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Comparing salinities of 10, 20, and 30‰ in intensive, commercial-scale biofloc shrimp ( Litopenaeus vannamei ) production systems
Abstract
Minimal-exchange, intensive biofloc aquaculture systems offer a viable means of culturing marine animals at inland locations due to very low rates of water use. Fresh, never-frozen shrimp can be provided to metropolitan markets; however, the cost of artificial salt can be substantial. The purpose of this project was to examine commercial-scale biofloc shrimp production at three different salinities. Nine raceways were randomly assigned to three salinity treatments: 10, 20, and 30‰ (LS, MS, and HS), each treatment contained three raceways operated at 50 m³. The raceways were operated as heterotrophic biofloc systems, with daily additions of sucrose to raise the C:N ratio. Temperature, dissolved oxygen, pH, and salinity were all maintained at consistent levels. Spikes of ammonia and nitrite occurred in all tanks but nitrate remained low, with a peak value of 8.7 mg NO3-N L− 1. There were no significant differences in any shrimp production metric. Mean shrimp growth rate was 1.8, 2.0, and 2.0 g week− 1 in the LS, MS, and HS treatments respectively. Mean feed conversion rate was 1.6, 1.2, and 1.2 in the LS, MS, and HS treatments respectively, and mean final weight ranged from 17.8 to 19.3 g. The only time water was removed from the systems was when settling chambers were emptied, resulting in a total mean water replacement of 5.2% or less per raceway. The mean volume of full strength seawater used to produce shrimp was 104, 159, and 235 L kg− 1 of shrimp in the LS, MS, and HS treatments respectively. Although there were no significant differences in shrimp production metrics between treatments, these values were noticeably lower in the LS treatment due to human error. Operating at the low salinity of 10‰ reduces salt use by about 50% over the MS treatment which implies substantial cost savings for production facilities. This study helps to illustrate the range of salinity options for shrimp production in commercial-scale biofloc systems.
... Generally, there are two routes in inland regions to obtain water sources fitting requirements for a successful culture of L. vannamei, (i) pumping groundwater with a salinity of 1.8-2.6‰ (Samocha et al., 2004), and (ii) adding brine solution or artificial sea salt to freshwater ponds (Ray and Lotz, 2017;Roy et al., 2010). However, culturing a marine species in inland zones would result in adverse effects on the non-saline earth surface, either with utilization of saline groundwater or with addition of artificial sea salt (Avnimelech, 2015). ...
... Form this point of view, BFT makes culture of marine species like L. vannamei in inland zones with minimal negative effects on local ecosystem possible (Avnimelech, 2015). Several studies have also successfully adopted this technology in nursery and grow-out culture of L. vannamei with low salinities of 4-16‰ (Esparza-Leal et al., 2016;Lobato et al., 2019;Luo et al., 2019;Maicá et al., 2012;Moreno-Arias et al., 2017;Ponce-Palafox et al., 2019;Ray et al., 2011;Ray and Lotz, 2017). ...
... As a result, peaks of ammonia and nitrite appear sequentially, and nitrate continuously accumulates. However, less accumulation of nitrate was observed in BFT treatment of the present study, in agreement with observations in other biofloc systems (Browdy et al., 2012;Maicá et al., 2012;Panigrahi et al., 2018;Ray and Lotz, 2017). It is considered that a full nitrification could be established with obvious nitrate accumulation in closed systems with a low C:N (Luo et al., 2020). ...
This study aimed to evaluate the effects of biofloc technology on inputs, costs and wastes discharge during grow-out culture of Litopenaeus vannamei under a low salinity condition. Two systems (water volume 5 m³, salinity 5‰) were designed: biofloc system (BFT) with addition of molasses (C:N 20:1), and clear water system (CW), for a 63-day culture experiment with shrimp juveniles (~0.80 g, 90 shrimp m⁻³). Water quality and zootechnical performance were monitored, and the costs and benefits were estimated. Results showed that the levels of pH (7.75±0.01), carbonate alkalinity (86.6±1.9 mg CaCO3 L⁻¹), biofloc volume (29.1±2.1 mL L⁻¹), total suspended solids (588.7±40.0 mg L⁻¹) and total ammonia nitrogen (1.42±0.12 mg L⁻¹) in BFT treatment were significantly higher than those in CW (7.26±0.07, 61.9±1.2 mg CaCO3 L⁻¹, 1.1±0.7 mL L⁻¹, 75.4±9.4 mg L⁻¹ and 0.62±0.06 mg L⁻¹, P < 0.05). Significantly higher survival rate (100%) and productivity (1.10±0.02 kg m⁻³) were observed in BFT treatment, when compared to those in CW (92.6±3.7% and 0.96±0.01 kg m⁻³, P < 0.05). The total cost in BFT treatment were 9.51±0.55 USD kg⁻¹, significantly lower than that in CW (42.20±0.67 USD kg⁻¹, P < 0.001). The discharge of waste water, salt, ammonia, nitrite and nitrate in BFT treatment decreased 78.9-99.7% compared to that in CW. The resutls indicated that biofloc technology could be adopted for an environment-friendly and cost-effective culture of L. vannamei with a salinity as low as 5.0‰.
... However, culture of this marine species in inland zones might negatively affect the local ecosystem, even under the low salinity condition (Avnimelech, 2015). Recently, biofloc technology has been successfully applied in culture of L. vannamei at a low salinity with minimal or zero water exchange (Lobato et al., 2019;Ray and Lotz, 2017;Ray et al., 2011a), indicating that the environmental effects of culturing this marine species in inland zones would be minimized by adopting this technology (Avnimelech, 2015). ...
... It was reported that the toxicity of ammonia and nitrite to shrimp reinforced with decreasing of salinity (Lin and Chen, 2001;Lin and Chen, 2003;Ray and Lotz, 2017). Furthermore, salinity vibrating towards low levels might change the dynamics and the presence of natural bacteria, and the predominance of specific microorganism groups adapted to the environment established in marine salinity condition (Luis et al., 2018;Morais et al., 2020;Reis et al., 2019), leading to different effectiveness of utilization of added carbon source. ...
... Water for culture experiment with a salinity of approximate 5.0‰ was prepared according to the method of Ray and Lotz (2017), with some modifications. Briefly, artificial sea salt powder (Qianglong corporation, Tianjin, China), and chemical reagents of NaHCO3, KCl, MgCl2·6H2O and CaCl2 (food grade), were added to tap water to make a salinity of ~ 5.0‰, a pH value near 8.0, and a carbonate alkalinity of about 200 mg L -1 CaCO3, with K + , Mg 2+ and Ca 2+ concentrations of about 300, 900 and 300 mg L -1 , respectively. ...
This study aimed to investigate the effects of carbon to nitrogen ratio (C:N) on the water quality and shrimp growth performance during the grow-out culture of Litopenaeus vannamei in the biofloc system under a low salinity condition. Three biofloc treatments with an C:N (contained in the inputted feed and carbon source with the assumption that 75% of the feed nitrogen is excreted) of 8:1 (CN8), 16:1 (CN16) and 24:1 (CN24), respectively, were designed to stocking shrimp juveniles (≈ 0.8 g) at a density of 270 individuals m-3, for a 63-days culture experiment at a salinity of about 5‰. Results showed that in CN8 treatment, the levels of pH (6.9±0.1), carbonate alkalinity (104.0±2.8mg L-1 CaCO3), biofloc volume (4.8±0.9mL L-1) and TSS (327.4±24.4mg L-1) were significantly lower than those in the other two treatments (≥7.6±0.3, ≥157.6±21.6mg L-1 CaCO3, ≥24.1±3.7mL L-1 and ≥508.1±32.3mg L-1, P<0.05); whereas the levels of TAN (7.1±0.9mg L-1), nitrite (14.0±3.6mg L-1) and nitrate (77.0±5.0mg L-1) were significantly higher than those in the other treatments (≤2.0±0.6mg L-1, ≤4.9±3.1mg L-1 and ≤14.7±5.9mg L-1, P<0.05). The zootechnical parameters of shrimp were not significantly different between three treatments (P>0.05), except that the survival rates in CN16 treatment (96.8±2.0%) and CN24 treatment (93.7±4.2%) were significantly higher than that of CN8 treatment (81.5±6.4%, P<0.05). The results indicated that an inputted C:N higher than 16:1 was suitable for the biofloc system with a low salinity of 5‰, with an optimal inferred C:N range of 18.5-21.0:1 for water quality and growth performance.
... This species could also be cultured under low salinity conditions less than 1.0‰, with a trend that will continue to grow globally (Roy et al., 2010). However, culture of this marine species in inland zones would result in adverse effects on local non-saline earth surface ecologically and environmentally (Avnimelech, 2015;Ray and Lotz, 2017;Roy et al., 2010;Samocha et al., 2004). Fortunately, Biofloc technology (BFT) could be used in aquaculture with minimal or zero water exchange, making it possible for culture of marine species like P. vananmei in inland zones with minimal negative effects on local ecosystem (Avnimelech, 2015). ...
... From this point of view, application of BFT could reduce the input and discharge of salt to local ecosystem, during culture of P. vananmei in inland zones. And recently, BFT has been successfully adopted in nursery and grow-out culture of P. vananmei under low salinity conditions (Esparza-Leal et al., 2016;Khanjani et al., 2020;Lobato et al., 2019;Luo et al., 2019;Maicá et al., 2012;Moreno-Arias et al., 2017;Ponce-Palafox et al., 2019;Ray and Lotz, 2017;Ray et al., 2011). ...
... There two biofloc systems with three replicates for each were set up in the present study: the reusing-water system (RS) and the new-water system (NS). In NS, water with a salinity of about 5.0‰ was prepared according to Ray and Lotz (2017), with K + , Mg 2+ and Ca 2+ concentrations of about 300, 900 and 300 mg L − 1 , respectively, by using artificial sea salt powder (Qianglong corporation, Tianjin, China), and food-grade chemical reagents of KCl, MgCl 2 and CaCl 2 ( Table 1). The pH value of water was adjusted to near 8.0 with NaHCO 3 (food grade). ...
This study aimed to investigate water quality, growth performance of Penaeus vananmei postlarvae (PL) and bacterial community in a reusing-water biofloc system under a low salinity condition. PLs (~ stage 15) were stocked in two biofloc systems: the reusing-water system (RS) and the new-water system (NS), at a density of 4000 individuals m−3 for a 28-days nursery experiment at a salinity of 5.0‰, with a C:N of 15:1. Results showed an acceptable growth performance of shrimp in RS that the final body weight and productivity were 0.104 ± 0.014 g shrimp−1 and 0.37 ± 0.05 kg m−3, although those parameters were significantly lower than those in NS (0.138 ± 0.018 g shrimp−1 and 0.48 ± 0.07 kg m−3, P < 0.05). However, the survival rate of shrimp in RS (88.9 ± 4.2%) was not significantly different from that of NS (86.6 ± 6.5%, P = 0.786). The TAN and nitrite levels in RS were 1.90 ± 0.42 and 6.55 ± 0.86 mg L−1, non-significantly higher than those in NS (0.04 ± 0.02 and 0.07 ± 0.01 mg L−1, P ≥ 0.05). Whereas, the levels of total nitrogen (285.5 ± 10.2 mg L−1) and nitrate (24.8 ± 2.7 mg L−1) in RS were significantly higher than those in NS (231.3 ± 6.1 and 4.6 ± 0.4 mg L−1, P < 0.05). The Shannon index of bacterial community in RS (6.22 ± 0.02) was significantly lower than that in NS (7.23 ± 0.02, P < 0.05). The bacterial communities in both systems were dominated by Bacteroidetes (10.64–15.55%), Firmicutes (4.11–9.42%), Planctomycetes (14.43–29.67%) and Proteobacteria (38.73–50.35%) with few ammonia- and nitrite-oxidizing bacteria. The proportions of denitrification bacteria and heterotrophic nitrification-aerobic denitrification bacteria in RS were 0.65 ± 0.07% and 5.73 ± 0.23%, significantly lower than those in NS (9.05 ± 0.15% and 9.26 ± 0.14%, P < 0.05). The results suggested that acceptable growth performance of postlarvae and water quality could be obtained in the reusing-water biofloc system, although the nitrogenous load was slightly high and should be studied next to reduce.
... Shrimp raised in salinity of 15 and 20 ppt had better growth performance (FCR, WGR, and SGR) than those reared in the 10 ppt treatment. This result was also observed by other researchers [13,27,49,53,54]. Therefore, based on those studies and the results of the present study, the optimal salinity for the growout of whiteleg shrimp would be 15-20 ppt. ...
... In this research, shrimp in the three salinities had a survival rate above 90% with no significant difference among treatments; however, Ray and Lotz [53] reported that mortality in lower salinity was higher. This may be because shrimp reared in lower salinity have poor resistance to nitrite toxicity [48]. ...
... However, filter bags are commonly used to prevent excess biofloc which can clog plants root or irritate the gills of aquatic animals [26]. That may be the reason why the concentrations of TSS and VSS in the present study were lower than other published research [26,52,53,64,65]. In addition, the short cultivation time of the present study may be another reason for the low concentrations of TSS and VSS. ...
... In China, L. vannamei shrimp culture has been practiced in 16 of 20 inland provinces (Bureau of Fisheries, Ministry of Agriculture PRC, 2020). However, this widespread practice in inland zones might indicate a huge risk on local non-saline earth surface ecologically and environmentally due to adverse effects of salt added in the fresh culture waterbody (Ray and Lotz, 2017;Roy et al., 2010). ...
... Recently, biofloc technology (BFT) has been developed for managing a good water quality in intensive aquaculture with minimal or zero water exchange requirement, making culture of marine species like L. vannamei in inland zones possible with minimal effect on local ecosystem (Avnimelech, 2015). Several studies have been conducted on L. vannamei nursery and grow-out culture with BFT under salinities of 4-16‰ (Esparza-Leal et al., 2016;Lobato et al., 2019;Luo et al., 2019;Maicá et al., 2012;Moreno-Arias et al., 2017;Ray and Lotz, 2017;Ray et al., 2011). ...
... Other factors would also affect the utilization efficiencies of carbon source in the biofloc system, such as predominant bacteria (Becerra-Dorame et al., 2012;Xu et al., 2016), temperature (Ponce-Palafox et al., 2019), and salinity (Esparza-Leal et al., 2016;Maicá et al., 2012;Ray and Lotz, 2017), suggesting that the selection of carbon source used for growing bioflocs is of prime importance for a certain culture condition (Martínez-Córdova et al., 2015;Wei et al., 2020). However, knowledge about effects of carbon sources is limited for the biofloc system rearing L. vannamei with a low salinity. ...
