et al. 2002, Hyndman et al. 2003b, Hansen et al. 2015, Sambraus et al. 2017a. ...
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ABSTRACT: In salmon farming, the use of sterile triploids (3N) can mitigate the problem of escapees interbreeding with wild salmon. However, triploid salmon appear less tolerant to high water temperatures and low oxygen levels compared to diploids (2N). To investigate how the thermal performance and physiology of large (2.5 kg) triploid Atlantic salmon Salmo salar L. differs from those of diploids, both ploidies were subjected to water temperatures between 3 and 18°C. The fish were exposed to reduced oxygen saturations (O2 sat, 70%), termed hypoxia, at 6 and 18°C. Triploids fed more than diploids between 3 and 9°C and at similar levels at 12°C. At 15°C, the feed intake significantly dropped in both ploidies, although more in triploids. During hypoxia, feed intake was higher in triploids at 6°C and equal to diploids at 18°C. The overall feed conversion ratio was similar between ploidies. Muscle energy phosphates were generally lower in triploids than diploids, while muscle glucose, blood haemoglobin and haematocrit were lower in triploids than diploids at ≥12°C. Plasma lactate levels tended to be higher in triploids and increased with increasing temperature and at hypoxia in both ploidies. Plasma cortisol increased in both ploidies at high temperatures and was highest in triploids under hypoxic conditions at 18°C. Triploids had a higher cataract score at the start of the experiment and developed more cataracts throughout the experiment. The present findings show that large triploid Atlantic salmon perform better at colder water temperatures compared to diploids and differ in parts of their physiological expression at increasing and high temperature.
... Mortality rate in the current study from first-feeding to smolt did not differ statistically between ploidies or dietary P inclusion level in the diet, which is in accordance with most recent studies in triploids Taylor et al., 2012;Taylor et al., 2013) although some studies, including recent, have reported higher mortalities (O'Flynn et al., 1997;Cotter et al., 2002;Amoroso et al., 2016a). Such improvements in triploid survival in more recent studies may be attributed to a better understanding of factors affecting triploid performance including improved egg quality ) and a recommendation for lower egg incubation temperatures (Fraser et al., 2014c). ...
Article
In order to assess the effect of dietary phosphorus (P) in reducing vertebral malformations and improving freshwater (FW) performance in triploid Atlantic salmon (Salmo salar), both triploid and diploid Atlantic salmon were fed three different dietary P inclusion levels (low: 4.9, medium: 7.7, and high: 9.7 g available P kg⁻¹) from first feeding until smolt. Somatic and skeletal response was assessed at fry (~0.5 g), parr (~5 g) and smolt (~45 g) stages. Triploid parr initially grew faster on the high P diet, while groups fed low P resulted in a significantly higher weight at smolt. Image analysis of double stained Alcian blue and Alizarin red S fry revealed that low P fed triploid fish presented less well mineralised vertebrae, and significantly more malformed vertebrae in both parr and smolt stages following x-ray radiographic assessment. Triploid parr fed high and medium P had similar numbers of malformed vertebrae relative to their diploid counterparts but greater numbers than at smolt. Low P fed triploids had the highest prevalence of jaw and vertebral malformations as well as the highest number of deformed vertebrae in the central caudal vertebral region, which was more pronounced at parr than at smolt. Shorter vertebrae dorso-ventral lengths were observed throughout the spinal column (R1–R4) in parr fed low P and only in the caudal region (R3) at smolt. In parr, both ploidies showed reduced phosphate homeostasis protein fgf23 gene expression in vertebrae when fed low P diets, while triploids showed greater down-regulation of osteogenic factors (alp, opn and igf1r) between diets relative to diploids, suggesting possible greater active suppression of mineralisation and reduced osteogenic potential in triploids. No effects of diet or ploidy on gene expression were evident at smolt. Comparisons between development stages suggest early P supplementation in triploids is crucial for skeletal development. Ultimately, reducing vertebral deformities observed at smolt with higher P supplementation in triploids could contribute towards improving skeletal performance and welfare of the stocks in the marine phase.
... Due to these differences in gonadal development between males and females, male triploid fish were less heavy than triploid female counterparts. Production of all female triploid could be solution to this but so far, use of all female triploid did not provide greater growth performance compared to all female diploids (Cotter et al., 2002). ...
