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Effects of background colour on growth performance, skin pigmentation, physiological condition and innate immune responses of goldfish, Carassius auratus
Abstract
A study was carried out to investigate the effects
of background colour on the growth perfor-
mance, skin colour, haematology, physiological
condition and non-specific immune responses of
goldfish, Carassius auratus. Goldfish were reared
in tanks with four different background colours
(white, black, blue and red) for 8 weeks. Fish
growth performance markedly rose in white
background compared with the other treatments.
There was no significant difference in haemato-
logical parameters or plasma proteins concentra-
tions between treatments. Plasma cortisol of fish
reared in red background was significantly
higher than that in black and white back-
grounds. Plasma antiprotease and lysozyme activ-
ities were more than doubled in white and black
treatments compared with the red and blue
groups. The other immune parameters tested
(plasma peroxidase, complement and bactericidal
activities) did not significantly change between
treatments. Skin carotenoid content and the
intensity of fish skin colour extremely diminished
in white background. This study revealed that
red and blue backgrounds are chronically stress-
ful and immunosuppressive in goldfish. White
backgrounds will preferably be used for the cul-
ture of goldfish for best fish growth. However, a
way to revert the colour loss of goldfish skin
reared in white backgrounds remains to be
investigated.
... The effects of different background colours on fish vision and behaviour can give one of the most promising approaches for maintaining body colour in fish (Asra Nor Izaty and Norazmi-Lokman, 2019). Fish physiology and behaviour may be influenced by keeping them in artificial environments that are considerably different from their native habitats (Eslamloo et al., 2013). The present study is carried out on filament barb, Dawkinsia filamentosa to evaluate the influence of different tank background colour on growth, survival, and body colour pigmentation and also the stress and non-specific immune parameters of filament barb. ...
... In another study on koi carp was observed that green colour tank has significantly improved the growth and survival than other tank colour (Bairwa et al., 2021). The study on goldfish confirmed that the white tanks were highly preferred and white coloured tank had the highest growth compared to black coloured tanks (Eslamloo et al., 2013) and these findings are contrary to the present study for filament barb, which clearly indicates that its highly species specific and the tank background colour differentially affects the species feeding pattern. All the above studies suggest that fish colour preferences are speciesspecific, depending on their natural environments, behaviour, and feeding patterns. ...
... This is due to the availability of suitable ecosystem to develop the desired pigmentation in their body. In the study conducted on goldfish, it was observed that black colour tank has improved the body pigmentation and carotenoid content (Eslamloo et al., 2013) and in case of filament barb also the body colouration and carotenoid level was found higher for fish reared in black colour tank. Eslamloo et al. (2013) study suggest that the goldfish reared in white tank led to body discolouration and the same effect was observed with filament barb. ...
The various environmental factors have a significant impact on cultured species. One such factor influencing larval production in finfish hatcheries is the tank colour. The current study appraised at how different background tank colours such as white, red, blue, green, and black influenced the growth, survival, and body pigmentation of filament barb, Dawkinsia filamentosa. The experiment was conducted for 30 days and the fish were fed with powdered diet thrice a day containing 30% crude protein and 4% crude lipid at satiation level. At the end of study, it was found that the final body length in the black colour tank (15.33 ± 0.17 mm) was significantly (p < 0.05) higher compared to other tank colour groups. In comparison to other treatments, the final body weight (65.17 ± 1.48 mg) and average daily weight gain (1.56 ± 0.05 mg day⁻¹) in the black colour tank was found to be significantly (p < 0.05) higher, while the white colour tank (35.83 ± 1.64 mg; 0.59 ± 0.06 mg day⁻¹) were significantly (p < 0.05) lower. The fish reared in the black colour tank had significantly (p < 0.05) higher specific growth rate (4.22 ± 0.07% day⁻¹) and thermal growth coefficient (19.4 ± 0.6), whereas the white colour tank had the lowest (SGR = 2.24 ± 0.17% day⁻¹; TGC = 7.27 ± 0.71). The survival rate was significantly (p < 0.05) higher in black colour tank (78.33 ± 1.67%) and lowest survival was observed in white tank colour (56.67 ± 3.33%), which represented an improvement of almost 20% for the fishes reared in black colour tank. Fish reared in black tank had the significantly higher level of carotenoid content (2.33 ± 0.08 μg g⁻¹) and fish reared in white tank had lower body carotenoid level (1.02 ± 0.05 μg g⁻¹). It was observed that the different tank colour did not (p > 0.05) cause any change in the stress and non-specific immune parameters of filament barb. Based on the findings, it can be stated that black background colour is the best tank colour for rearing and production of filament barb.