This study aimed to investigate the effects of different carbon sources on water quality and growth performance of Litopenaeus vannamei in the biofloc system under a salinity condition as low as 5‰. Three biofloc treatments with glucose (Glu), molasses (Mol) and starch (Sta) as carbon source, respectively, were designed to stocking shrimp juveniles (0.81 ± 0.02 g) at a density of 90 individuals m⁻³ for a 63-days culture experiment. Results showed that there was no significant difference on shrimp performance and water quality between Glu treatment and Mol treatment. The final mean body weight, weekly increment rate of body weight, specific growth rate, feed efficiency rate, productivity and survival rate of shrimp in Glu and Mol treatments, were all significantly higher than those in Sta treatment (P < 0.05). Significantly higher pH and carbonate alkalinity (P < 0.05), but significantly lower levels of total ammonia nitrogen, nitrite and nitrate (P < 0.05), were also found in Glu and Mol treatments, when compared to those in Sta treatment. The results indicated that in the biofloc system with a low salinity in the present study, soluble glucose and molasses are good carbon sources for grow-out culture of L. vannamei shrimp.
... Inland aquaculture production of marine species is growing worldwide (Ray and Lotz, 2017a;Ponce-Palafox et al., 2019). To support this expansion, research focusing on marine shrimp cultured in low-salinity water has been carried out. ...
... Brackish water, with a salinity of more than 1 ppt, may be appropriate for shrimp farming and is currently practiced in a number of countries such as the United States of America, Thailand, China, and Australia (Roy et al., 2010). The possibility of producing L. vannamei in brackish BFT systems in inland areas emerges as an interesting alternative to traditionally higher cost coastal culture areas and allows for production closer to consumers in urban centers (Browdy and Moss, 2005;Ray and Lotz, 2017a). Additionally, using low-salinity systems may reduce the costs of imported seawater or artificial sea salts (Ray and Lotz, 2017a). ...
... The possibility of producing L. vannamei in brackish BFT systems in inland areas emerges as an interesting alternative to traditionally higher cost coastal culture areas and allows for production closer to consumers in urban centers (Browdy and Moss, 2005;Ray and Lotz, 2017a). Additionally, using low-salinity systems may reduce the costs of imported seawater or artificial sea salts (Ray and Lotz, 2017a). Evidence that whiteleg shrimp can grow and survive in brackish water has already been reported (Samocha et al., 2004;Ray and Lotz, 2017b;Pinheiro et al., 2020). ...
A study was conducted to evaluate the sensorial attributes and zootechnical performance of whiteleg shrimp (Litopenaeus vannamei) juveniles cultured in biofloc technology (BFT) with varying water salinities and proteinous feed. The experiment was conducted at two salinity levels viz., 5 ppt and 30 ppt each with two different proteinous feeds viz., 25% and 35% crude protein (CP), in a completely randomized factorial experimental design. Shrimp juveniles (average weight: 1.07 g) were stocked uniformly at the density of 233 shrimp m⁻³ in sixteen 60-L experimental tanks and reared for nine weeks. At the end of culture, all shrimps were harvested from the tanks and zootechnical parameters were recorded. The sensorial attributes viz., aroma, color, flavor, texture, and overall acceptance of shrimps reared in BFT under the tested treatments and in traditional earthen pond culture system were compared. In terms of zootechnical parameters, survival was similar among all treatments. The shrimp growth and productivity were significantly affected by either salinity and protein levels of feed. The same trend was observed for the feed conversion ratio and protein efficiency ratio. The highest shrimp growth (final weight: 4.08 g) was achieved in 30 ppt water with 35% CP. The sensorial attributes of shrimp were similar in all experimental treatments including those reared in traditional earthen pond. The results suggested that 30 ppt of water salinity and 35% of dietary crude protein promoted superior shrimp performance as compared to 5 ppt and 25% CP. Additionally, the current study revealed that sensorial attributes of L. vannamei cultured in BFT did not change regardless of the salinity (5 ppt and 30 ppt) and/or the dietary crude protein (25% and 35% CP), and was comparable to those reared in traditional earthen ponds.
... Shrimp raised in salinity of 15 and 20 ppt had better growth performance (FCR, WGR, and SGR) than those reared in the 10 ppt treatment. This result was also observed by other researchers [13,27,49,53,54]. Therefore, based on those studies and the results of the present study, the optimal salinity for the growout of whiteleg shrimp would be 15-20 ppt. ...
... In this research, shrimp in the three salinities had a survival rate above 90% with no significant difference among treatments; however, Ray and Lotz [53] reported that mortality in lower salinity was higher. This may be because shrimp reared in lower salinity have poor resistance to nitrite toxicity [48]. ...
... However, filter bags are commonly used to prevent excess biofloc which can clog plants root or irritate the gills of aquatic animals [26]. That may be the reason why the concentrations of TSS and VSS in the present study were lower than other published research [26,52,53,64,65]. In addition, the short cultivation time of the present study may be another reason for the low concentrations of TSS and VSS. ...
The effect of salinity on the growth performance of whiteleg shrimp (Litopenaeus vannamei) and three halophyte plants, red orache (Atriplex hortensis), okahijiki (Salsola komarovii), and minutina (Plantago coronopus), in a marine aquaponic system with biofloc was evaluated in this study. The experiment was conducted for 4 weeks, and the three treatments were 10, 15, or 20 ppt (parts per thousand). The growth performance of the shrimp and the three halophytes were affected by the salinity. Compared to the shrimp reared in 10 ppt, those reared in 15 and 20 ppt had higher final weight, weight gain rate (WGR), and specific growth rate (SGR), and lower feed conversion ratio (FCR). The results from shrimp raised in 15 ppt were 2.0 ± 0.1 g, 89.9 ± 2.2%, 2.3 ± 0.0%, and 1.5 ± 0.0, respectively, and those in 20 ppt were 2.0 ± 0.1 g, 93.9 ± 5.4%, 2.4 ± 0.1%, and 1.4 ± 0.1, respectively. On the other hand, the growth performance and nutrient content in halophyte plants decreased with the increasing salinity. In general, the three halophyte plants had better results in the 10 and 15 ppt treatments than those in 20 ppt. Therefore, the salinity of 15 ppt was suggested as the optimal condition for the integrated cultivation of whiteleg shrimp and the three halophytes in marine aquaponics. Additionally, they are compatible species for the development of marine aquaponics.
... The effects of environmental factors, such as the temperature and salinity of the water, on the acclimation, growth and production of the P. vannamei have been studied in recirculation aquaculture systems (Ogle et al., 1992;Ponce-Palafox et al., 1997;Laramore et al., 2001;McGraw et al., 2002;Decamp et al., 2003;Hernandez et al., 2006;Zhang et al., 2006;Jayasankar et al., 2009;Maicá et al., 2014). However, the effects of the two above-mentioned factors on the growth and survival in the biofloc system have only been determined independently for the temperature (Souza et al., 2014) and salinity (Esparza-Leal et al., 2016;Ray and Lotz, 2017). It is very important to understand the behavior and to establish an optimal sustained growth zone of the two factors selected under the biofloc system. ...
... Three replicate tanks were assigned to each of the following temperatures and salinities: 24, 28 and 32°C, and 10, 20 and 30 g L −1 , respectively. The selected salinities were similar to those used by Ray and Lotz (2017) in the biofloc system. The water in the 28-32°C treatment tanks was heated using submerged heaters with thermostats. ...
... The effect of salinity on the water quality in the current study was also similar to that reported in biofloc systems (Souza et al., 2016;Ray and Lotz, 2017;Mendoza-López et al., 2017) and the concentrations were within the reported range (Mendoza-López et al., 2017). The main effect was on the pH, alkalinity, nitrate, TSS, and SS, which rise with increasing the salinity, but the relationship was inversed for oxygen and nitrites (Esparza-Leal et al., 2016). ...
This study aimed to evaluate the effect of temperature-salinity interaction on physico-chemical parameters, plankton composition, performance growth, and survival of shrimp Penaeus vannamei raised in intensive nursery production with biofloc system and zero-water exchange, by means of the response surfaces analysis. A 3 × 3 factorial experiment was conducted to determine the effects of temperature (24, 28, and 32 °C) and salinity (10, 20, and 30 g L⁻¹) on water quality, performance, growth, and survival of Penaeus vannamei with the initial wet body weight of 0.004 ± 0.001 g. The experiment lasted for 4 weeks. The temperature and salinity, independent and their interaction, had a differential effect on the studied parameters. At higher temperatures, there was a significant tendency to increase the concentration of total ammonia‑nitrogen, nitrite, nitrate, total suspended solid and sedimentable solid, and lower dissolved oxygen concentration was found. Chlorophyta and rotifers were the most dominant groups of phytoplankton and zooplankton in the studied biofloc, respectively. The results showed that all shrimp had survivals above 84.5% at temperatures of 24–28 °C. The survival decreased with increasing the temperature from 28 to 32 °C. All growth parameters increased with the increase of salinity in the 24–28 °C temperature range, reaching a maximum value at 32 °C and 20 g L⁻¹. In contrast, FCR decreased in response to increasing temperature within the tested salinity. The results of the response surface methodology demonstrated the effects of temperature-salinity interaction on the growth and survival of the postlarvae and early juveniles of shrimp P. vannamei in the biofloc system. The optimum conditions to obtain the maximum specific surface area of final weight, feed conversion ratio, specific growth rate, weekly growth gain, productivity, and survival were temperature of 27.25 °C and salinity of 25.5 g L⁻¹, which were derived from the optimization approach. The results of this study help illustrate the range of temperatures-salinity options of shrimp raised for intensive nursery production in commercial-scale biofloc systems.
... On the other hand, it also promotes the development of inland aquaculture, providing fresh shrimp for inland areas that cannot otherwise obtain such commodities [22]. However, the cultivation of L. vannamei in inland areas may have adverse ecological and environmental impacts on the local nonsaline earth surface [23,24]. ...
... Fortunately, using BFT in inland areas to culture L. vannamei can necessitate little or no change in water usage during the farming process, thus reducing the discharge of salt and minimizing the impact on the local ecological environment [23]. At present, several studies successfully applied BFT to low-salinity L. vannamei aquaculture systems, but these studies primarily focused on growth performance [25][26][27][28][29], amino acid and fatty acid compositions [30], and yield [24,31] of L. vannamei as well as the compositions of biofloc [32]. However, there are few research reports on digestive enzyme activity, antioxidant levels, or immune status of L. vannamei in the BFT culture system under low-salinity conditions [30]. ...
Biofloc technology (BFT) culture systems based on low salinity can meet the needs of shrimp growth and environmental protection, thus having potential application. To evaluate the effects of BFT on water quality, the microbial community, growth, digestive enzyme activity, and antioxidant and immune status of Litopenaeus vannamei under low salinity conditions, a four-week experiment was conducted in a BFT culture system (C/N ratio of 12: 1) with three salinity conditions: 5.0‰ (S5 group), 10.0‰ (S10 group), and 15.0‰. The results showed that water quality parameters were all within the range suitable for the culture of L. vannamei. There were no significant differences in growth parameters such as final weight or specific growth rate. Muscle moisture, crude protein, and crude lipid contents of L. vannamei did not differ among groups (p > 0.05). In addition, intestinal amylase and trypsin activities in the S5 group significantly increased (p < 0.05). In the S15 group, the superoxide dismutase activity and total antioxidant capacity in the serum and hepatopancreas of L. vannamei, as well as serum catalase, acid phosphatase, and alkaline phosphatase activities, markedly increased (p < 0.05). The microbial diversity (Shannon and Simpson indices) and richness (Chao1 and ACE indices) were higher in the S5 group than in the S15 group. Our findings indicated that although the shrimp in BFT systems with a salinity of 5‰ had lower antioxidant and immune levels, the digestive enzyme activity as well as the gut microbial diversity and richness improved compared to other groups, suggesting the possibility of culturing L. vannamei in low-saline areas with BFT systems.
... In intensive shrimp production in artificial seawater, salinity plays a crucial role in maintaining financial returns. Salinity affects two factors: the cost of operation, which is directly proportional to salinity, and the production risks, which are inversely proportional, as nitrogen compound toxicity increases with reduced salinity (Alves Neto et al., 2019;Ramirez-Rochin et al., 2016;Ray and Lotz, 2017).The financial returns of these systems are also preserved through the adoption of culture systems based on water reuse, such as biofloc technology (BFT). BFT is developed by using the microbial loop, which promotes the cycling of nitrogenous compounds within the production tank itself (Ebeling et al., 2006;Ray and Lotz, 2017;Wasielesky Jr. et al., 2006). ...
... Salinity affects two factors: the cost of operation, which is directly proportional to salinity, and the production risks, which are inversely proportional, as nitrogen compound toxicity increases with reduced salinity (Alves Neto et al., 2019;Ramirez-Rochin et al., 2016;Ray and Lotz, 2017).The financial returns of these systems are also preserved through the adoption of culture systems based on water reuse, such as biofloc technology (BFT). BFT is developed by using the microbial loop, which promotes the cycling of nitrogenous compounds within the production tank itself (Ebeling et al., 2006;Ray and Lotz, 2017;Wasielesky Jr. et al., 2006). Water reuse also mitigates the environmental impacts caused by the discharge of effluents from shrimp farms in continental areas, such as water and soil salinization, eutrophication of water, and biological contamination of adjacent farms (Godínez-Siordia et al., 2011;Krummenauer et al., 2014). ...
... However, the culture of this marine species in inland zones might negatively affect the local ecosystem, even under low salinity condition (Avnimelech, 2015). Recently, biofloc technology has been successfully applied for culturing L. vannamei at low salinity (4-16‰) with minimal or zero water exchange (Lobato et al., 2019;Ray & Lotz, 2017), indicating that the environmental effects of culturing this marine species in inland zones would be minimized by adopting this technology (Avnimelech, 2015). ...
... It was reported that the toxicity of ammonia and nitrite to shrimp increases with salinity decreasing (Lin & Chen, 2001;Lin & Chen, 2003;Ray & Lotz, 2017). Furthermore, salinity vibration towards low levels might change the dynamics and the presence of natural bacteria, and the predominance of specific microorganism groups adapted to the environment established in marine salinity condition (Luis et al., 2018;Morais et al., 2020;Reis et al., 2019), which might result in shifting of microbial utilization effectiveness on exogenous carbon source in the biofloc system. ...