Article
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Early maturation has been one of the biological bottlenecks of commercializing Atlantic cod culture. To overcome the bottleneck, production of sterile fish through triploidy and other molecular techniques have been suggested and attempted. Although studies have been carried out on triploid performance of Atlantic cod, no studies have been conducted to see the performance of triploid fish at family level. We produced 29 triploid sibling families using standard hydrostatic pressure technique of newly fertilized eggs with parallel, untreated diploid families. Larvae were reared in separate tanks using standard rearing protocols until reaching 20 g and were PIT tagged. PIT tagged juveniles were transferred to sea cages in duplicate. At 34 months post-hatch, all the fish were sampled and body weight, liver weight and gonadal weight were recorded. Results showed that significant family differences exist between diploid and triploid families in gonadal development, especially for the females. Fish from triploid families had significantly smaller gonadosomatic index than fish from diploid families, but diploid families were heavier than the triploid families. Our result highlight the need for considering a parallel strategy for triploid family selection within the conventional diploid breeding program to exploit the existing variation in triploid performance.
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Aquaculture production continues to increase to satisfy global demand, and as such, issues relating to its environmental sustainability and the welfare of fish are becoming more prominent within society. Sterile triploid fish (possessing one additional chromosome set to the more natural diploid state) are in use in aquaculture and fisheries management to avoid the problems associated with unwanted early sexual maturation and genetic interactions between wild and cultured fish. Triploids are physiologically and behaviorally similar to diploids, although ploidy effects do exist. This review focuses on the welfare of triploid fish within aquaculture and fisheries management. The main conclusions are that triploids appear more susceptible to temperature stress, have a higher incidence of deformities, and are less aggressive than their diploid counterparts. However, considerable knowledge gaps exist in triploid physiology and performance; therefore, triploid requirements for water quality, nutritional requirements, stocking densities, and slaughter methods cannot be fully assessed. In addition, other than growth and survival, no information exists on the performance of triploids when released into natural environments, and this is of considerable concern, as triploids are commonly used in catch-and-release fisheries. These matters become more pressing with today's increased emphasis on animal welfare
Article
The use of triploid salmon for aquaculture is attractive as they do not mature sexually, limiting losses associated with poor flesh quality in mature fish and posing less genetic risk to wild stocks if they escape. Inconsistent survival and growth performance in triploid fish, however, has limited their implementation. In our study, ocean-type Chinook salmon (Oncorhynchus tshawytscha) were bred using replicated 3×3 factorial mating designs to create 18 families to test whether triploidization resulted in changes in growth and ionoregulation performance in freshwater and seawater. Eggs were pressure shocked after fertilization to create triploid offspring in a subset of each family. In spring, freshwater fish were sampled for size and gill Na+, K+-ATPase activity. Plasma chloride and cortisol were measured following a 24-h saltwater challenge. Growth performance was monitored for a further four months following transfer to sea water. We found significant effects of ploidy and sire (paternal effect) on smolt weight, as well as on gill Na+, K+-ATPase activity, although the latter did not correspond with performance in a 24-h saltwater challenge. Following four months of ocean growth, diploid animals were consistently larger, with greater circulating levels of insulin-like growth factor-1 than triploid sibs, although specific growth rates did not differ. Conversely, gill Na+, K+-ATPase activity at that time was significantly higher in triploid than diploid fish. When the phenotypic variance for the various traits was partitioned, triploids exhibited significantly greater additive genetic variance and maternal effects across all traits relative to diploid fish — indicating that gene dosage effects were primarily additive. The strong family effect indicates that genotype has a substantial role in determining the effects of ploidy manipulation on ionoregulatory and growth performance in Chinook salmon.