... Similar to our study, results on blood biochemical parameters were reported by Bayrami et al. (2017) in young sterlet (Acipenser ruthenus), Ninwichian et al. (2018) in snakeskin gourami (Trichogaster pectoralis) and Ghavidel et al. (2020) fingerling grouper, Epinephelus coioides. In contrast, the results of some studies by Eslamloo et al. (2015) and Rahnama et al. (2015) in goldfish and rainbow trout showed blood biochemical parameters did not change among different background colours. It seems that different results in these studies may be due to different species, feeding period, life stage and background colour used. ...
... As a bioindicator in choosing the optimal background colour, measuring the level of stress-related parameters such as cortisol can be a useful method (Eslamloo et al., 2015). The elevated cortisol levels in our results indicate the stress that fish experience when raised in inappropriate coloured tanks. ...
... In the present study, the cortisol level in juveniles of red-coloured tank was very low (p < 0.05). This is not in line with the results of other researchers such as Bayrami et al. (2017) in young sterlet; Eslamloo et al. (2015) in goldfish and Wang et al. (2017) in Siberian taimen larva (Hucho taimen), which recorded high mortality due to elevated cortisol level. However, the results from Ninwichian et al. (2018) and Ghavidel et al. (2020) in snakeskin gourami and grouper did not show significant differences in serum cortisol levels among treatments. ...
The background colour of the fibreglass tanks attributed to their significant correlation with light intensity and spectrum serves as one of the major factors influencing
growth performance and stress levels of cultured fish. Moreover, it plays a key role in
the successful production of the cultured species, which is challenging under confinement conditions. On the other hand, Asian sea bass (Lates calcarifer) has received significant attention among researchers due to its high-profit value and growing demand
in the global market. Hence, the current study was designed to investigate the effects
of different tank background colours (white, red, black and blue) on growth indices,
body composition, digestive enzymes, haematological parameters, expression of
stress and growth-related factors in L. calcarifer. Therefore, fish (160.90 ± 6.0 g) were
distributed into 12 fibreglass tanks (250-L) including four treatments in triplicates and
were reared for 6 weeks. According to the present results, the highest specific growth
rate was observed in fish raised in red-coloured tank followed by white and black
tanks. Maximum weight gain (WG) and high protein efficiency ratio (PER) were observed in fish raised in red-coloured tank followed by white-, black- and blue-coloured
tanks, respectively. Modulation of the main digestive enzymes was observed across
four treatments indicating different strategies for the utilization of nutrients by fish.
Fish from red- and white-coloured tanks showed a lower level of cortisol and higher
levels of heat shock protein (HSP70) when compared to the other groups. The present
findings indicate that red colour is the most suitable background colour for rearing
Asian sea bass juveniles followed by white colour compared with the other ones.
... Rearing conditions, such as environment and feeding, which are very different from those of natural habitats, influence fish physiology and behavior (Eslamloo et al., 2015). Especially in intensive farming, fish are exposed to grading, handling, transportation, stocking densities, diseases, vaccination, food withdrawal or aggression, among other, that affect welfare and can lead to acute or chronic stress (Sneddon et al., 2016). ...