This study aimed to investigate the effects of carbon‐to‐nitrogen ratio (C:N) on water quality and shrimp growth performance during the grow‐out culture of Litopenaeus vannamei in a biofloc system under a low salinity condition. Three biofloc treatments with a C:N (contained in feed and exogenous carbon source with the assumption that 75% of the feed nitrogen is excreted) of 8:1 (CN8), 16:1 (CN16) and 24:1 (CN24), respectively, were designed to stocking shrimp juveniles (~0.8 g shrimp−1) at a density of 270 individuals m−3, for a 63‐day culture experiment at a salinity of about 5‰. Water parameters were monitored, and zootechnical indices were determined in the three treatments. Results showed that in CN8 treatment, pH, carbonate alkalinity, biofloc volume and TSS were significantly lower (p < 0.05), whereas TAN, nitrite and nitrate were significantly higher, than those in the other two treatments (p < 0.05). The zootechnical parameters of shrimp were not significantly different among the three treatments (p > 0.05), except that the survival rates in CN16 treatment (96.8 ± 2.0%) and CN24 treatment (93.7 ± 4.2%) were significantly higher than that of CN8 treatment (81.5 ± 6.4%, p < 0.05). Regression analysis revealed that the optimal C:N range for pH, SVI (sludge volume index), TAN, nitrate and survival rate was 20.5:1, 18.5:1, 21.0:1, 20.8:1 and 18.6:1. The results suggested that the C:N higher than 16 were suitable for culturing L. vannamei in the biofloc system with a salinity of 5‰, with an optimal range of 18.5–21.0:1.
... The clarification time was not sufficient to efficiently remove the particulate biofloc volume. Ray and Lotz (2017) presented mean values of 7 ± 1 mL/L in salinity 10‰ and 9 ± 1 mL/L in salinity 30‰ for SetS since they maintained the clarifier (settling chambers) with a continuous flow rate of 15 L/min, except once a week in which the water flow was interrupted for 1 hour to allow the complete sedimentation of the biofloc particles. ...
... This difference may be related to cellular plasmolysis at higher salinities, decreasing the number of active bacteria that consume alkalinity. However, Ray and Lotz (2017) did not find a significant difference in alkalinity between salinity of 10‰, 20‰, and 30‰ in L. vannamei production using BFT. The alkalinity values in the present study did not negatively affect the shrimp, because, in both treatments, they were higher than 75 mg/L, as described by Furtado et al. (2015). ...
The study aimed to characterize the dynamics involved in the water quality parameters in a biofloc system (BFT) during the super-intensive cultivation of Litopenaeus vannamei using two levels of artificial brackish water. The test was designed with two salinity levels, T16 (16‰) and T8 (8‰), with 4 replicates, and 250 shrimps/m² by 60 days, water analysis and animal performance were studied in each treatment. No significant differences were observed between the two salinities for biochemical oxygen demand (BOD5), total chemical oxygen demand (CODt), and fixed suspended solids (FSS). Using CODt/BOD5, it was possible to identify the water biodegradability and manage the concentration of organic and inorganic matter in the medium. Filtered chemical oxygen demand (CODf) was used to monitor the dissolved organic matter, which was higher in T16. Carbohydrate (molasses) did not control total ammonia reaching in T8 = 1.16±0.64 mg/L. This organic matter addition reduced the growth of chemoautotrophic nitrifying bacteria and interfered in the nitrogen dynamics. Regarding total solids and suspended solids, there was a significant difference between treatments, except for FSS. Dissolved oxygen (DO) and oxygen saturation (sO2) were significantly different between the treatments. The maintenance of a more neutral pH and greater alkalinity were observed, with significant differences between the treatments throughout the whole cultivation. Regarding the shrimp growth performance, the high salinity presented more weight gain, specific growth rate, feed conversion and final biomass, and lower mortality then lower salinity. These results showed that shrimps presented a higher performance in salinity 16‰.
... The data normality and homogeneity were checked by applying the Shapiro-Wilk's test and Levene's test for the equality of variances (p > .05). The data that were not normal and percent data were log 10 and arcsine transformed, respectively (Ray & Lotz, 2017). And then, one-way analysis of variance (ANOVA) followed by Duncan test carried out to determine significant differences among treatments, using probiotic supplementation as factor. ...
... And then, one-way analysis of variance (ANOVA) followed by Duncan test carried out to determine significant differences among treatments, using probiotic supplementation as factor. A repeated-measures (RM) ANOVA followed by Tukey's test was used for water quality parameters analysis, and one-way ANOVA was applied to reveal the differences among study groups at each sampling day (Ray & Lotz, 2017;Ren, Li, Dong, Tian, & Xue, 2019). The data for the challenge test were subjected to paired-samples t test to reveal the significant differences in parameters before and after LPS injection. ...
The present research explored the effects of Bacillus subtilis on water quality, growth, immune responses, endotoxemia, and protection against lipopolysaccharide (LPS) damages in Nile tilapia Oreochromis niloticus under biofloc system. B. subtilis was added at 0, 1, 2, 3, and 4 grams (1.19×108 CFU g-1) per kg of basal diet, named T1 (control), T2, T3, T4, and T5, respectively, and fed to fish (14.82±0.42g) for 50 days. The concentrations of TAN, NO2, and NO3 were significantly reduced and fish fed probiotics displayed significantly better growth performances versus the control, concomitantly with significantly enhanced activities of digestive enzymes. They also showed significantly declined serum glucose and cholesterol vice versa significantly improved immune responses (total protein, albumin, globulin, lysozyme, alternative complement, protease, immunoglobulins, alkaline phosphatase, and respiratory burst), antioxidant capacity (superoxide dismutase, total antioxidant capacity, malondialdehyde), and skin mucus parameters (total protein, lysozyme, alternative complement, protease, immunoglobulins). Meanwhile, significantly lower endotoxin (LPS) concentrations were detected in the intestines and serum of fish fed probiotics. LPS challenge induced profound oxidative stress and impaired immune responses. Interestingly, probiotic alleviated LPS-induced damages and restored mentioned parameters. In conclusion, B. subtilis effectively enhanced fish production, immunity, and protection against LPS-induced damages in tilapia under biofloc system.
... Biofloc-based systems have been developed for intensive shrimp culture in recent years (Avnimelech, 2015;Bossier and Ekasari, 2017;Browdy et al., 2012;Samocha et al., 2017), with remarkable success for L. vannamei (Ray et al., 2010;Ray and Lotz, 2017;Samocha et al., 2017). The system is characterized by developing dense microbial biomass in the water to remove toxic nitrogen species such as ammonia and nitrite under limited or zero water exchange conditions (Ebeling et al., 2006;Ray et al., 2011;Xu et al., 2016). ...
... Besides, acceptable water quality and high shrimp survival were obtained under all the three feeding frequencies. These results are comparable to practical efficiency of L. vannamei culture in biofloc-based production systems (Ray and Lotz, 2017;Somacha et al., 2017). Significant effects obtained in this small-scale biofloc-based system under the experimental conditions may also hold true for commercial culture of L. vannamei, which require further test to confirm though. ...
An eight-week feeding experiment was conducted to investigate the effects of daily feeding frequency on the growth, feed utilization, digestive enzyme activity and body composition of Litopenaeus vannamei juvenile reared in biofloc-based zero-exchange intensive culture systems. The experiment was carried out in twelve tanks with 800 L of biofloc-rich water. Juvenile shrimp (1.52 ± 0.37 g) were stocked into tanks at 240 shrimp tank⁻¹ (300 ind m⁻³). Three feeding frequencies of three, six, twelve times were evenly set in the 24 h of a day for experimental groups of F3, F6, F12 respectively. Each group had four randomly assigned tanks, and the shrimp were cultured for eight weeks with the same daily ration based on the monitoring of feeding trays in F3 group. During the experiment, all the monitored water quality parameters were maintained within acceptable ranges for shrimp culture. At the end of the experiment, the shrimp survival rate was higher than 89.03% in all the three groups. Notably, with the increase of daily feeding frequency from three times to six and further to twelve, significant differences were found as follows: (1) the final weight, growth rate and yield of the shrimp increased; (2) the feed conversion rate decreased while the protein efficiency ratio and protein productive value increased; (3) the specific activities of protease and amylase in the stomach of the shrimp and the specific activity of lipase in the digestive gland increased; (4) the crude protein content of the whole body of the shrimp increased while the moisture content decreased. Taken together, these results demonstrate that daily feeding frequency can affect the growth, feed utilization, digestive enzyme activity and body composition of L. vannamei juvenile reared in biofloc-based zero-exchange intensive systems. Distributing a controlled ration of daily feed at frequent times during 24 h of a day is beneficial for the growth, feed utilization, nutrient digestion, and protein deposition of L. vannamei in biofloc-based systems under controlled conditions.
... The conversion of nutrient waste resulted in a low concentration of toxic compounds, in particular ammonia, in the culture system, thus reducing the requirement of water exchange and improving the water use efficiency. Aside from its beneficial effects on maintaining a low concentration of toxic compounds, the application of biofloc technology has also been reported to bring about some positive effects on the growth performances, immune systems, survival, disease resistance, and feed nutrient utilization of some aquaculture species including Nile tilapia (Perez-Fuentes et al., 2016;Ray and Lotz, 2017;Menaga et al., 2019;El-Hawarry et al., 2021). An efficient biofloc system is determined by the balance between the conversion rate of nutrient waste into microbial biomass and the nutrient utilization of the biofloc generated in the system by the cultured organisms (Avnimelech, 2007;Ray et al., 2011). ...
The accumulation of biofloc in a rearing media that may bring about some adverse effects on the cultured fish, can be addressed by using a settlement tank. This study aimed to compare the production performance and flesh quality of red tilapia Oreochromis sp. in biofloc systems with and without a settlement tank. This study comprised of two treatments, i.e. biofloc system with settlement tank (Bioras) and biofloc system without settlement tank (Biofloc), each maintined in triplicates. Fish was reared in outdoor tarpaulin tanks with a diameter of 3 m and a height of 1.2 m, which were filled with about 5 m³ of water. Tilapia with an initial average weight of 100 g was cultured at an initial density of 5 kg m⁻³ for 112 days with a partial harvest conducted on day 42. The fish was fed with a commercial diet containing 30.5% crude protein to apparent satiation twice a day. The results showed that the production performance of red tilapia in Bioras (75 kg) was higher than that of the conventional biofloc system (70 kg). Mild deformities and limited parasite infestation were observed in the gills of the fish housed in the Bioras system. The fish quality was similar between the treatments, except for the hardness (8.4 kgf), gumminess (3.4 kgf), and chewiness (1.8 kgf), which was higher in the fish housed in the conventional biofloc system. The increase in fish growth in Bioras system could not compensate the increase in cost for the investment and operation of the settling tank, which was about 17% higher in the Bioras system. In conclusion, the present study confirmed that the addition of a settlement tank can be beneficial in controlling biofloc biomass and could improve the growth performance, but not yet profitable for red tilapia commercial production.
... L. vannamei is a euryhaline shrimp species with a salinity tolerance range of 0.5-78 ‰ (11,12). Salinity is a crucial environmental factor for aquatic animal reproduction, growth, development, and survival (13)(14)(15). In general, L. vannamei could effectively maintain osmotic pressure and ion regulation under different salinities to adapt to the environment (16). ...
The shortage of fishmeal (FM) resources limits the healthy development of aquaculture. Developing new protein sources to replace FM in aquatic feeds is an effective measure to alleviate this situation. However, the application effect of new protein sources is greatly affected by water salinity, which is an important parameter of aquaculture. In this study, the growth, disease resistance, and intestinal digestion, immunity, and microbiota structure of Litopenaeus vannamei (initial weight: 0.38 ± 0.01 g) fed on Clostridium autoethanogenum protein (CAP) or not at three different water salinities (15 ‰, 30 ‰, and 45 ‰) were compared, aiming to explore the effects of dietary CAP on shrimp when suffering different salinity stresses. The results showed that the growth performance, feed utilization, and survival rate (SR) after pathogen challenge of L. vannamei could be significantly improved by dietary CAP when compared with the control at the same salinity and they were also significantly affected by salinity changes when L. vannamei was fed on the same protein source. With the increase in salinity, obvious upregulation was observed in the activities and gene expression of digestive enzymes both in L. vannamei fed on FM and CAP, with significantly higher levels in L. vannamei fed on CAP than in those fed on FM at the same salinity. Meanwhile, the expression levels of immune genes in the CAP group were significantly higher than those in the FM group at different salinities. The intestinal microbiota analysis showed that CAP could increase the relative abundance of beneficial bacteria and decrease the relative abundance of harmful bacteria in the intestine of L. vannamei at the phylum, family, and genus levels, and it was more affected by salinity changes when compared with FM. Besides, the changes in salinity and protein sources led to different changes in the intestinal microflora function of L. vannamei. In sum, this study indicated that CAP could improve the growth, disease resistance, digestive capacity, and intestinal microflora of L. vannamei with a much more intense immune response and enhance its ability to cope with salinity stress.
... This increase is closely linked to P. vannamei farming, as the species can tolerate a wide saline gradient (0.5 to 60 g L -1 ), enabling culture in both oligohaline and hypersaline waters (Davis et al. 2005;Esparza-Leal et al. 2010;Chong-Robles et al. 2013;Jaffer et al. 2019). However, the considerable variation in the ionic composition of water among different farming sites (Boyd and Thunjai 2003;Valenzuela-Madrigal et al. 2017) and the lack of information on the performance of P. vannamei in intensive and super-intensive systems with different ionic profiles (Ray and Lotz 2017) pose challenges to farming in low-salinity systems. There is also a lack of knowledge on how the ionic composition of the water can limit the productive potential in different regions (Valenzuela-Madrigal et al. 2017). ...