Article
The hatchery performance (growth, feed conversion, and survival) of rainbow trout Oncorhynchus mykiss was compared between diploid and triploid fish from three Utah strains: Fish Lake-DeSmet (FD), Sand Creek (SC), and Ten Sleep (TS). For FD, specific growth rates were slightly higher for triploids (2.79%/d) than for diploids (2.60%/d), but final mean weight at 108 d did not significantly differ. For SC and TS, there were no significant differences in final mean weight or specific growth rates after 138 or 122 d, respectively. Feed conversion ratios and fish mortality in the raceways did not differ significantly between diploids and triploids, except for SC for which mortality rates were slightly higher for triploids (4.0%) than diploids (2.1%). Possible differences in agonistic behavior between diploids and triploids were assessed by video observation of size-matched pairs (diploid-diploid, diploid-triploid, or triploid-triploid). There were no significant differences between diploid and triploid fish of any strain in the number of chases or counterattacks. To determine whether there were any differences in susceptibility to stocking and handling stressors, each strain was transported at high density for 4 h, then stocked into (1) tanks with ambient hatchery well water (control), (2) tanks with either high pH and high temperature (FD) or high temperature (TS and SC), or (3) the tail end of the raceway from which it came. There were no significant differences in mortality after 96 h between diploid and triploid fish for any of the three strains for any of the treatments. Poststocking survival of FD in a small, spring-fed lake was assessed by gill netting in the spring after fall stocking. No significant difference in overwinter survival was noted between diploid and triploid FD. Overall, the data indicate that triploid SC, FD, and TS rainbow trout perform equally well in the hatchery as diploid fish.
Chapter
Rainbow trout, a sport fish naturally grows well in cool and flowing water. However with decreasing water flows and pollution in many rivers due to climate change and variability, suitability of the natural habitat is threatened. Alternative production systems can be necessary to mitigate the negative impact. In this study we aimed to test the production potential of trout using cages in an inland dam. We selected fingerlings weighing 94 ± 5 g and compared production of trout in floating cages versus raceways with flowing water. Using non-parametric methods, we tested if there were differences in feed and growth patterns on fish in raceways and cages. Mann–Whitney U test showed that there was no significant difference (U = 40, p = 0.118) between feed intake for race ways and cages. Feed conversion ratio differently increased but did not differ among the two groups. Mann–Whitney U test showed that there was no significant difference (U = 87, p = 0.410) on overall fish mortality between raceway and cage groups. While care is needed on the initial handling of fingerlings and stocking to reduce mortalities, cages provide an alternative inexpensive method for growing trout in cool temperature environments.
Article
We characterized the physiological effects of exposure to pH9.5 on one domesticated and four wild strains of diploid and triploid juvenile rainbow trout (Oncorhynchus mykiss) over two consecutive years. In the first year, 35-70% of the individuals from the wild strains showed a loss of equilibrium (LOE) at 12h exposure to pH9.5, with all fish from wild strains experiencing a LOE by 48h. In contrast, <20% of the domesticated strain showed LOE over the 48h exposure to pH9.5. In our second experiment, similar strain effects were observed, but far fewer fish showed LOE (≤50% in all strains) over 72h at pH9.5. In both experiments, there was no effect of ploidy on time to LOE. In the fish that did not show LOE, high pH exposure resulted in significant increases in plasma, brain and muscle ammonia, with no effect of strain or ploidy on the extent of ammonia accumulation. Glutamine accumulated in the brain during high pH exposure, with a stoichiometric decrease in glutamate, but no differences were noted among strains or ploidies. Lactate also accumulated in the plasma to a similar extent in all trout strains and ploidies. Plasma chloride decreased at 24h exposure in all trout strains and ploidies, but recovered by 72h. No change was observed in plasma sodium. Overall, our data suggest that the domesticated strain of trout is more tolerant of pH9.5 than the wild strains, but these differences in tolerance cannot be explained by our sub-lethal assessment of ammonia balance or ion regulation. Copyright © 2014. Published by Elsevier Inc.
Chapter
Chromosome markers usually do not require as much development time as molecular markers, but they have the disadvantage of requiring living tissue. Once developed for a particular group, molecular methods are more efficient because multiple loci can be scored on a single gel. In addition, although DNA variation of some type is present in virtually every species, intraspecific chromosome variation may not be present. In fact it appears that marine fishes have much more stable karyotypes than freshwater fishes, so chromosome number variation is rare in them. Although chromosome number variation has been observed in shellfish, no intraspecific variation has been documented. Usually NOR staining will reveal intra-specific variation in almost any species, but it may not be stock-specific. Most species have a unique karyotype, so cytogenetic methods can be very valuable for analysis of hybrid zones between closely related species or subspecies. For fish species with intraspecific chromosome number variation, hatchery fish may have a different chromosome number than wild fish, so in that case it would be possible to estimate the percentage of hatchery vs. wild fish and identify any hybrids between the two using cytogenetic methods. Such variation is especially common in salmonid fishes, and often involves intraspecific translocation polymorphisms. In human genetics, molecular markers diagnostic for specific translocations involved in specific tumors and birth defects have been developed. These types of assays could make identification of chromosome variation more feasible for population studies in the future.