... The characteristics of rearing tanks are an important issue to consider in aquaculture, since it has been demonstrated that they can induce stress (Ishibashi et al., 2013), affect growth and survival (Martinez-Cardenas and Purser, 2011;Wang et al., 2017), induce skeletal anomalies (Cobcroft and Battaglene, 2009), and alter fish behavior (Höglund et al., 2002;Cobcroft and Battaglene, 2009) and skin pigmentation (van der Salm et al., 2005;Eslamloo et al., 2015). Despite all the evidence, tank characteristics are often under-considered in aquaculture, and, for instance, the color of the rearing tanks is seldom described in the scientific literature. ...
... In tilapia, Oreochromis mossambicus, white and grey backgrounds induce skin lightening, whereas a black background induces skin darkening and a more stressful response (van der Salm et al., 2005). In goldfish, red and blue backgrounds are chronically stressful, whereas a white background improves fish growth, but generates a skin color loss (Eslamloo et al., 2015). In Lophiosilurus alexandri dark colored tanks promoted an increase in plasma cortisol levels and a reduction in brightness of the skin, while the use of light colors resulted in paler skin (Costa et al., 2017). ...
Skin pigmentation pattern is a species-specific characteristic that depends on the number and the spatial combination of several types of chromatophores. This feature can change during life, for example in the metamorphosis or reproductive cycle, or as a response to biotic and/or abiotic environmental cues (nutrition, UV incidence, surrounding luminosity, and social interactions). Fish skin pigmentation is one of the most important quality criteria dictating the market value of both aquaculture and ornamental species because it serves as an external signal to infer its welfare and the culture conditions used. For that reason, several studies have been conducted aiming to understand the mechanisms underlying fish pigmentation as well as the influence exerted by rearing conditions. In this context, the present review focuses on the current knowledge on endocrine regulation of fish pigmentation as well as on the aquaculture conditions affecting skin coloration. Available information on Iberoamerican fish species cultured is presented.
... These characteristics endow fish with the ability to differentiate colors and environmental details (Escobar-Camacho et al., 2017). Many fish species use this ability to perform various tasks, such as capturing food (Eslamloo et al., 2015). The tanks used in the RAS can be manufactured in any color, although most of the commercialized tanks have blue, green and black colors (McLean, 2020).Therefore, the color of the environment can influence the contrast between food and the background inside the tank, and thus influence its capture and consumption and, consequently, the growth of fish (Banan et al., 2011;Eslamloo et al., 2015;Ninwichian et al., 2018). ...
... Many fish species use this ability to perform various tasks, such as capturing food (Eslamloo et al., 2015). The tanks used in the RAS can be manufactured in any color, although most of the commercialized tanks have blue, green and black colors (McLean, 2020).Therefore, the color of the environment can influence the contrast between food and the background inside the tank, and thus influence its capture and consumption and, consequently, the growth of fish (Banan et al., 2011;Eslamloo et al., 2015;Ninwichian et al., 2018). The color of the environment can also cause stress and behavioral changes, with subsequent effects on blood cortisol levels, which can also directly impact the metabolism and growth of animals (McLean, 2020). ...
... The color of the environment can also cause stress and behavioral changes, with subsequent effects on blood cortisol levels, which can also directly impact the metabolism and growth of animals (McLean, 2020). The color of the environment can also affect skin pigmentation (Eslamloo et al., 2015;Ninwichian et al., 2018;Pavlidis et al., 2008), due to the action of melanin concentrating hormone (MCH) and alpha-melanocyte stimulating hormone (α-MSH) (Takahashi and Kawauchi, 2006). In addition to control over skin pigmentation, α-MSH is also related to the production of cortisol and stress in fish (Lamers et al., 1992;Van Der Salm et al., 2005). ...