The aim of the present study was to evaluate the efect of diferent ionic compositions
in low-salinity water on the growth and proximate composition of Penaeus vannamei
reared in the synbiotic system. A 56-day trial (300 shrimp m-3) was conducted in 60-L
units with a completely randomized experimental design involving three treatments (each
with three repetitions): Control — seawater diluted to salinity ~2.7 g L−1; T1 — seawater
diluted to salinity~2.7 g L−1 with Ca:Mg:K ratio adjustment (1:3:1); and T2 — seawater diluted to salinity ~2.7 g L−1 with Mg2+ adjustment. The shrimp survival rate varied
from 53.7 to 81.48%, shrimp (initial weight=0.42±0.1 g) reached a fnal weight ranging from 3.70±0.07 to 4.72±0.09 g and an average yield ranging from 0.61±0.14 to
1.22±0.06 kg m−3, with signifcant diferences among the treatments. The best overall growth was found in the T2 treatment. The T1 treatment had the signifcantly lowest results, which may have been due to reduction in the Na:K ratio (Control=27.39;
T2=29.03; T1=19.55) due to K+ corrections. Low concentrations of nitrogen compounds were found due to the synbiotic fertilization and substrate composed of Anomalocardia brasiliana shells that work as substrate for bacteria and a source of calcium
carbonate. No signifcant diferences in proximate composition were found among the
treatments. A diference in the ash content of the microbial focs was found among treatments, with a higher percentage in the T1 treatment compared to the Control and T2 treatments. The present results indicate that total alkalinity close to 90 mg CaCO3 L−1 and the Na:K ratio close to 28:1 produced conditions that did not limit the growth of P. vannamei in low-salinity water with a synbiotic system.
... In the past decade, biofloc technology (BFT) aquaculture systems have been demonstrated to permit high stocking loads of tilapia and shrimp and to be one of the most useful limited-discharge aquaculture production technologies. [5][6][7][8][9][10][11][12] BFT incorporates uneaten feed and faeces into the water instead of removing them. 13 In BFT systems, ammonia resulting from the degradation of uneaten feed and faeces or the excretion of farmed animals is assimilated by heterotrophic bacteria by manipulating the carbon/nitrogen ratio (C/N) instead of converting ammonia to nitrate, the key process controlling ammonia in RASs. ...
The abundance of nitrogen compounds, phosphorous compounds and organic matter in biofloc technology (BFT) aquaculture systems creates an ideal medium for increasing microbial communities and load. The abundance of microbial DNA found in BFT aquaculture systems is hypothesised to be among the greatest in current aquaculture systems. Several factors mediate the bacterial diversity, relative abundance and dynamics in BFT systems. This review focusses on the bacteria in BFT aquaculture systems, their role as food for animals present in the culture and their various relationships with major nutrients. The analytical techniques available for determining bacterial integrity and function are reviewed along with the factors that affect microbial community structure, water quality and production performance. Future investigations to characterise bacteria in BFT aquaculture systems and their roles and mediating factors are suggested.
... Shrimp farming production is one of the fastest-growing segments of the world agriculture with a forecast of the compound annual growth rate in the period 2017-2021 being 4.8 to 5.4% [1,2]. Undoubtedly, shrimp farming management should be based on a systems approach including the application of different materials to provide high productivity and quality and minimize negative impact on the environment [3,4]. To develop an efficient management strategy, understanding of the factors that maintain and control shrimp production is required. ...
In order to increase shrimp production and minimize detrimental environmental impacts of aquaculture, the maintenance and regulation of the growth and composition of phytoplankton communities and nutritional balance are critical. Silicon (Si) is an essential nutrient for diatoms and other types of microorganisms, but the information about the Si impact on their growth is extremely scarce. Monosilicic and polysilicic acids were tested in several shrimp cultivation systems in Jiangsu Province, China. In pond waters, the concentrations of monosilicic and polysilicic acids were sharply reduced by 36-95% and 35-75%, accordingly, as compared with those in supply water sources. The microbial cell abundance was strongly dependent on monosilicic acid. In laboratory experiments, monosilicic acid added to pond water or probiotic solutions at 1- and 2-mM Si had a significant positive effect on cell abundance. Over three days, the concentrations of monosilicic acid decreased by 81 to 91% in pond water and by 11 to 24% in probiotic solution. In probiotic solutions, the degree of polymerization of silicic acid was more intensive than that in shrimp pond waters. The data obtained demonstrates the importance of systematic studies related to the functions of Si in shrimp aquaculture.
... Water with a salinity of 5.0‰ for culture experiment was prepared according to Ray and Lotz (2017), with some modifications. Briefly, artificial sea salt powder (Qianglong corporation, Tianjin, China), and food grade chemical reagents of KCl, MgCl2 and CaCl2 were added to tap water to make a final salinity of 4.96‰ (~5.0‰), with K + , Mg 2+ and Ca 2+ concentrations of 292, 934 and 318 mg L -1 , respectively. ...
This study aimed to investigate the bacterial composition and inferring function profiles in the biofloc system rearing Litopenaeus vannamei postlarvae (PL) at a low salinity condition. PL (~ stage 15) were stocked in four parallel tanks filled in water with a salinity of 5.0‰ at a density of 4000 individuals per m3 for a 28-days culture experiment, during which glucose was added as carbon source with a C:N of 20:1. At the end of experiment, water was sampled from each tank and pooled to extract microbial DNA for high-throughput sequencing of V3-V4 region of 16S rRNA gene. Results showed that the bacterial community at 28 d was dominated by phyla of Proteobacteria (45.8%), Bacteroidetes (21.1%), Planctomycetes (13.5%), Chlamydiae (10.3%) and Firmicutes (6.8%). A proportion of 81% inferring KEGG functions of this bacterial community associated with metabolism. Among functions relating to nitrogen metabolism, 48.5% were involved in the conversion of ammonia to glutamate, but the proportion of those involved in transformation among ammonia, nitrite and nitrate was 18.0% in total, inferring higher protein-synthesis but lower inorganic nitrogen-transformation capacities of the bacterial community. At the same time (28 d), high levels of total nitrogen (231.3±6.0 mg L-1) and biofloc (127.0±63.0 mL L-1), but low concentrations of ammonia (0.04±0.01 mg L-1), nitrite (0.2±0.1 mg L-1) and nitrate (12.9±2.5 mg L-1) were observed. The results supply a novel insight for understanding the function of bacterial community in the biofloc system nursing L. vannamei PL at a low salinity.
... Therefore, studies are needed to reduce salt costs in these systems to be constructed based on BFT. In a study conducted for this purpose, BFTbased shrimp culture was carried out in raceway pools for three salinity ratios as ‰10, ‰ 20, and ‰30 (Ray and Lotz 2017). Growth performances and FCR did not differ significantly between treatments. ...
The aquaculture sector, which responds to alternative food supply, continues to grow exponentially with each passing day. For this reason, there is a need for manpower to meet the increasing workload in aqua-culture facilities. As in every sector, occupational health and safety is quite important for employees in aquaculture. The current study focused on case scenarios that may occur in an integrated trout farming facility. Expert opinions for a total of 79 different case scenarios were evaluated. The case scenarios ana-lyzed with the 5x5 matrix method showed that high-risk cases can occur in the facility-wide, culture tanks, toilets and feed storage. The highest number of risks for all case scenarios is in the medium risk category. In the medium risk category, there is a potential for employees to encounter consequences such as death and loss of limbs, especially if the case scenarios foreseen for the facility are realized. The lowest risk averages for case scenarios collected in 4 clusters according to processes are dining hall and locker rooms.
... thousand metric tons) and they display rapid growth (FAO, 2006), high market price (Ross et al., 2017) and strong global demand (FAO, 2020). Whiteleg shrimp are tolerant of a wide range of salinities (Gao et al., 2016;Ray and Lotz, 2017;Pinheiro et al., 2020;Chu and Brown, 2021) and stocking densities (Otoshi et al., 2007;Krummenauer et al., 2011;Araneda et al., 2020) (90 to 600 shrimp/m 2 ) making them strong candidates for marine aquaponics. Further, shrimp might alleviate the "economic drain" of fish raised in freshwater aquaponic systems (Quagrainie et al., 2018). ...
Integrated aquaponic food production systems are capable of producing more food on less land using less water than conventional food systems, and marine systems offer the potential of conserving freshwater resources. However, there have been few evaluations of species combinations or operational parameters in marine aquaponics. The goal of this experiment was evaluation of stocking density ratio of Pacific whiteleg shrimp (Litopenaeus vannamei) to three edible halophytes (Atriplex hortensis, Salsola komarovii, and Plantago coronopus) with two C/N ratios in a 3 × 2 factorial design. There were three stocking density ratios (shrimp: plant), 2:1, 3:1, and 5:1; and two C/N ratios, 12 and 15. The results indicated that stocking density ratio exerted a significant impact on shrimp growth. Shrimp reared in 2:1 and 3:1 treatments had better growth performance. In contrast, plants were affected by both stocking density ratio and C/N ratio. Halophytes grown in stocking density ratios of 3:1 and 5:1 with a C/N ratio of 15 had better growth performance and nutrient content. The concentrations of TAN and NO 2 − were below 0.2 mg/ L throughout the experiment, including the higher stocking density ratio treatments. In conclusion, the stocking density ratio of 3:1 with a C/N ratio of 15 was suggested as the optimal condition for the operation of marine aquaponics in which whiteleg shrimp and the three halophytes are target crops.
... L. vannamei is one of the most cultivated species worldwide and the most commonly cultivated marine organism in China [4,5] with numerous advantages such as rapid growth, short maturation period, low nutritional requirements and strong adaptability to the environment. However, for the continued expansion of the aquaculture scale [6], improvements in intensive aquaculture are needed [7]. However, the rapid deterioration of aquaculture environments [8][9][10] and frequently occurring aquaculture diseases [11][12][13] are important factors in restricting and hindering the development of the aquaculture industry [14]. ...
Intestinal bacteria are crucial for the healthy aquaculture of Litopenaeus vannamei, and the coastal areas of China are important areas for concentrated L. vannamei cultivation. In this study, we evaluated different compositions and structures, key roles, and functional potentials of the intestinal bacterial community of L. vannamei shrimp collected in 12 Chinese coastal cities and investigated the correlation between the intestinal bacteria and functional potentials. The dominant bacteria in the shrimp intestines included Proteobacteria, Bacteroidetes, Tenericutes, Firmicutes, and Actinobacteria, and the main potential functions were metabolism, genetic information processing, and environmental information processing. Although the composition and structure of the intestinal bacterial community, potential pathogenic bacteria, and spoilage organisms varied from region to region, the functional potentials were homeostatic and significantly (p < 0.05) correlated with intestinal bacteria (at the family level) to different degrees. The correlation between intestinal bacteria and functional potentials further suggested that L. vannamei had sufficient functional redundancy to maintain its own health. These findings help us understand differences among the intestinal bacterial communities of L. vannamei cultivated in different regions and provide a basis for the disease management and healthy aquaculture of L. vannamei.
... Stress conditions increase energy demand required for aquatic animals (Devreker et al., 2009). In fact, the isosmotic point for lots of marine animals such as L. vannamei and the clam Pinctada margaritifera are repotted to nearly be 20 ‰ (Andrew et al., 2017) and24 ‰ (Shakhmatova et al., 2006). Salinities approaching the isosmotic point, marine animals don't have to expend lots of energy hypoosmoregulating or hyperosmoregulating to maintain their haemolymph osmolality. ...
We examined the growth performance, immune parameters and the susceptibility to Vibrio parahaemolyticus in the clam Cyclina sinensis, which had been reared at different salinity levels of 10‰, 20‰ and 30‰ for 60 days. At the end of the feeding experiment, the biggest shell length and body weight was found in 20‰, followed by 30‰ and 10‰. No significant differences in superoxide dismutase (SOD) activity were observed among the clams held in 10‰, 20‰ and 30‰. Na+/K+ -ATPase (NKA) activity of the clams held in 20‰ and 30‰ were significantly lower than that in group 10‰. The lowest activities of lysozyme (LZM) and glutamic-pyruvic transaminase (GPT) were found in group 10‰. The Integrated Biomarker Response index (IBR) values of the clams had an inverse relationship with salinity: 11.28, 3.40 and 2.85 in 10‰, 20‰ and 30‰, respectively. At the end of the feeding experiment, the clams were infected with V. parahaemolyticus. As time after infection goes on, the survival rate of clams reared in 20‰ was not significantly different with the other two treatments from 24 to 48h after infection. However, from 72 to 120h after infection, it was significantly lower than those reared in 10‰, while it was significantly higher than those reared in 30‰. It is concluded that the clam C. sinensis reared in 10‰ seawater may reduce growth performance and immune ability, whereas increase resistance against V. parahaemolyticus infection.
... In these cases, shrimp is usually raised at salinities between 0.5 and 5 g L −1 , i.e. oligohaline waters from several natural sources, such as well, river, lakes and dams (Nunes and López, 2001;Boyd et al., 2009;Valenzuela-Madrigal et al., 2017). The choice for low salinity is not necessarily a predilection, but actually is most likely related to the cost of artificial sea salts or imported seawater, which could be a substantial expense at inland facilities and therefore systems should be operated at the lowest salinity possible to optimize financial returns (Ray and Lotz, 2017). On the other hand, low salinity may negatively affect physiological processes, such as those related to osmoregulation and exoskeleton development (Li et al., 2017), reducing the productivity. ...
Litopenaeus vannamei production in oligohaline waters (0.5–5 g L⁻¹) is a potential alternative for the continuous expansion of shrimp farming. However, ionic imbalance may affect physiological processes and productivity. In this work, natural seawater inoculation was used as strategy for correction of ionic composition in a biofloc-dominated oligohaline system and its effects on the water quality and nursery performance were evaluated. A 27-day trial was conducted using an experimental biofloc-dominated oligohaline water, salt formulation was based on the mean concentrations of the major ions present in natural oligohaline waters found in Northeastern Brazil. The trial was composed of four treatments of natural seawater inoculation (3, 6, 10 and 13%) and a control, without inoculation (0%); all with four replicates. Post-larvae (PL) of 22 days (0.057 ± 0.002 g) were stocked at 1000 PL m⁻³ in 20,150 L indoor circular tanks. Shrimp were fed 40% crude protein commercial diets twice a day at rations adjusted weekly. Water temperature, oxygen saturation, pH, total ammonia nitrogen, nitrite, nitrate, phosphate, alkalinity, hardness, salinity, conductivity, total suspended solids and settleable solids were monitored. Concentrations of the major ions were measured at the Days 0, 14 and 27. Shrimp sampling was performed weekly and the final zootechnical performance was evaluated by final weight, survival, specific growth rate (SGR), weekly growth rate (WGR), yield and food conversion ratio. Salinity, conductivity and hardness significantly increased according to the increase of seawater inoculation, whereas the other parameters did not differ; all of them were within the range recommended for shrimp culture at low salinity, except nitrate for 0%. Concentrations of Cl⁻, Na⁺, Mg²⁺ and K⁺ and Na⁺:K⁺ ratio significantly increased according to the increase of seawater inoculation. Final weight, survival, SGR, WGR and yield were significantly lower in the 0%, but no differences were found among the treatments (from 3% to 13%). The results found in this work indicate that a seawater inoculation at 3% was an efficient strategy to mitigate negative effects of the ionic imbalance on growth performance of PL reared in biofloc-dominated oligohaline systems.