Article
Diploid (2N) and triploid (3N) sibling post-smolts were divided between six sea pens and fed: a standard commercial nutrient package diet (2 × 2N SP, 2 × 3N SP), or an iso-energetic nutrient boosted (higher dietary protein and phosphorous) package (2 × 3N BP) until market size. 3N groups initially grew significantly faster than 2N, and by harvest, 3N BP weighed significantly more (3210 ± 87 g) than 2N SP or 3N SP (3007 ± 64 g; 2965 ± 88 g), while there was no significant difference in weight between ploidy in SP diet. Higher visible vertebral (9.6 ± 0.4%) and jaw deformities (10.6 ± 1.2%) were observed in 3N compared to 2N (0.9 ± 0.1%; 1.3 ± 0.5%). However, x-ray radiography revealed that 3N BP and 2N SP had comparable levels of severely affected individuals at time of sea transfer, while 3N SP showed a 3 fold increase in the severity of malformed individuals. The tail region (R3) in 3N SP fish had both the lowest vertebral strength and stiffness and the highest number of deformed vertebrae. Fillet quality attributes were comparable between diet and ploidy. These findings show that triploid growth rate can be sustained until harvest throughout the seawater phase, and more importantly the progression of spinal deformity beyond that at sea transfer can be stabilised by increasing dietary P during the marine phase. Statement of relevance Tailored triploid specific aquafeeds must be formulated to support growth and prevent deformity in order to minimise welfare implications and allow exploitation of faster growth potential of triploid salmon within industry.
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The yellow catfish (Pelteobagrus fulvidraco) is a very important aquaculture species distributed in freshwater area of China. All-male yellow catfish is very popular in aquaculture because of their significant sex dimorphism phenomena. The males grow much faster than females in full-sibling family. However, the sex dimorphism mechanism is still unclear in yellow catfish. In order to better understand the genetic basis of yellow catfish sexual dimorphism, it is vital to map the sex-related traits and localize the candidate genes across yellow catfish whole genome. Here, we constructed a high-density linkage map of yellow catfish using genotyping-by-sequencing (GBS) strategy. A total of 5705 single-nucleotide polymorphism (SNP) markers were mapped to 26 different linkage groups (LGs) using 184 F1 offspring. The total genetic map length was 3071.59 cM, with an average interlocus distance of 0.54 cM. Eleven significant sex-related QTLs in yellow catfish were identified. Six sex-related genes were identified from the region of reference genome near these QTLs including amh, gnrhr, vasa, lnnr1, foxl2, and bmp15. The high-density genetic linkage map provides valuable resources for yellow catfish molecular assistant breeding and elucidating sex differentiation process. Moreover, the comparative genomic study was analyzed among yellow catfish, channel catfish, and zebrafish. It revealed highly conserved chromosomal distribution between yellow catfish and channel catfish.
Article
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In the present research we produced triploid, mitogynogenetic (doubled haploid; DH) and meiogynogenetic brook trout (Salvelinus fontinalis) to examine efficiency of these technologies and potential susceptibility of chromosome set manipulated individuals for the spinal disorders. Triploidy was induced by shocking (High Hydrostatic Pressure – HHP) of fertilized eggs 30 min. after insemination. In turn, gynogenetic development was induced by activation of eggs with UV-irradiated sperm. Activated eggs were then exposed to HHP shock applied 30 and 420 minutes after insemination to provide meiogynogenotes and gynogenetic DHs, respectively. When compared to non-manipulated diploids, the highest survival rates was observed among triploid brook trout while DHs showed the highest mortality. Malformation rates in the diploid larvae from the control groups did not exceed 7.0% while percentage of malformed triploid individuals equaled 19.1%. Drastically increased number of deformed larvae (> 30%) was observed in both, DH and meiogynogenetic individuals. Intensification of kyphosis and scoliosis was clearly demonstrated in the gynogenetic and triploid brook trout. Genetic factors such as increased number of sets of chromosomes in triploids and expression of lethal alleles in the gynogenetic fish plus side effects of HHP shock utilized for retention of the second polar body or inhibition of the first cell cleavage when induced triploid and gynogenetic development have been discussed to affect survival rates and prevalence for the skeletal deformities in the chromosome set manipulated brook trout.