This study assessed the effects of different tank colors (white, blue, green and black) on the performance, metabolism and skin pigmentation of Colossoma macropomum cultivated in recirculating aquaculture system (RAS). In Phase 1 of the experiment, 224 juvenile C. macropomum (4.04 ± 0.32 g) were cultivated for a period of 30 days at a density of 0.5 juveniles/L. In Phase 2 of the experiment, the juveniles (34.32 ± 12.14 g) were cultivated within each treatment for another 20 days at a density of 0.25 juveniles/L. Biometrics were performed for all juveniles after 30 and 50 days of cultivation. Blood was also collected after 50 days of cultivation and skin pigmentation analysis and determination of the hepatosomatic index (HIS) and lipid concentration in the liver (HL) were performed. Juveniles grown in white tanks had the highest final weight (FW), total length (TL) and weight gain (WG) among treatments at the end of the both phases. At the end of Phase 2, juveniles grown in white tanks had higher levels of triglycerides (p < 0.05) than juveniles of the other treatments. Juveniles grown in black tanks had darker pigmentation and higher hemoglobin and total plasma protein (p < 0.05) than the other treatments. Tank color was found to affect the performance, pigmentation and metabolism of juvenile C. macropomum cultivated in RAS, with white tanks providing the best environment for cultivation and welfare.
... Of less rarified value, the snakeskin gourami is too lightly colored when reared in white tanks, too dark when cultured in black tanks but, in blue tanks, has normal skin color (Ninwichian et al., 2018); color differences that can create a doubling in market value (from~US$10 to~$US22). Cultivation of goldfish (Eslamloo et al., 2013) and false clownfish (Yasir and Qin, 2009) in white tanks likewise results in too light individuals with the consequence of down-grading in price. Selection for élite tank color, therefore, is significant to food fishes but perhaps even more critical for ornamentals when considering overall body color and consumer preference. ...
... White backgrounds enhance circulating cortisol in the sterlet (Bayrami et al., 2017), while Nile tilapia and summer flounder register lowest cortisol response when reared in red tanks (McLean et al., 2008;Fig. 2); although cyprinids express cortisol elevation (Ebrahimi, 2011;Eslamloo et al., 2013; Table 1). White-adapted common carp experience reduced blood cortisol and pH, and elevated pCO 2 (Papoutsoglou et al., 2000), suggesting a lower level of stress accompanied by decreased ventilation rate. ...
... Ezigbo, 2018aEzigbo, , 2018bAdewumi, 2015), Pacific bluefin tuna (Ishibashi et al., 2013;Okada et al., 2015) and Nile tilapia (McLean et al., 2008) mortality rates for other juvenile and adult fish have generally been reported as unaffected by tank coloration. Nonetheless, and while likely stress-related, goldfish exposed to black and white tanks presented higher plasma lysozyme than measured in red and blue tanks (Eslamloo et al., 2013) and, in larval yellow catfish, whole body lysozyme was elevated in fish held in blue tanks when compared against marooncolored tanks (Pichirikkat et al., 2013). Color change in fish is known to be important at cleaning stations, perhaps providing signals to cleaner species (Caves et al., 2018) but also, perhaps, providing contrast between ectoparasites and body, thereby easing parasite detection. ...
Tanks offer significant flexibility for aquaculture production. When in an optimally operated water reuse configuration, they enable farming of most, if not all species of fish, in geographically mismatched regions, with escapees becoming less consequential. Runoff of used water too can be more readily controlled, and wastes and by-products more easily handled and remediated. Tank-based aquaculture, therefore, augments the sector's environmental compatibility. Another potential benefit of tanks is that they can be manufactured in a wide variety of colors. Most commercial facilities, however, employ a limited palette; most often accepting green, blue and black. Many studies though, indicate that certain species perform better, in terms of growth and feed conversion, when maintained in alternative colored tanks. Different tank colors also impact larval survival, animal health, apparent levels of stress and even level of aggression. Body color too is strongly influenced by background color and this has significance to consumers of food species that are sold skin-on whole/gutted, and the value of ornamentals. The present contribution reviews the effects that tank color may have on various physiological control and behavioral processes in larval and post-larval fishes.
... According to our findings, haematocrit and haemoglobin were lower in fish reared in the blue tanks. In Carassius auratus (Eslamloo, Akhavan, Eslamifar, & Henry, 2015), Huso huso (Banan, Kalbassi, Bahmani, & Sadati, 2011) and Acipenser ruthenus (Bayrami, AllafNoverian, & Asadi Sharif, 2016), the tank colour did not affect haematocrit and haemoglobin. The increase in haematocrit and haemoglobin is a strategy to meet the increased demand for oxygen by increasing the oxygen-carrying capacity of blood during the periods of high energy demand (Montero et al., 1999). ...