... Salinity, a key environmental factor that influences the reproduction, growth, development, and survival of aquatic animals, is a major topic in aquaculture and stress biology studies Li et al., 2018;Ponce-Palafox et al., 2019;Ray and Lotz, 2017). Aquatic products cultivated under different salinities exhibit significant differences in flesh quality and texture, and previous studies have indicated that products cultivated in high salinity environments are of the highest quality (Haliloğlu et al., 2004;Hurtado et al., 2006;Xu et al., 2010). ...
Litopenaeus vannamei has a salinity tolerance range of 0.5–78 ppt. In China, cultivation of L. vannamei in high salinity waters in the Circum-Bohai Region resulted in low survival rates and yields because high salinity has toxic effects on shrimp. Thus, identifying differential gene expression in different tissues of L. vannamei under high salinity stress would help revealing its salt tolerance mechanisms. In the present study, L. vannamei was cultivated under two salinity levels (34 and 58 ppt) for 90 days. Gill, muscle, and hepatopancreatic tissues were then extracted from the shrimp for transcriptome sequencing and quantitative real-time PCR, to analyze the differential expression of genes at the transcriptome level. The 1659 significantly differentially expressed genes comprised 436, 318, and 364 upregulated genes and 428, 317, and 156 downregulated genes in gill, hepatopancreatic, and muscle tissues, respectively. Higher differential expression was found in genes related to osmoregulation, ion transport, and antioxidation in gill tissue; immune defense, bacterial lysis, and apoptosis in hepatopancreatic tissue; and development and nutrient metabolism in muscle tissue. The results of this study can enrich the basic knowledge of shrimp stress biology, and provide reference for understanding the molecular mechanism of shrimp salt tolerance.
... There are abundant literature reports on the benefits of biofloc on shrimp post-larvae and juveniles cultured in waters with salinities above 27 g L -1 Emerenciano et al., 2013a;Schveitzer et al., 2013;Khatoon et al., 2016). However, the few studies with BFT in fresh or brackish water (0-18 g L -1 ) have shown conflicting results regarding the growth and survival of cultured shrimp under these conditions (Ray et al., 2011;Maicá et al., 2014;Moreno-Arias et al., 2016;Ray & Lotz, 2017). On the other hand, recent studies indicate that white shrimp cultured in biofloc increases its growth with increased salinity, where the best response was obtained at 25.5 g L -1 (Ponce-Palafox et al., 2019). ...
Silicon dioxide has been used in aquaculture to increase the abundance of diatoms; however, its relationship with water quality or productive performance has not been investigated. Our study evaluated the effect of diatomite on water quality, growth performance and proximate composition of Penaeus vannamei reared in seawater (E1) and brackish water (E2) with biofloc. Two independent experiments (E1 and E2), each one with three treatments with biofloc were evaluated: treatments D with a weekly addition of diatomite (10 g m-3); the treatments D plus a continuous inoculum of diatom Chaetoceros muelleri (DD); and only biofloc like control, for E1 was used post-larvae with an initial body weight (IBW) of 0.0075 g; while in E2 was used juvenile with an IBW of 1.42 g. After seven weeks in E1, non-significant differences were registered in survival, weight gain (WG), specific growth rate (SGR) and feeding conversion rate (FCR) between DD treatment and control. However, in E2, the treatment D showed significantly higher WG (9.83 g) and SGR (4.25% d-1) compared to control (7.64 g and 3.86% d-1 , respectively). Conversely, the FCR was lower in treatment D (1.16) compared to control (1.49). Non-significant differences were recorded in the proximate composition for shrimp, periphyton, and biofloc, among treatments in both experiments. Levels of nitrogenous wastes were similar among treatments. While in E2, the concentration of settleable solids was significantly higher in treatments with diatomite compared to control. Our results recommend the use of diatomite to improve the growth performance of shrimps cultured in brackish water with biofloc.
... Tertiary responses are changes that lead to a drop in productive performance and decreased disease resistance (Chang et al. 2016;Downie and Kieffer 2016). In this sense, water salinity can influence the activity of enzymes (Ahmmed et al. 2017;Tran-Ngoc et al. 2016) and alter locomotor activity and food intake, with direct consequences on animal growth (Nguyen et al. 2014;Ray and Lotz 2017;Montory et al. 2018). Salinity also has a direct influence on hematological and biochemical variables (Breves et al. 2010a), which provides important information regarding the clinical status and energy of fish. ...
Golden pompano (Trachinotus ovatus) is a commercially important marine fish and is widely cultured in the coastal area of South China. Salinity is one of the most important environmental factors influencing the growth and survival of fish. The aims of this study are to investigate the growth, physiological, and molecular responses of juvenile golden pompano reared at different salinities. Juveniles reared at 15 and 25‰ salinity grew significantly faster than those reared at the other salinities. According to the final body weights, weight gain rate, and feed conversion ratio, the suitable culture salinity range was 15–25‰ salinity. The levels of branchial NKA activity showed a typical “U-shaped” pattern with the lowest level at 15‰ salinity, which suggested a lower energy expenditure on osmoregulation at this level of salinity. The results of this study showed that the alanine aminotransferase, aspartate aminotransferase, and cortisol of juveniles at 5‰ were higher than those of other salinity groups. Our results showed that glucose-6-phosphate dehydrogenase significantly increased at 5‰ and 35‰ salinity. Our study showed that osmolality had significant differences in each salinity group. GH, GHR1, and GHR2 had a wide range of tissue expression including the liver, intestine, kidneys, muscle, gills and brain. The expression levels of GH, GHR1 and GHR2 in the intestine, kidneys, and muscle at 15‰ salinity were significantly higher than those in other three salinity groups. Based on the growth parameters and physiological and molecular responses, the results of the present study indicated that the optimal salinity for rearing golden pompano was 21.36‰ salinity.
... After 53 days of rearing, the integration of shrimp with mullet did not influence shrimp production parameters (Table 4), which were similar to results published by other authors (Schveitzer et al., 2013;Ray and Lotz, 2017;Rodrigues et al., 2018;Poli et al., 2019). ...
We evaluated an integrated system for rearing Pacific white shrimp (Litopenaeus vannamei) and white mullet (Mugil curema) in an experimental-scale biofloc system. Performance of the animals, water quality, phosphorus and nitrogen retention and mass balance, and fish hematology and immunology were compared among two treatments: 1) shrimp with mullet integrated system (Shrimp + Mullet), and ii) shrimp without mullet system (Shrimp). A tank with 800 L of useful volume was used to rear the shrimp with a density of 250 shrimp m⁻³. Another tank with 90 L of useful volume was maintained for rearing fish (15 mullet tank⁻¹) in the Shrimp + Mullet treatment. The shrimp treatment also used the 90-L tanks, but without the fish. Water was recirculated into the mullet tanks via a submerged pump and returned by gravity to the shrimp tanks. The shrimp were fed four times a day. A feeding table was used to adjust the amount of feed provided, and the fish were fed only once daily with a ratio of 1% initial biomass to stimulate biofloc consumption (BFT). After 53 days, shrimp growth (final weight 12.56 ± 0.22 g) and survival (91.8% ± 2.9%) were similar between treatments. Fish had adequate survival (91.1% ± 10.2%), and adequate growth for Mugil species (0.71 ± 0.05 g week⁻¹) in the integrated system. In the Shrimp + Mullet treatment, animal productivity was increased by 11.9% by combining Shrimp + Mullet biomass, when compared to the Shrimp treatment. The Shrimp + Mullet treatment also demonstrated a 16.8% increase in phosphorus retention compared to the Shrimp treatment. The hemato-immunological parameters showed that fish kept in a biofloc system had adequate values comparable to those reported for Mugil species. Thus, these experimental-scale results demonstrate that the integration of shrimp and mullet in biofloc systems increases yield and phosphorous retention without compromising fish health and shrimp growth. In addition, we recommend reproducing this integrated system over a longer period and at commercial-scale, supporting an economic analysis.
... Por outro lado, a produtividade neste estudo foi satisfatória em baixa salinidade (4 g/L), sugerindo a viabilidade da criação desta espécie nesta condição. Este mesmo fato foi comprovado por Ray & Lotz (2017) que verificaram a viabilidade do cultivo de L. vannamei em baixa salinidade. ...
O crescimento da aquicultura e a crescente demanda por alimentos de origem animal, aliado às novas exigências dos consumidores, vêm fazendo com que aumente a preocupação destes com a contaminação ao ambiente devido à execução da atividade, o que motiva técnicos e pesquisadores a buscarem novas alternativas mais sustentáveis para a produção animal. Assim, esta revisão foi realizada com o objetivo de debater os principais aspectos em relação à carcinicultura e à tecnologia de bioflocos (BFT) empregada neste sistema. Pesquisas estão sendo desenvolvidas na área, visando aprimorar as técnicas e estabelecer novas metodologias, e apresentam resultados satisfatórios em todas as fases do ciclo de produção. Este trabalho apresenta resultados obtidos pelo uso do sistema BFT, tanto para as características de desempenho, como para as características de qualidade da água e saúde relacionadas à carcinicultura.
... vannamei) is the most common species reared in biofloc-based systems (Lara et al., 2017. Ray andRay, 2017). The choice of the most appropriate additional carbohydrate supplementation method is critical to the culture process. ...
Biofloc technology involves manipulation of the C/N ratio to convert toxic nitrogenous wastes into useful microbial protein and helps improve the water quality in a closed system. Poly-β-hydroxybutyric (PHB) has been demonstrated to have positive effects on aquatic animals in an aquaculture system. A 40-day lab scale trial was carried out to investigate the potential of PHB as an additional carbohydrate for a shrimp Litopenaeus vannamei bioflocs nursery in brackish water. Three methods of carbohydrate supplementation were investigated. The first method was the addition of glucose daily at a percentage of 75% of the feed (GLU-group). The second method was the addition of PHB plus glucose; when the total ammonia nitrogen (TAN) level above 2 mg L ⁻¹ was observed, glucose was added, 6 g C to 1 g TAN (PHB + GLU-group). The third method was the addition of PHB only (PHB-group). During the 40-d trial, most of the ratios of dissolved organic carbon to total ammonium nitrogen (DOC/TAN) were maintained at 20 in the three groups. The average concentration of TAN in the PHB + GLU-group (0.23 ± 0.19 mg L ⁻¹ ) was significantly lower than those of the GLU-group (0.28 ± 0.26 mg L ⁻¹ ) and the PHB-group (0.30 ± 0.33 mg L ⁻¹ ) (P <.05). The average concentration of nitrite nitrogen in the PHB-group (0.16 ± 0.24) was significantly lower than those of the GLU-group and the PHB-group (P <.05). The concentrations of TAN and nitrite nitrogen from the PHB + GLU-group were more stable than those from the PHB-group and GLU-group. Nitrate nitrogen accumulated, as expected, in the three groups, and no significant differences were observed (P >.05). The survival rate and final weight in the PHB + GLU group were significantly higher than those of the other groups (P <.05). The food conversion ratio of the PHB group (1.52 ± 0.23) was significantly lower than those of the other groups. Taken together, our results showed that PHB is a favorable and convenient additional carbohydrate for shrimp Litopenaeus vannamei biofloc nurseries in brackish water. PHB + GLU was the best carbohydrate supplementation method.
... Biofloc systems have been used with great success for shrimp (Brito et al., 2014(Brito et al., , 2016Marinho et al., 2017;Ray & Lotz, 2017) and tilapia cultivated in freshwater (Ekasari et al., 2015;Long et al., 2015;Pérez-Fuentes et al., 2016;Alves et al., 2017;Miranda-Baeza et al., 2017;Zapata-Lovera et al., 2017). Tilapia can adapt to a biofloc system because of their resistance to high solids levels and filter-feeding ability, thus allowing the absorption of the suspended flocs (Avnimelech, 2011), although more information on tilapia performance in brackish water is needed. ...
A 42-day trial was conducted to evaluate the effects of a low-salinity biofloc system with different stocking densities on water quality and zootechnical performance of Nile tilapia fingerlings (10 g/L). Four treatments were tested at different densities: 500 fish/m³, 750 fish/m³, 1,000 fish/m³ and 1,250 fish/m³, all in triplicate. Fingerlings of Oreochromis niloticus (initial mean weight of 1.17 ± 0.05 g) were stocked in twelve experimental black-plastic tanks (40 L) with no water exchange during the experimental period. Molasses was added daily to the system at 30% of the amount of feed, and fish were given four daily rations of a formulated feed composed of 36% crude protein and 9% lipids. Water quality variables (dissolved oxygen, pH, salinity, TAN, NO2, NO3 and PO43) did not demonstrate significant differences between the treatments. However, significant influences (α ≤ 0.05) of the stocking densities were observed for total suspended solids, settleable solids, final weight, yield, and protein efficiency ratio. The results showed survival over 96%, final weight values between 12 and 18 g, yield between 9.49 and 15.27 kg/m3, water consumption of 52 to 101 L/kg fish, and total time of settling chambers between 238 and 305 h/kg fish. These results indicate a negative effect of stocking density on final weight, survival, alkalinity, NO2, PO43 and water consumption, and a positive effect on yield in Nile tilapia fingerling culture (1-20 g) in a low-salinity biofloc system with densities up to 1000 fish/m³.
... Zhou and Boyd (2016) stated that the use of the ammonia ion selective electrode is strongly affected by sodium and potassium, thus the electrodes are not recommended for waters with high salinity. However, researchers still use and rely on TAN measurements using an ion selective probe in seawater (Morris, Samocha, Davis, & Fox, 2011;Ray & Lotz, 2017). Differences in the present study could be due to probe failure or improper calibration, analytical error, human error, contamination, etc. ...