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The aim of this study was to compare somatic growth and muscle fibre development in diploid and triploid siblings of Atlantic cod (Gadus morhua Linnaeus, 1758) during the larval stage. Newly hatched larvae were transferred into 200-L tanks, three tanks per ploidy group (70 larvae L−1, continuous light, gradually increasing seawater temperature 7–11°C and flow rates 50–117 L h−1). Larvae were fed rotifers from 2 to 22 days post hatch (dph), Artemia 19–31 dph and weaned onto a microparticulate diet from 26 dph until the end of the experiment. Measurements of growth (dry weight, standard length) and muscle cellullarity were taken at intervals between 1 and 44 dph. Ploidy groups showed a similar performance throughout the trial, although a marked stagnation in growth was observed for triploids during the weaning from Artemia onto dry feed. Overall, diploid and triploid cod larvae showed a similar development in muscle fibre growth pattern during the experimental period. For both groups, the total number of fast muscle fibres showed a 10-fold increase (from 384 to 3462), whereas the diameter of fast fibre increased from 8.9 to 13.3 μm (mean number from all treatments). Thus, a temporary but significant effect of triploidy on fast muscle fibre growth pattern was observed in 19 dph larvae in terms of fibre size and number, with triploids showing larger mean fast fibre diameter (11.62 ± 0.63 vs. 10.05 ± 0.34) and a lower number of fibres with a diameter <5 μm than their diploid siblings. Thus, this was found to be related to larvae size and to the differences in total fast fibre cross sectional areas rather than to ploidy status. Overall, our results suggest possible deficiencies in nutrients’ digestion and absorption of triploid cod larvae particularly during the transitional period from live food to inert diets.
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Induced triploidy is widely accepted as the most effective method for producing sterile fish for aquaculture and fisheries management. Artificially produced triploids generally differ from conspecific diploids in three fundamental ways: they are more heterozygous, they have larger but fewer cells in most tissues and organs, and their gonadal development is disrupted to some extent. Despite these basic biological differences, triploids are similar in most respects to diploids when examined at the whole animal level. The only clear differences relate to the effects of impaired gametogenesis on the reproductive physiology and behavior of triploids, especially in females. Other apparent differences include reduced aggressiveness, occasional specific morphological abnormalities, and inferior performance when reared under suboptimal conditions. The causes of these latter two problems are poorly understood but must be addressed if triploids are to be used more extensively.
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This paper addresses the genetic consequences of aquaculture on natural fish populations. The study is motivated by rapidly increasing numbers of intentionally and accidentally released fish and is based on empirical observations reported in the literature. A wide variety of outcomes, ranging from no detectable effect to complete introgression or displacement, has been observed following releases of cultured fish into natural settings. Where genetic effects on performance traits have been documented, they always appear to be negative in comparison with the unaffected native populations. These findings are consistent with theoretical considerations of the implications of elevated levels of gene flow between cultured and locally adapted natural populations; they raise concerns over the genetic future of many natural populations in the light of increasing numbers of released fish. Strategies for the genetic protection of native populations from the effects of aquaculture are outlined including more secure containment, the use of sterilized fish, and modifying the points of rearing and release. We recommend strong restrictions on gene flow from cultured to wild populations and effective monitoring of such gene flow.
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In this study, groups of diploid (control) and triploid brook trout were subjected to a 5 min acute handling/confinement stress. Blood samples were collected from equal numbers of diploid and triploid fish at regular predetermined intervals, beginning prior to confinement and continuing for up to 3h after confinement. These blood samples were used for the measurement of hematocrit and plasma cortisol and glucose concentrations. The effects of cohort sampling and the diel cycle on these variables were also analysed. Except for minor differences, both groups responded similarly to the acute stress, with short-term elevations in plasma cortisol and hematocrit levels, and a more sustained increase in plasma glucose levels. No significant differences were found between diploid and triploid fish in their reactions to cohort sampling. However, the act of removing an individual from a tank caused significant changes in plasma cortisol levels in cohorts remaining in that tank (p < 0.001). Significant diel effects were observed for both ploidy groups in plasma cortisol (p < 0.05) but not in plasma glucose or hematocrit.