... In the present study, plasma total protein and albumin were higher in fish reared in the black tanks. Eslamloo et al. (2015) showed that the tank colour had no effect on blood protein and albumin in Carassius auratus. Also, the colour of the tanks did not affect blood protein levels in freshwater catfish, Lophiosilurus alexandri (Costa et al., 2017), and plasma albumin in Huso huso (Banan et al., 2011). ...
... In E. coioides, the plasma cortisol level was not affected by the tank colour, similar to the observations in jundia and juvenile beluga (Banan et al., 2011) whereas the plasma cortisol was affected by the tank colour in goldfish with the highest value of cortisol in fish reared in red tanks (Eslamloo et al., 2015). This controversy could be related to the species-specific responses, different background colours used, duration of the study and experimental conditions (Rotllant et al., 2003 2006). ...
In this study, the effects of different background colours on growth performance and physiological parameters of Epinephelus coioides were investigated. One hundred eighty E. coioides (average weight 18.16 ± 0.07 g) were distributed in black, white and blue 300‐L tanks and fed to satiation for 60 days. The tank colour had no significant effect on the weight gain, condition factor, hepatosomatic index and specific growth rate (p > .05). The lowest amount of viscerosomatic index and the highest carcass protein were recorded in the white tank (p < .05). Daily food intake, feed conversion ratio and plasma glucose were significantly higher in the blue tank (p < .05). The highest levels of haematocrit and plasma triglyceride were observed in the white tank, while the total protein and albumin were higher in the black tank compared to the other tanks. The tank colour had no significant effects on the plasma cortisol level (p > .05). Our findings showed that colours used in this study did not evoke stress and thus had no effect on growth, but some metabolic adaptation occurred in each colour to achieve optimum growth.
... coloration, stress response, neural and hormonal processes, and feed acceptance (Barton 2002;H€ oglund et al. 2002;Strand et al. 2007;Banan et al. 2011;Eslamloo et al. 2015;Rahnama et al. 2015;Zhang et al. 2015). Several studies have indicated that various background colors affect growth in different species: larval Eurasian Perch Perca fluviatilis exhibited the highest growth in light-gray and white tanks (Tamazouzt et al. 2000); juvenile Beluga Huso huso grew better in black tanks (Banan et al. 2011); feed intake and growth efficiency of juvenile Rainbow Trout Oncorhynchus mykiss reared in yellow tanks were significantly higher than those of fish from blue, red, and white tanks (Rahnama et al. 2015); Goldfish Carassius auratus growth performance markedly increased with a white background (Eslamloo et al. 2015); and based on growth performance, light-colored tanks (yellow and white) were optimum for rearing Taimen Hucho taimen larvae (Wang et al. 2016). ...
... coloration, stress response, neural and hormonal processes, and feed acceptance (Barton 2002;H€ oglund et al. 2002;Strand et al. 2007;Banan et al. 2011;Eslamloo et al. 2015;Rahnama et al. 2015;Zhang et al. 2015). Several studies have indicated that various background colors affect growth in different species: larval Eurasian Perch Perca fluviatilis exhibited the highest growth in light-gray and white tanks (Tamazouzt et al. 2000); juvenile Beluga Huso huso grew better in black tanks (Banan et al. 2011); feed intake and growth efficiency of juvenile Rainbow Trout Oncorhynchus mykiss reared in yellow tanks were significantly higher than those of fish from blue, red, and white tanks (Rahnama et al. 2015); Goldfish Carassius auratus growth performance markedly increased with a white background (Eslamloo et al. 2015); and based on growth performance, light-colored tanks (yellow and white) were optimum for rearing Taimen Hucho taimen larvae (Wang et al. 2016). Ullmann et al. (2011) introduced blue as the favorable tank color for juvenile Barramundi Perch. ...