Increasing feeding rates may provide an increase in production, thus nutrients such as nitrogen, phosphorus and organic matter will also increase. These nutrients promote a greater oxygen demand and concentrations of toxic metabolites which can lead to frequent problems with low dissolved oxygen and an abundance of blue-green algae. Four feed management practices were evaluated among sixteen 0.1 ha ponds culturing Pacific white shrimp (Litopenaeus vannamei). Feeding treatments included hand feeding using the Standard Feeding Protocol (SFP), SFP plus 15% from 8 to 16 weeks, an automatic-solar timer which fed SFP+15%, and an AQ1 acoustic demand feeder allowing up to 12 kg/day·pond based on shrimps feeding response. Samples were analysed at weeks 0, 4 and 8–16 for the following parameters: chlorophyll a, total ammonia nitrogen, nitrite–nitrogen, nitrate–nitrogen, total nitrogen, total phosphorus, soluble reactive phosphorus, total suspended solids, total suspended volatile solids, turbidity, conductivity, salinity and biological oxygen demand. Samples were collected and shipped overnight to Auburn, Alabama for off-site analysis. On-site water quality was also obtained at the farm. The AQ1 acoustic demand feeder produced the most shrimp with a yield of 4,568 kg/ha; however, the AQ1 also had the highest total ammonia nitrogen and nitrite–nitrogen levels late in the growing season. The AQ1 feeder may be a viable, reduced labour and cost alternative for the shrimp commercial industry; however, such technologies must also be matched to the ability of the production system to process nutrients.
... In the present study, utilization of nonconventional carbon source de-oiled oil palm kernel meal had shown a significant effect on the growth performance and feed utilization of L. vannamei. The increase in growth performance and feed utilization of the shrimps reared in biofloc were reported by several researchers (Kuhn et al., 2010;Megahed., 2010;Emerenciano et al., 2011;Krummenauer et al., 2011;Ray et al., 2011;Emerenciano et al., 2012;Xu and Pan, 2012;Kim et al., 2014;Ray and Lotz, 2017). In addition to this, biofloc acts as a supplemental feed source which results in the better zootechnical performance (Burford et al., 2004;Kuhn et al., 2008;Megahed, 2010). ...
A 40-day experiment was conducted to study the effect of de-oiled oil palm kernel meal based biofloc system on growth performance and digestive enzyme activity of Litopenaeus vannamei. Juveniles of L. vannameiwith an average weight of (0.82±0.02 g) were stockedin tanks with a water volume of 150 L at a stocking density of 300 PL m-3. Highest weight gain percentage (519.05±9.52), protein efficiency ratio (1.78±0.02) and survival rate (88.67±0.88) were observedin oil palmkernel meal based biofloc treatment. Lowest FCR value (1.61±0.02) has been recordedin biofloc treatment. Although the digestive enzymes had not shown any significant difference, a slightincrease in the protease and amylase activities have been observedin biofloc treatment. So the present study suggeststhat non-conventional carbon source–de-oiled oil palm kernel meal can be utilizedfor the development of biofloc.
This study investigated the bacterial composition and inferring function profiles in the biofloc system rearing Litopenaeus vannamei postlarvae (PL) at a low salinity condition. PL (~ stage 15) were stocked in four parallel tanks filled in water with a salinity of 5.0‰ at a density of 4000 individuals per m3 for a 28-days culture experiment, during which glucose was added as a carbon source with a C:N of 20:1. At the end of the experiment, water was sampled from each tank and pooled to extract microbial DNA for high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. Results showed that the bacterial community at 28 d was dominated by phyla of Proteobacteria (45.8%), Bacteroidetes (21.1%), Planctomycetes (13.5%), Chlamydiae (10.3%), and Firmicutes (6.8%). A proportion of 81% inferring KEGG functions of this bacterial community is associated with metabolism. Among functions relating to nitrogen metabolism, 48.5% were involved in converting ammonia to glutamate. Still, the proportion of those engaged in transformation among ammonia, nitrite, and nitrate was 18.0%, inferring higher protein-synthesis but lower inorganic nitrogen-transformation capacities of the bacterial community. At the same time (28 d), high levels of total nitrogen (231.3±6.0 mg L-1) and biofloc (127.0±63.0 mL L-1) but low concentrations of ammonia (0.04±0.01 mg L-1), nitrite (0.2±0.1 mg L-1) and nitrate (12.9±2.5 mg L-1) were observed. The results supply a novel insight for understanding bacterial community function in the biofloc system nursing L. vannamei PL at low salinity.
In order to increase shrimp production and minimize detrimental environmental impacts of aquaculture, the maintenance and regulation of the growth and composition of phytoplankton communities and nutritional balance are critical. Silicon (Si) is an essential nutrient for diatoms and other types of microorganisms, but the information about the Si impact on their growth is extremely scarce. Monosilicic and polysilicic acids were tested in several shrimp cultivation systems in Jiangsu Province, China. In pond waters, the concentrations of monosilicic and polysilicic acids sharply reduced by 36–95% and 35–75%, accordingly, as compared with those in supply water sources. The microbial cell abundance was strongly dependent on monosilicic acid, while the correlation with polysilicic acid was absent. In laboratory experiments, monosilicic acid added to pond water or probiotic solution at 1 and 2 mM Si had a significant positive effect on cell abundance. Over three days, the concentrations of monosilicic acid decreased by 81 to 91% in pond water and by 11 to 24% in probiotic solution. In probiotic solutions, the degree of polymerization of silicic acid was more intensive than that in shrimp pond waters. The data obtained demonstrates the importance of systematic studies related to the functions of Si in shrimp aquaculture.
The world population continues to increase day by day. Therefore, aquaculture needs to grow in order to response the need for protein foods and to cope with the problem of scarcity. However, this enlargement should require taking place in a sustainable way in order to protect the environment and natural resources. The rapid development in the production of seafood as a food sector brought several issues that are necessary to be studied. Particularly, the most important limitations of conventional aquaculture are feed and feeding regimes, high volumes of water requirement, and its pollution potential to natural water resources. Biofloc technology (BFT) is a sustainable aquaculture method for pollution prevention that is based on the principle of reuse of nitrogen-based pollutants which are considered organic waste in aquaculture. In this review, the studies in the literature that considered the parameters affecting BFT are examined. BFT holds a promising response to the global concern of making aquaculture more sustainable. Considering the water quality, fish growth, and immunological positive effects, it is foreseen that BFT systems will be important in aquaculture in the future. Currently, operational parameters are mainly adjusted on a trial-and-error way, and there is a clear need to shift towards a more scientific-based approach to be able to commercialize this technique.
A vital goal of cleaner production involves developing agricultural production systems capable of ensuring sufficient yields of highly necessary foods to meet the increasing needs of the global population while minimizing the associated economic and ecological costs. Integrated agri-aquaculture systems (IAAS) offer a number of advantages for sustainable agriculture, including water reutilization, discharge mitigation, and increased profitability by leveraging the symbiotic relationship between organic waste, bacterial mineralization, and plant filtration. The aim of this study was to assess the production of two food items of global socio-economic importance cultivated at different salinities: Pacific white shrimp (Penaeus vannamei) and tomatoes (Solanum lycopersicum L.) grafted to salinity tolerant wild tomatoes. Pacific white shrimp were cultured at a density of 125 organisms/m³ and tomatoes at a density of 3 plants/m. The shrimp growth test consisted of three salinity levels: 2, 4, and 6 g/L. The corresponding tomato salinity treatments were conducted using shrimp water effluents; Steiner’s universal nutrient solution (SNS) was used for the control treatment. The experimental period lasted 175 days. The highest tomato production (77.46 t/ha) was attained with SNS, with no significant difference from the salinity of 2 g/L. Shrimp final mean weight, survival, and production were higher at the 6 g/L salinity; and all the other zootechnical parameters decreased with lower salinity. When compared with the hydroponic system using a cost-benefit analysis (CBA), the production costs associated with the IAAS were lower primarily because of the reduced (or null) costs of fertilizer, and irrigation water. When grafted plants were used, the salinity tolerance of the commercial hybrid increased and shrimp could be cultured at appropriate salinity to facilitate osmoregulation. Chemical fertilization requirements were reduced and acceptable yields were obtained for the tomato crop by grafting to salinity-tolerant rootstocks.
Los probióticos han surgido como alternativas prometedoras para mejorar la resistencia a las
enfermedades y estimular el crecimiento del camarón cultivado. El objetivo del presente trabajo
fue evaluar el efecto de la adición de probióticos en la supervivencia del camarón e indicadores
productivos a través de un metaanálisis. Se realizaron búsquedas en las bases de datos de PubMed,
SciELO y Google académico en todos los idiomas desde 1980 hasta 2017. Solo se seleccionaron
los experimentos con camarones peneidos aparentemente sanos, y cuyos resultados se publicaron
en revistas arbitradas con cualquier medida de dispersión. La supervivencia, la velocidad de
crecimiento específico (VCE) y el factor de conversión alimenticia (FCA) se seleccionaron como
resultados. Se recopiló información sobre el diseño experimental, las especies de camarones, la
etapa de desarrollo, el tipo de cepa probiótica, modos de administración, entre otros. Se incluyeron
un total de 100, 60 y 49 estudios para evaluar los efectos probióticos en la supervivencia, VCE y
FCA, respectivamente. Los probióticos aumentaron la supervivencia en comparación con los
controles (DME = 3,068; IC del 95%: 2,594 a 3,543) y mejoró la VCE (DME = 3,811, IC del 95%:
3,269 a 4,354) y el FCA (DME = -3,194, IC del 95%: -3,469 a -2,920) en el modelo de efectos
aleatorios mediante diferencia en medias estandarizada (DME), considerando la fuente de
heterogeneidad y los sesgos de publicación (es decir, cuando la decisión de publicar o no depende
del resultado del experimento, por ejemplo, no arrojar resultados negativos). La supervivencia, la
VCE y el FCA mejoraron en los camarones tratados con probióticos. Este metaanálisis muestra
que tanto la calidad de los datos como el enfoque utilizado fueron relevantes, lo que permitió
diseñar una guía para optimizar el uso de probióticos en la cría de camarones.
Palabras clave: camarón; metaanálisis; factor de conversión alimenticia; supervivencia
Aquaculture is increasingly being intensified, and the resulting higher stocking densities and feed inputs in closed systems can consequently lead to water quality fluctuations and/or deteriorations. Some of the most relevant water quality parameters in closed aquaculture systems include dissolved oxygen/redox potential, pH, salinity, temperature, and nitrogenous waste. These parameters should not deviate to extreme levels in order to minimize non-infectious diseases and subsequently ensure higher productivity in aquatic animals. Some husbandry strategies and novel systems to prevent or ameliorate deviations in these parameters will be discussed along with physiological responses in aquatic animals due to water quality induced non-infectious diseases. A final section will discuss the implications to noxious algae as a consequence of water quality deteriorations as well as feed spoilage/contamination along with mitigating strategies to ensure a better product for human consumers.
Minimizing ammonium is one of the most important concerns in the practice of aquaculture. Chemoautotrophic bacterial nitrification (CBN) and heterotrophic bacterial assimilation (HBA) are the two main ammonium pathways in aquaculture water under light-limited conditions. CBN oxidizes ammonia–nitrogen (NH4⁺-N) to nitrite–nitrogen (NO2⁻-N) and finally to nitrate–nitrogen (NO3⁻-N), and this is the primary strategy employed in recirculating aquaculture systems using fixed-cell bioreactors. Zero-exchange management systems based on HBA and biofloc technology have been developed referred as biofloc aquaculture systems. HBA is encouraged in biofloc aquaculture systems by increasing the C/N ratio. However, NO3⁻-N build-up was found in many studies examining these systems, with CBN proposed as the responsible mechanism and documenting the factors leading to the occurrence of the CBN process. This paper examines the relative importance of CBN and HBA in biofloc aquaculture systems. A mechanism is proposed and future study aimed at mediating NH4⁺-N pathways in biofloc aquaculture systems is recommended.
Ammonia is one of the most harmful risks for success of fish and shrimp culture. There is no effective solution for harmlessness of ammonia in traditional aquaculture operations except exchanging water, which would bring negative effects on environment, or fixing expensive equipment. Biofloc technology (BFT) that appeared in recent years supplies a novel solution for this issue without exchanging huge water and fixing equipment. This technology could assimilate ammonia almost in real time with many other supplemental benefits. Because of the very high nutritional value for fish and shrimp, bioflocs, the by-product of BFT, could also be reused as a complemented food in situ or a gradient for feedstuff to replace expensive fishmeal or be processed to pellet diet to feed fish and shrimp directly. However , some aspects with regard to the effective use of biofloc as a food source for fish and shrimp, such as high lipid content, productivity, and palatability, need to be further researched in detail.
The total ammonia nitrogen (TAN) removal efficiency and bacterial community composition of bioflocs with <50-μm particle size, > 50-μm particle size and un-sieved bioflocs were investigated in the current study. The initial ratio of dissolved organic carbon to TAN (DOC/TAN) in the three groups were about 14:1. No significant difference was found in the removal rate of TAN, average concentrations of TAN and nitrite nitrogen among the three groups (P > 0.05). The C/N (w/w) ratio of the > 50-μm bioflocs was significantly higher than those of the other groups. No significant differences were found in the crude protein content in the bioflocs among the three groups. The development of the bacterial community compositions of the bioflocs was analyzed by Illumina MiSeq sequencing analyses. Most OTUs were shared among the three groups at all the sampled time points. With the increase in the relative abundance of phylum Firmicutes, that of phylum Proteobacteria, Chorolexi, and Bacteroidetes decreased in all the three groups. The phylum Firmicutes and genus Bacillus were predominant in all the sampled time points. At the end of the experiment, genus Bacillus accounted for 81% in the < 50-μm group, 82% in the > 50-μm group, and 75% in the un-sieved group.
Superintensive shrimp culture in zero-exchange, biofloc-dominated production systems is more biosecure and sustainable than traditional shrimp farming practices. However, successful application of this technology depends upon optimizing dietary formulations, controlling Vibrio outbreaks, and managing accumulative changes in water quality and composition. A 49-d study investigated the effect of two commercial feeds of differing protein content and an indoor limited-exchange, biofloc-dominated culture environment on Litopenaeus vannamei performance and tissue composition, water quality and ionic composition, and Vibrio dynamics. Juveniles (5.3g) were stocked at 457/m3 into four 40m3 shallow raceways containing biofloc-dominated water and fed one of two commercial feeds with differing protein content, 35 or 40%. Shrimp performance, Vibrio populations, and changes in shrimp and culture water composition were monitored. There were no significant differences (P>0.05) in shrimp performance (survival, weight, growth, specific growth rate, total biomass, yield, feed conversion ratio, and protein efficiency ratio) or proximate composition between feed types. The 40% protein feed resulted in higher culture water nitrate and phosphate concentrations, alkalinity consumption and bicarbonate use, and higher phytoplankton density. The presence of Vibrio, specifically Vibrio parahaemolyticus, reduced shrimp survival. This survival decrease corresponded with increased culture water Vibrio concentrations. Culture water K+ and Mg2+ increased significantly (P<0.05), and Sr2+, Br-, and Cl- decreased significantly (P<0.05) over time. While Cu2+ and Zn2+ did increase in shrimp tissue, no heavy metals accumulated to problematic levels in culture water or shrimp tissue. These results demonstrate the importance of monitoring Vibrio populations and ionic composition in limited-exchange shrimp culture systems.