Article
Heat shocks of 5 min at 32°C or hydrostatic pressure shocks of 3 or 6 min at 7.0 × 104 kPa (10 150 p.s.i.), when completed within 20 min of fertilization at 10°C, were found to induce 100% triploidy with 70–90% survival (relative to controls) in landlocked Atlantic salmon (Salmo salar L.). The identical heat shock yielded substantially lower numbers of triploids when applied 25 to 45 min after fertilization. Pressure shocks of longer duration (9 to 15 min at 7.0 × 104 kPa) or higher magnitude (6 min at 7.9 × 104 to 10.5 × 104 kPa) resulted in 100% mortality prior to hatching. Possible applications of these techniques to salmonid aquaculture are discussed.
Article
Variation in weight, growth, survival, and smolting was examined for nine fullsib families of diploid and triploid coho salmon (Oncorhynchus kisutch) from the Quinsam River B.C. Diploids survived substantially better than triploids from fertilization to hatching (94% vs. 43%), from hatching to ponding (96% vs. 76%), during freshwater rearing (92% vs. 75%), and during marine rearing (81% vs. 60%). About 77% of the diploids marked with coded wire (CW) tags smelted, whereas only 63% of the corresponding triploids smoked. About 71% of the diploids marked with passive integrated transponder (PIT) as well as CW tags smolted, whereas only 39% of the triploids carrying both types of tags smolted. Diploids were 65% heavier than the triploids at smolting, and 70% heavier after two summers of marine rearing. Marine growth of diploids was significantly faster than that of the triploids during the spring and summer of the year of maturity. The biomass of the diploid cohort was over three times greater than that of the triploid cohort at the termination of the experiment. Ploidy by family interactions for the characters examined were greatest during freshwater and early marine rearing. Although poor triploid performance was observed in this experiment, relative productivity may be enhanced by rearing triploids in isolation from diploids, or by a judicious choice of the triploid strain.
Article
Steroid hormone levels and patterns of growth have been examined between December and April in captive, marked Atlantic salmon destined to mature some months later (November). Changes in maiden fish of both sexes becoming mature after 1 year (grilse) or 2 years of sea-life have been described. Two groups of grilse were distinguished on the basis of their appearance in late June and their steroid hormone profiles and growth in spring. Serum 11-oxotestosterone levels were raised in the preceding December in that group of male grilse which could be identified as such by their appearance in late June. Levels peaked in February and early March. Maturing male grilse which could be identified only later in the summer did not show these changes. Maturing female grilse showed no changes in serum 17β-oestradiol over the sampling period irrespective of whether or not they could be identified as maturers in June. Body weights in male and female fish which could be identified as maturers in June were indistinguishable from each other over the sampling period but, after late March, were significantly greater than those in the other maturers and the fish which remained immature. Lengths differed similarly but only at a later date. However, analysis of specific growth rates suggests that the differences in both body weight and length began to be established in the period between February and March. Final maturity rate as grilse in the monitored group of fish greatly exceeded that in the parent group from which they had been derived. In males becoming mature after 2 years in the sea 11-oxotestosterone was raised throughout the sampling period, reaching peak values in January. In maturing females of the same age 17β-oestradiol levels were elevated throughout the sampling period and peaked in February.
Article
The impact of escaped farmed salmon on wild populations may have potentially negative genetic and ecological effects. There is widespread evidence that farmed salmon interact with wild salmon. The use of sterile fish in culture has been proposed as a means of eliminating genetic interaction and minimising the ecological effect of farmed salmon. In this study, the migration behaviour of groups of triploid salmon were investigated through the controlled release of microtagged triploid and diploid stocks on the western coast of Ireland. Mixed-sex and all-female stocks of ranched grilse origin were triploidised using hydrostatic pressure. Smolts were ranched from the hatchery of origin and two groups of post-smolts were released from cages in a marine site. The return of adult salmon from these experimental release groups to coastal and freshwater capture sites was monitored as part of the Irish national coded wire tag recovery programme. The return of triploid salmon from each of the release groups, both to the coast and to fresh water, was significantly reduced compared to diploid salmon. The highest percentage return to fresh water (2.25%) was in the ranched mixed-sex diploid group. In contrast, no salmon from the cage release groups returned to the hatchery location on the Burrishoole river system and recoveries in other freshwater systems were low (
Article
The use of sterile, triploid salmon for aquaculture would be an effective method of preventing genetic interactions between cultured and wild salmon. The studies presented in this paper compare the performance of six year classes of triploid and diploid salmon in freshwater and seawater stages of commercial production. Freshwater growth was comparable between triploids and diploids. Freshwater survival was also similar between triploids and diploids except that survival was lower in the triploids for the developmental interval between fertilization and first feeding. In sea water, triploids performed better than diploids in terms of growth. However, survival was lower in triploids and they showed a higher incidence of jaw deformities. In summary, the overall yields of triploids was lower than diploids under culture conditions.
Chapter
This note summarizes a review by Hindar et al. (1991) outlining the genetic consequences of aquaculture on natural fish populations. Publication of the full paper (Hindar et al., 1991) has preceded that of the present volume; this note is included to permitt a more complete presentation of the papers read at the Loen symposium on interactions between cultured and wild Atlantic salmon (Salmo salar).
Article
Confinement of juvenile Atlantic salmon Salmo salar from four different populations (all–female diploids, all–female triploids, mixed sex diploids and mixed sex triploids) either before (FW parr) or after (SW smolts) transfer to sea elevated plasma cortisol and plasma lactate from control levels irrespective of ploidy status. Both before and after confinement, plasma cortisol levels in SW smolts (6–174 ng ml–1) were higher than those in FW parr (4–58 ng ml–1), which possibly reflected the physiological challenge of acclimation to SW. Mixed sex populations of SW smolts had higher cortisol levels than all–female populations. The duration of confinement (1, 3 or 6 h) affected the magnitude of the plasma cortisol and lactate responses in SW smolts. Plasma cortisol levels in diploid and triploid SW smolts subjected to 2 h of confinement decreased to pre–stress levels within 6 h post–confinement. Plasma lactate levels were not significantly different from pre–stress levels 48 h after confinement. As no difference exists in primary and secondary stress responses of Atlantic salmon of differing ploidy status, it is unlikely that differences in mortality rates between diploid and triploid populations under commercial conditions can be attributed to differences in their physiological responses to periods of stress lasting up to 6 h.
Article
The salmonid aquaculture industry has recently been investigating the benefits and drawbacks of sterile triploids. Although studies have shown that triploids should not be restricted by their altered haematology under optimal conditions, little is known about their performance in sub-optimal environments. This study focused on the performance (in terms of growth and survival) of female triploid rainbow trout (Oncorhynchus mykiss) in comparison to female diploids at chronic high temperature. Triploid and diploid rainbow trout were reared in fibreglass tanks at 21 ± 1 °C for 23 days. At these chronic high temperatures, triploids had a significantly (P < 0.001) higher mortality rate in comparisons to diploids: 68.5% of the triploids (n = 175) died within 3 weeks at 21 ° C, while only 39% of the diploids (n = 167) died in this time period. Diploids had larger fork lengths (by 4.8%), body weights (by 23.9%) and condition factors (by 10.3%) than the triploids by the end of the experiment (P < 0.05 in all cases). The cause of fish mortality in this experiment was likely to be multifaceted, and influenced, and/or directly caused, by the stress of the experimental protocol. However, it is evident from these results that triploid rainbow trout did not survive or grow as well as diploids in chronic high water temperature conditions.
Article
The use of ploidy manipulation to produce sterile salmon has been investigated since the mid-1970s. Today, the techniques for producing triploids are well documented. In this study pressure shock techniques were employed to produce triploid Atlantic salmon on a commercial scale, and performance differences between triploids and diploids were assessed. A new 2.51 pressure vessel was designed and used to produce approximately 36 000 triploid salmon during the 1992 spawning season. This vessel was highly successful in inducing triploidy, as determined by flow cytometry. Performance was based on survival and growth, which were monitored from the egg stage until the time of smolting. There were no significant differences in cumulative survival throughout the experiment. During April, May and June of 1993, triploids were significantly smaller than their diploid counterparts (P < 0.05). However, from July 1993 until February 1994 there were no differences in size. In February 1994 the smolting rate was determined by classifying those fish greater than 13 cm as smolt. The success rates were 86% and 88% for triploids and diploids, respectively.