Bioflocs Oxygen dynamics Resuspension, mixing, and sludge management Nitrogenous waste products Temperature Feeds and feeding Economics Sustainability Outlook and research needs Acknowledgment References
Super-intensive shrimp culture has been studied extensively in the last decade. We presently define super-intensive shrimp BFT systems as ones that hold above 300 shrimp/m3 (often up to 900) and yield typically 3-6 kg/m3, though higher yields are reported.
With these high biomass and feeding, the organic load is above the holding capacity of the system. Thus, a careful monitoring is needed and a fraction of the suspended matter has to be drained out.
Super-intensive production is still expensive, significantly above global market price of shrimp, yet may bring a profit if fresh non-frozen shrimp are sold to near-by lucrative market.
The coastal water pH varies with salinity. Therefore, to study the effect of salinity induced pH variations on benthic foraminifera, live specimens of Rosalina globularis were subjected to different salinities (10, 15, 20, 25, 30, 35 and 40 0/00) with pH varying from 7.2 to 8.2. A total of 210 specimens were used and the experiment was conducted in replicates. It was observed that the salinity induced pH changes affect the calcification of foraminifera. However the response is not linear. The maximum growth is reported in the specimens kept at 35 0/00 salinity (pH 8.0) while the rest of the specimens maintained at salinity higher or lower than 35 0/00, showed comparatively lesser growth. A significant drop in pH severely hampers the calcification capability of benthic foraminifera. Specimens kept at 10 and 15 0/00 (pH 7.2 and 7.5, respectively) became opaque within two days of lowering the salinity and later on their tests dissolved within 24 and 43 days, respectively. Besides calcification capability, pH also affects reproduction. No specimen reproduced at 10 and 15 0/00 salinity while only a few specimens (3 %) reproduced at 20 0/00. As compared to 10-20 0/00 salinity, ∼60 % reproduction was observed in specimens subjected to 25-40 0/00 salinity. The drop in pH also decreased the calcification rate as specimens at 20 0/00 salinity took twice the time to reach maturity than normal range (25-40 0/00). We conclude that salinity induced drop in pH adversely affects the calcification capability and reproduction in benthic foraminifera. It is inferred that the time required to reach reproductive maturity increases at the extreme salinity tolerance limits. However, beyond a certain limit, a further increase in pH does not affect benthic foraminifera; rather they respond to salinity as per their salinity tolerance range.
This study aimed to evaluate the effect of low salinity on the water quality, microbial flocs composition and performance of Litopenaeus vannamei juveniles reared over 40 days in a zero-water-exchange super-intensive system at 0, 2, 4 and 25 g L−1. At 0 g L−1, the mortality was total at the 26th day, and consequently, these salinity data were not included in the statistical analysis. Among the water quality parameters, only pH and the total suspended solids concentration were significantly influenced by salinity. However, a trend towards intensification of the nitrification processes was observed as the salinity increased, with the lowest ammonia and the highest nitrite and nitrate concentrations found at 25 g L−1. The concentrations of ciliates and flagellates diminished and increased, respectively, with the increase in salinity. Diatoms predominated at 25 g L−1, whereas at 2 and 4 g L−1, chlorophytes were more abundant. Microbial floc crude protein content was reduced with the increase in salinity, whereas ash content demonstrated the inverse trend. The best overall growth performance and survival were observed at 25 g L−1. However, satisfactory productivity was also found at 4 g L−1, suggesting the viability of rearing L. vannamei at low salinity under zero-water-exchange conditions.
Algal species vary considerably in sensitivity to the commonly used herbicide atrazine, and it is hypothesized that several factors may contribute to species-specific sensitivity. In this study four estuarine microalgal species, a planktonic chlorophyte (Dunaliella tertiolecta), a benthic chlorophyte (Ankistrodesmus sp.), a cryptophyte (Storeatula major) and a dinoflagellate (Amphidinium operculatum), were exposed to atrazine to determine toxi-city and identify factors that might influence species sensitivity. Atrazine effects were examined at the population (cell density, primary productivity and biomass), cellular (biovolume), and subcellular (pigment composition, protein concentration and lipid concentration) levels. Atrazine significantly decreased cell density, productiv-ity rate, biomass and biovolume in all the algal populations tested at atrazine concentrations ≥12.5 µg l −1 . Toxicity values (96 h EC 50 values) for the four species ranged from 11.87 to 146.71 µg l −1 . Species sensitivity rankings varied with endpoint measured. Overall, Ankistrodesmus sp. was the most sensitive species followed by Storeatula, Dunaliella and Amphidinium. Cellular biovolume was a significantly more sensitive test endpoint for Amphidinium, chlorophyll a was a significantly more sensitive test endpoint for Ankistrodesmus sp., and phototrophic carbon assimilation was a significantly more sensitive test endpoint for both Storeatula and Am-phidinium. Algal subcellular responses to atrazine were also species dependent. Chlorophyll a concentration per cell decreased in the green algae, increased in Amphidinium and did not change in Storeatula. Total lipids per cell increased in Storeatula, decreased in Amphidinium and did not change in the green algae. Ankistrodesmus sp. pigments were not significantly altered after atrazine exposure; however selected Amphidinium pigments increased per cell, and selected Dunaliella and Storeatula pigments decreased per cell in the atrazine treatments. Atrazine significantly reduced cellular biovolume in all test species. Species with smaller biovolumes and less chlorophyll a per cell tended to be more sensitive to atrazine exposure based on population growth rate.
Inland aquaculture of shrimp in low salinity waters is widespread in many regions worldwide. Owing to its ability to grow and survive in low salinity environments the Pacific white shrimp, (Litopenaeus vannamei Boone) has become the candidate of choice for low salinity culture. Remediation techniques have been developed to improve the osmoregulatory capacity of shrimp reared in low salinity waters. These techniques have evaluated water modification strategies that improve low salinity waters used for production by adding potassium and magnesium fertilizers and dietary approaches that involve modification of the feeds offered to shrimp with supplements that might improve osmoregulatory capacity. Based on our own experience as well as what we found predominantly in the literature, it appears that modification of the rearing medium with potassium and magnesium fertilizers is more effective than dietary modification techniques at improving the growth, survival and osmoregulatory capacity of shrimp reared in low salinity waters.
A new high-resolution spectrofluorimetric probe and an automatic water-quality monitoring station (AWQMS) have been used to
record seasonal variations in the spatial distribution of three functional groups of phytoplankton in a Mediterranean water-supply
reservoir. In comparison with classical methods, the combined use of these innovative techniques enables development of faster
and less laborious spatial distribution surveys, thus favouring higher-frequency and spatially more detailed measurements,
and, consequently, a better understanding of phytoplankton dynamics. The results show that the observed variations can be
explained by the interaction between the buoyancy properties of the phytoplankton and the mixing characteristics of the reservoir.
During the winter, when the lake was isothermal and the phytoplankton was dominated by diatoms, there was no significant spatial
variation. In the spring, when the phytoplankton was dominated by chlorophytes there was also very little variation but some
motile species formed patches when the wind speed was low. The most pronounced non-uniform distributions of phytoplankton
were observed during the summer when the phytoplankton community was dominated by positively buoyant cyanobacteria. Then there
was a very strong link between the vertical and horizontal gradients which were also related to the prevailing meteorological
conditions.
Zero water exchange, super-intensive culture of shrimp in enclosed raceway type systems can be considered environmentally friendly in that containment of water within the system prevents potential spread of disease between the wild populations and cultured animals and avoids nutrient rich waste from polluting coastal waters. However, as a relatively new strategy for shrimp production, there is much still to be learned about the potential biological and economic benefits of producing shrimp in suspended microbial floc based systems. Understanding shrimp feeding behavior and quantification of shrimp feed consumption provides valuable information for culturists to improve feed management, one of the keys to economic viability. The objective of this study was to evaluate the nutritional contribution of varying levels of microalgae/bacterial floc on survival, growth, food consumption, and FCR of Litopenaeus vannamei juveniles fed diets with different protein levels in replicated experimental microcosm tanks. The 20 day experiment evaluated 9 treatments, three water types fed three different protein diets. Water was recirculated within a sump and consisted of either clear, UV filtered water, water containing microbial floc from an adjacent zero exchange super-intensive raceway production unit, or a 50:50 mix of clear water and raceway water. Diet treatments were either no food, 25% or 35% protein content. Treatments were randomly assigned to 50 L, mesh covered plastic bins receiving each water type. Each treatment consisted of five replicates, each containing 44 shrimp, with a mean stocking weight of 1.82 ± 0.71 g for a final density of 300 per m2. Shrimp in each treatment (except the no feed treatment) were fed 3 times daily via a specially designed feed tray. Food consumption and FCR were calculated based on weight gain, survival, total consumed feed, feed loss through leaching, and initial feed moisture content. Results were analyzed by two-way analysis of variance (ANOVA) and differences between the means analyzed by Tukey's test (α = 0.05). Survival in the fed treatments was greater than 98% in all treatments (P > 0.05). Survival in the non-fed treatments was significantly higher in the raceway water treatments than in the clear water treatment (P < 0.05). Final weight, weight gain, final biomass, food consumption and FCR were significantly higher (P < 0.05) in all treatments fed with 35% protein feed. This result suggests a positive relationship between the growth parameters and the protein content of the feeds in this system, and confirms the benefit of natural productivity for production of L. vannamei.
In light of the increasing demand for fish, the challenge for planners now is to accelerate aquaculture development and to plan for new production, making urban areas not only centres of marketing and distribution, but also of production, particularly using urban wastewater. This book includes papers from authors in the USA, Europe and Asia that review these developing issues from the perspective of both developed and developing countries. Urban aquaculture education is also considered. The book is intended for those researching in aquaculture, water resources, urban planning and geography. It has 19 chapters and a subject index.
Aquaculture is an increasingly diverse industry with an ever-growing number of species cultured and production systems available to professionals. A basic understanding of production systems is vital to the successful practice of aquaculture. Published with the World Aquaculture Society, Aquaculture Production Systems captures the huge diversity of production systems used in the production of shellfish and finfish in one concise volume that allows the reader to better understand how aquaculture depends upon and interacts with its environment. The systems examined range from low input methods to super-intensive systems. Divided into five sections that each focus on a distinct family of systems, Aquaculture Production Systems serves as an excellent text to those just being introduced to aquaculture as well as being a valuable reference to well-established professionals seeking information on production methods.
Suspended organic particles produced in an intensive shrimp pond with an earthen substratum can significantly enhance shrimp growth. However, the role of the substratum in eliciting this effect is unknown. It was hypothesized that clay particles, derived from the substratum, are important in transferring suspended organic particles to the pond bottom where they become available to shrimp. To test this hypothesis, it was determined if suspended particles, produced in a plastic-lined pond without an earthen substratum, can improve shrimp growth. Juvenile Penaeus vannamei were reared in 120-liter microcosm tanks at a density of 40 shrimp/m2. A 2 × 2 factorial experiment was conducted in which triplicate tanks received flow-through water from either a 337-m2, plastic-lined pond used for intensive shrimp culture or from a seawater well. In addition, shrimp were fed either a commercial diet ad libitum or were unfed. After 14 days, there was a highly significant water source effect on shrimp growth (P < 0.001). Growth rates of shrimp in pond water + feed (1.20 g/wk) were 62% greater than growth rates of shrimp in well water + feed (0.74 g/wk). Unfed shrimp in pond water grew 0.23 g/wk, whereas unfed shrimp in well water lost weight (−0.045 g/wk). These results indicate that algal-clay flocculation is not an important mechanism in eliciting the growth-enhancing effect of shrimp pond water and that particles suspended in pond water may not need to interact with the substratum in order to contribute to shrimp growth.
The microbial community in minimal‐exchange, superintensive culture systems should be managed to cycle nutrients and enhance production. This paper explores the effects of biofloc concentration reduction and a fish‐free diet on several microbial community characteristics. In 16, 3.5‐m diameter, 71‐cm deep outdoor tanks, shrimp were stocked at 460/m3. Eight of the tanks received a fish‐free, plant‐based feed and eight received a conventional feed containing fishmeal and fish oil. Within each diet type, biofloc concentration was reduced in four of the tanks and was not reduced in the other four tanks. Photosynthetically active radiation (PAR) extinction coefficients, photosynthetic oxygen production, chlorophyll‐a (chl‐a) concentrations, pheophytin‐a (pheo‐a) concentrations, and the sum of odd and branched chain fatty acid concentrations as a bacterial abundance indicator (BAI) were measured. Biofloc reduction significantly (P≤ 0.003) decreased PAR extinction coefficients, chl‐a concentration, pheo‐a concentration, and BAI concentration, while significantly increasing photosynthetic oxygen production. Diet did not significantly affect (P > 0.05) any of these measured parameters. The observed changes in microbial community characteristics corresponded with, and may help to explain, significantly improved shrimp feed conversion ratios, growth rate, final weight, and biomass yield in the tanks with biofloc reduction.
Many introductory statistics textbooks in education, psychology, and the social sciences consider the Friedman test to be a nonparametric counterpart of repeated-measures ANOVA, just as the Kruskal-Wallis test is a counterpart of oneway ANOVA. However, it is known in theoretical statistics that the Friedman test is a generalization of the sign test and possesses the modest statistical power of the sign test for normal as well as many nonnormal distributions. Although not familiar to researchers, another significance test that can be regarded as a nonparametric counterpart of repeated-measures ANOVA is a rank-transformation procedure, in which the usual parametric statistical analysis is performed on ranks replacing the original scores. In the present computer simulation study we compared the ordinary paired-samples Student t test, the Wilcoxon signed-ranks test, and the sign test for correlated samples from normal, uniform, mixed-normal, exponential, Laplace, and Cauchy distributions, for which the relative efficiency of the methods is known. We also compared repeated-measures ANOVA, repeated-measures ANOVA on ranks, and the Friedman test for k mutually correlated samples from the same distributions, where k = 2,3, and 4. Power functions revealed that the Friedman test performed like the sign test for all distributions, whereas ANOVA on ranks performed like the Wilcoxon test These comparisons emphasize that classification of these statistical tests in introductory textbooks should be revised and that more attention should be paid to the rank transformation concept.