Article
Triploid rainbow trout were produced by heat shock treatment of eggs soon after fertilization with either normal sperm or sperm from masculinised females. The proportion of triploid fry, as judged from red blood cell nuclear volume, varied between 75% and 100% in three experiments using different batches of eggs from an autumn-spawning strain of trout while a single batch of eggs from a winter-spawning strain yielded 50% triploids.A microscopic examination of the gonads was made on 5-month-old fish weighing between 1 and 3 g. In female controls the ovaries were packed with oocytes while those from female triploids, although showing the typical lamellar structure of an ovary, contained no oocytes, thus indicating that female triploids are sterile. The testes from triploid males appeared to be developing normally.The use of masculinized females combined with heat shock treatment of eggs to produce triploids, allowed the production of sterile all-female triploids. This should have considerable potential for aquaculture.
Article
The purpose of this study was to determine whether triploid salmonid fishes differ from diploids in their hematological and physiological responses to an acute handling and confinement stress, induced by netting fish from their tanks and placing them in a bucket. Blood samples were collected from fish prior to the handling stress and at either 30 min (rainbow trout) or 20 and 40 min (brook trout) confinement in the bucket. Plasma cortisol, glucose and chloride levels, hematocrit, hemoglobin concentration, total blood cell concentrations (erythrocytes and leucocytes), and differential leucocyte concentrations and their relative proportions were measured. As expected, resting blood cell concentrations were significantly lower in triploids than in diploids. In all other respects, triploids showed little difference from diploids in either values prior to the stress or in changes in these values induced by the acute stress. Both diploids and triploids showed a marked stress-induced increase in hematocrit and plasma cortisol and glucose, accompanied by a decrease in lymphocyte concentrations. Other values showed minimal or no change resulting from the stress. Triploid salmonid fishes therefore appear to exhibit a typical acute stress response, as has been well described for diploids.
Article
Triploid and gynogenetic progenies were produced in Atlantic salmon with moderate thermal shocks (26–29°C) applied soon after fertilization. Yields of gynogenetics were high (60–70% of control at start feeding); gynogenetics proved to be all female and could be helpful in the establishment of populations of sex-reversed females to produce all-female livestock in that species. All-triploid groups were also obtained with a wide range of thermal treatments and good survival (66–89% of control at start feeding). Nevertheless, at the age of 2.5 years, triploids displayed lower survival and growth in weight than their control, which may limit their practical interest for aquaculture.
Article
Comparisons of freshwater survival and growth were made between diploid and triploid all-female Atlantic salmon (Salmo salar). All-female fish were produced using sperm from sex-reversed gynogenetic males and triploidy was induced by heat shock. At 4 months post-initiation of feeding the fry were placed in separate replicated rearing tanks for a 16-week early growth trial. Initial and final average weights were 1.3 and 11.0 g/fish, respectively, for diploids, and 1.1 and 11.9 g/fish, respectively, for triploids. Growth rate of triploids was significantly higher than that of diploids (P=0.028). Following the early growth trial the triploids and diploids were pooled in a single large tank and raised until completion of smoltification at 17 months post-initiation of feeding. Average weight at this time was significantly greater for diploids (94 g/fish) than for triploids (76 g/fish) (P<0.00002).
Article
In September 1991 cataracts occurred in two year-classes of triploid Atlantic salmon. The fish showed varying degrees of blindness, were lethargic and became emaciated owing to their inability to feed. The lesions in the lens were mainly in the anterior and posterior cortex and perinuclear areas, the capsule and embryonic nucleus remaining unaffected. Diploid fish of the same year-class did not have cataracts. The origin of the triploid fish, the method of triploidisation, their diet and disease status were investigated, but no predisposing factors could be found to account for the high incidence of cataracts.
Report of the ICES advisory committee on fishery management
  • Anonymous
Growth, survival and smolting rate of triploid Atlantic salmon (Salmo salar) in New Brunswick
  • McGeachy
Report of the working group on the impacts of salmon aquaculture
  • Anonymous
Interactions between salmon culture and wild stocks of Atlantic salmon: the scientific and management issues
  • P Hutchinson