Chronic toxicity of nitrate (NO3−) has not been well documented in the culture of penaeid shrimp. To interpret this problem, lab-scale research was conducted in recirculating aquaculture systems (RAS) to determine the long-term impacts of nitrate on shrimp growth, survival, total mass of shrimp per system (shrimp biomass), antennae length, and tissue pathology. The first experiment, Trial (A), was performed over a six week period at 11 (ppt) salinity and consisted of a Control A (35ppm nitrate-N), Treatment A1 (220ppm nitrate-N), Treatment A2 (435ppm nitrate-N), and Treatment A3 (910ppm nitrate-N). No differences were observed between control A and treatment A1 in terms of shrimp survival, growth, shrimp biomass, and antennae length. Treatment A2 exhibited no significant differences compared to Control A in terms of survival and growth, but did exhibit significant negative impacts (P
This study was conducted to determine the individual and combined effects of ammonia and nitrite on Litopenaeus vannamei postlarvae (25- to 45-d old PL) at 10 ppt salinity, 28 C, and a pH of 7.8. The independent variables were salinity, total ammonia nitrogen (TAN), and nitrite nitrogen (NO2-N). The TAN experiments were conducted at 18 and 10 ppt salinity, and the NO2-N test was conducted at 10 ppt salinity. Combined TAN and NO2 tests were also conducted at 10 ppt salinity. The 48-h lethal concentration (LC50) values for TAN at 18 ppt salinity, TAN at 10 ppt salinity, and NO2-N at 10 ppt were observed to be 42.92, 39.72 (2.26 and 2.09 mg/L unionized ammonia-N), and 153.75 mg/L, respectively. When NO2-N was adjusted to the lowest observed effect concentration (LOEC) level and TAN concentrations were varied, synergistic effects were observed, with a 48-h LC50 calculated to be 28.2 mg/L TAN (1.49 mg/L unionized ammonia-N). However, when the ammonia level was adjusted to the LOEC and nitrite was varied, antagonistic effects were observed with a 48-h LC50 calculated to be 163.3 mg/L NO2-N. This study demonstrated that the combined toxic effects of ammonia and nitrite need to be considered when developing standard operating procedures for shrimp culture.
1.1. The hemolymph is isosmotic to seawater at 745 mOs/kg in P. aztecus, 768 mOs/kg in P. duorarum, 680 mOs/kg in P. setiferus, 699 mOs/kg in P. stylirostris, and 718 mOs/kg in P. vannamei.2.2. The hemolymph is hyperosmotic to seawater at salinities below the isosmotic concentrations and hypoosmotic to those above.3.3. With respect to sodium and chloride, the hemolymph is hyperionic to seawater at low salinities and hypoionic to seawater at high salinities.4.4. P. aztecus and P. duorarum are weaker osmotic and ionic regulators at low salinities than P. setiferus, P. stylirostris, and P. vannamei.5.5. There are no significant differences in the osmotic and ionic regulatory capabilities of all five species at high salinities.
A 4×4 factorial experiment was conducted to determine the effects of salinity (0.2‰, 11‰, 21‰, and 31‰) and temperature (20°C, 24°C, 28°C, and 32°C) on survival, growth, and energy budget of juvenile Litopenaeus vannamei with the initial wet body weight of 0.274–0.283 g. The experiment lasted for 5 wk. The results showed that all shrimp survived at 11‰, 21‰, and 31‰, irrespective of temperature; at 0.2‰, survival decreased with increasing temperature from 20°C to 28°C, then plateaued at 32°C. At all levels of temperature with increases of salinity within the range tested, specific growth rate or food consumption gradually increased, reaching the maximum value and thereafter declined. At 0.2‰, specific growth rate, food consumption, or apparent digestibility coefficient exhibited an increasing trend from 22°C, reaching the maximum value at 28°C, then showed a decline up to 32°C with increasing temperature, whereas at salinities of 11‰, 21‰, and 31‰; specific growth rate, food consumption, or apparent digestibility coefficient exhibited an increasing trend. By contrast, feed efficiency generally decreased in response to increasing temperature within the salinity range tested.
Recent efforts have been made to culture marine shrimp in systems operating under low or zero-water exchange and with decreased water salinity. The aim of this study was to investigate the impact of various salinity levels on qualitative and quantitative characteristics of the natural community and, more particularly, ciliated protozoa, and compare this information with shrimp growth and survival. Tanks with 9‰ salinity were characterized by a higher pH, but also by a significantly higher concentration of chlorophyll a (Chl a) per weight of suspended matter (1.93 ± 0.72 µg Chl a/mg TSS) than tanks with 18‰ (1.29 ± 0.68 µg Chl a/mg TSS) or 36‰ (1.37 ± 0.61 µg Chl a/mg TSS) salinity. Concentrations of ciliates (max 6000 cells mL−1) showed considerable fluctuations over the sampling period, reflecting the impact of water salinity, dynamic interactions between ciliates and their diverse roles within the shrimp production system. There was no significant difference between survival rates of shrimp reared at 9‰, 18‰ or 36‰, but decreasing salinity from 36‰ to 9‰ led to a significant decrease in final shrimp body weight (from 13.40 ± 0.26 g to 10.23 ± 2.72 g). Future work should address the potential of ciliates as an indicator of aquaculture water quality, as is currently being done in the wastewater industry, and the contribution of ciliates as food sources.
Penaeus vannamei juveniles (initial mean weight=1.6 g) were cultured at salinities of 5, 15, 25, 35, and 49 ppt for 35 days. Highest mean final weights and greater than 2g/week growth were obtained in the lowest salinities tested, 5 and 15 ppt. Mean final weights at 5 and 15 ppt were not significantly different, but were significantly greater than at the higher salinities tested. Mean final weights at 25 and 35 ppt were not significantly different, but were significantly greater than at 49 ppt. Mean final weights by treatment were: 12.4 g (5 ppt), 12.2 g (15 ppt), 10.8 g (25 ppt), 11.1 g (35 ppt), and 9.8 g (49 ppt). Survival was not significantly different among salinity treatments. A second population of juveniles (initial mean weight=2.2 g), infected with IHHN virus (infectious hypodermal and hematopoietic necrosis virus), was compared concurrently at 25 and 49 ppt. The growth pattern was similar, with significantly higher mean final weights at 25 ppt than at 49 ppt. Additionally, a significant interaction between population and salinity level (two-way ANOVA, P=0.035) indicated that the IHHN-positive population had relatively lower growth at the high salinity level. Mean final weights in the second population were 10.3 g (25 ppt) and 8.5 g (49 ppt). As in the population not infected with IHHN, survival was not significantly different among treatments.
High-intensity, zero-exchange shrimp ponds contain a high density of flocculated particles, rich in bacteria and phytoplankton, compared with flow-through systems. The flocculated particles provide a potential food source for shrimp. Short-term tank experiments were conducted to determine the retention of nitrogen (N) from natural biota, dominated by flocculated particles, in white shrimp (Litopenaeus vannamei) at a high-intensity, zero-exchange shrimp farm in Central America (Belize Aquaculture (BAL)). There were two treatments: ‘floc’ and ‘floc+20%’ (3×1000-l replicate tanks each) based on two densities of flocculated particles. The floc density in the ‘floc’ treatment was typical of shrimp growout ponds at BAL, whereas the ‘floc+20%’ treatment had a 20% higher density of flocculated particles. Three consecutive experiments were conducted with 1, 5 and 9 g shrimp, respectively. At the start of the experiment, 15N-ammonium was added to the tanks and assimilated by the natural biota. Shrimp were maintained in these tanks for 48 h after the 15N-nitrogen enrichment. After this time, shrimp were found to be enriched with 15N-nitrogen. It was calculated that between 1% and 3% of the particulate nitrogen in the tanks, principally from the flocculated particles, was retained by the shrimp. The proportion of estimated daily nitrogen retention of the shrimp contributed by the natural biota was calculated to be 18% to 29% for 1 to 9 g animals in the floc treatment. There was a tendency for greater retention in the floc+20% treatments, but this trend was not consistent. This study suggests that natural biota, which in this system was largely flocculated particles, can contribute substantially to the nutrition of L. vannamei. There are, therefore, benefits for shrimp in the promotion of flocculated particles in L. vannamei ponds. Whether this translates into improvements in shrimp growth and production efficiency remains to be established.
Inland shrimp culture is being practiced in several regions of the United States. In Alabama, the culture of shrimp (Litopenaeus vannamei) in inland low salinity well water (approximately 4.0 ppt) faces several challenges. The ionic composition of these waters is deficient in several key minerals, including potassium (K+) and magnesium (Mg2+). The objective of the present study was to evaluate the effects of several aqueous K+ and Mg2+ concentrations on survival, growth, and respiration in juvenile L. vannamei. Two experiments, a 14-day trial with postlarvae and a 7-week trial with juvenile (∼ 0.2 g) shrimp were conducted to evaluate effects of K+ supplementation to culture water. Four different levels of K+ (5, 10, 20, and 40 mg l− 1) were utilized and a treatment of 4 ppt reconstituted seawater was used as a reference for comparison to ideal ionic ratios. Additionally, a 6-week growth trial (∼ 1 g juvenile shrimp) was performed to evaluate the effects of five concentrations of Mg2+ (10, 20, 40, 80, 160 mg l− 1). Following completion of growth trials, measurements of basal respirometry rates were conducted to assess stress. Results from the 7-week K+ growth trial indicated significant differences (P < 0.05) in survival and growth among treatments. Individual weight, specific growth rate, and percent weight gain appeared to increase with increasing K+ concentration (decreasing Na:K ratios). Results from the Mg2+ experiment reveal a significant difference in survival between the lowest Mg2+ treatment (60%) and all other experimental treatments (90–97%). However, no differences in growth were observed. Shrimp respiration in the lowest Mg2+ treatment (10 mg l− 1) was significantly higher than in the 80 mg l− 1 treatment. These results suggest a potentially higher energetic cost associated with depressed aqueous Mg2+ concentrations that are common in low salinity environments.
The inland farming of penaeid shrimp in low-salinity waters is now de facto in many regions of the world, yet there is little information pertaining to the suitability of waters with various ionic compositions for shrimp culture. In the present study, short-term (48 h) survival of Pacific white shrimp, Litopenaeus vannamei postlarvae (PL), and long-term (4 weeks) growth and survival of juvenile L. vannamei in various inland saline ground waters were evaluated. A correlation between survival and growth of PLs and the ionic composition of the waters was performed. Short-term bioassays were conducted on 10-, 15- and 20-day-old postlarvae using waters from various wells. Salinity was decreased at a rate of 4 ppt h−1 using fresh water from 24 ppt until a salinity of 2 ppt above the target salinity was reached. Water in the containers was then slowly exchanged with water from inland saline wells. Survival of the PLs was evaluated 48 h after the start of acclimation. In the second study, four replicates of 15 juveniles were placed in 144-l square tanks containing various saline well waters from west Alabama. Growth and survival were evaluated after 4 weeks. The ionic makeup of the various inland well waters from Alabama, Florida, Mississippi and Texas was analyzed to characterize each source. Survival of PL10 shrimp in some of the waters was similar to survival in the low-salinity reconstituted seawater control and was significantly different from the control in other waters. Survival of PL15 was greater than survival of PL10 but similar to PL20. Some waters were unsuitable for shrimp culture at all PL stages tested. Survival and growth of the juveniles paralleled results of the short-term bioassays. Shrimp survived and grew well in waters in which more than 90% of the postlarvae acclimated and survived in. Juvenile survival and growth were intermediate and low in waters in which PL acclimation was intermediate and low, respectively. Survival appears to be positively correlated with ions such as K, Mg and SO4 and negatively correlated with a high concentration of iron.
The expansion of the aquaculture production is restricted due to the pressure it causes on the environment by the discharge of waste products in the water bodies and by its dependence on fish oil and fishmeal. Aquaculture using bio-flocs technology (BFT) offers a solution to both problems. It combines the removal of nutrients from the water with the production of microbial biomass, which can in situ be used by the culture species as additional food source. Understanding the basics of bio-flocculation is essential for optimal practice. Cells in the flocs can profit from advective flow and as a result, exhibit faster substrate uptake than the planktonic cells. The latter mechanisms appear to be valid for low to moderate mixing intensities as those occurring in most aquaculture systems (0.1–10 W m− 3). Yet, other factors such as dissolved oxygen concentration, choice of organic carbon source and organic loading rate also influence the floc growth. These are all strongly interrelated. It is generally assumed that both ionic binding in accordance with the DLVO theory and Velcro-like molecular binding by means of cellular produced extracellular extensions are playing a role in the aggregation process. Other aggregation factors, such as changing the cell surface charge by extracellular polymers or quorum sensing are also at hand. Physicochemical measurements such as the level of protein, poly-β-hydroxybutyrate and fatty acids can be used to characterize microbial flocs. Molecular methods such as FISH, (real-time) PCR and DGGE allow detecting specific species, evaluating the maturity and stability of the cooperative microbial community and quantifying specific functional genes. Finally, from the practical point of view for aquaculture, it is of interest to have microbial bio-flocs that have a high added value and thus are rich in nutrients. In this respect, the strategy to have a predominance of bacteria which can easily be digested by the aquaculture animals or which contain energy rich storage products such as the poly-β-hydroxybutyrate, appears to be of particular interest.
Nitrite in environmental water samples is reduced at room temperature to nitric oxide in acidic medium containing vanadium (III). Nitrate is also rapidly reduced after heating to 80-90 degrees C. Nitric oxide is removed from the reaction solution by scrubbing with helium carrier gas and is detected by means of a chemiluminescence NOx analyzer. Nanogram detection limits are obtained. The method has the advantage of not requiring highly acidic solutions for nitrate reduction and has been applied to the analysis of a variety of environmental waters, sediment, plant materials, and human urine and blood serum.
American Water Works Association, and Water Pollution Control Association Standard Methods for the Examination of Water and Wastewater
APHA (American Public Health Association), American Water Works Association, and
Water Pollution Control Association, 2005. Standard Methods for the Examination of
Water and Wastewater, 21st ed. (Washington, D.C., USA).
ESS Method 340.2: Total Suspended Solids Volatile Suspended Solids (Ignited at 550 °C) In: Environmental Sciences Section
ESS, 1993. ESS Method 340.2: Total Suspended Solids, Mass Balance (Dried at 103-105
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Biofloc production systems for aquaculture
- Hargreaves