... Moreover, Espinoza et al. (2017) reported a cortisol-mediated pathway responsible for ROS increase in fish; to minimize ROS effects, the production of antioxidant enzymes increases. Some researchers have found that dark-background-adapted fish exhibit higher cortisol levels than those adapted to white tanks (Eslamloo et al. 2015;Rahnama et al. 2015); however, the reverse status, in which dark-backgroundadapted fish grow better, has also been reported (Harder and Summerfelt 1996;Banan et al. 2011;Okada et al. 2015). From the first line of the enzymatic defense mechanism against free radicals, GPX activity increased significantly for Barramundi Perch in black tanks, while the lowest GPX levels were recorded for fish in blue and white tanks. ...
The oxidative status and intestinal and liver histology of Barramundi Perch Lates calcarifer juveniles were investigated in an experiment using different tank colors (black, red, blue, and white) over 6 weeks. It has been previously shown that background color can affect physiological processes in different species. The background colors did not cause significant differences in malondialdehyde, catalase, or glutathione S‐transferase, whereas superoxide dismutase and glutathione peroxidase activities were significantly higher in fish that were kept in black tanks. Plasma cortisol of fish adapted to blue and white tanks was significantly lower than that of fish in black tanks. The liver total antioxidant capacity was highest for fish that were maintained in white and blue tanks. The results of histopathological evaluation revealed that tank colors did not have significant effects on intestinal mucosal and enterocyte dimensions. No specific alterations were found in the liver or intestine of fish relative to the tank background color during the experimental period. In conclusion, white and blue tanks resulted in improved oxidative status of Barramundi Perch juveniles.
... Tank color is an important environmental factor that may significantly influence the performance of cultured fish (McLean et al. 2008). Several studies have revealed that the rearing tank color influences the growth performance, feed utilization, stress responses, behavior, and skin color of fish (Banan et al. 2011;El-Sayed and El-Ghobashy 2011;Eslamloo et al. 2015;Kesbiç et al. 2016). Inappropriate tank colors can induce stress, which can reduce the growth performance and feed utilization efficiency of cultured fish (Strand et al. 2007;Wang et al. 2016Wang et al. , 2017. ...
... Inappropriate tank colors can induce stress, which can reduce the growth performance and feed utilization efficiency of cultured fish (Strand et al. 2007;Wang et al. 2016Wang et al. , 2017. Moreover, fish may rapidly alter their skin color in response to stress or other environmental stimuli such as background color (Eslamloo et al. 2015). Changes in skin color significantly affect consumer acceptance and the market value of fish. ...
... In addition, many studies have reported that tank color does not significantly affect the juvenile growth performance of various fish species, including common carp (Papoutsoglou et al. 2000), beluga (Huso huso) (Banan et al. 2011), and Caspian Kutum (Rutilus frisii kutum) (Imanpoor and Abdollahi 2011). The previous studies and our results suggest that tank color may be an important factor that influences the growth performance and feed utilization in aquaculture, and the degree of this influence depends on the fish species (El-Sayed and El-Ghobashy 2011; Eslamloo et al. 2015;Kesbiç et al. 2016). Moreover, different fish species at different life stages may respond differently to tank color (Papoutsoglou et al. 2005). ...
The effects of tank color on the growth, stress responses, and skin color of snakeskin gourami (Trichogaster pectoralis) were investigated in this study. Fish with initial body weights of 5.03±0.00 g were reared in five experimental tank colors (white, red, green, blue, and black) for 8 weeks. Each tank color was tested in triplicate with an initial stocking density of 15 fish per tank. Fish were fed with commercial sinking pellets at 4% of the average body weight per day. Growth performance, feed utilization efficiency, stress indicators (hematocrit, blood glucose, plasma cortisol levels), and skin color parameters were investigated. The fish reared in blue tanks had a significantly higher average final body weight (9.73 ± 0.14 g) and significantly lower average feed conversion ratio (3.42 ± 0.12) than the fish reared in black tanks (P < 0.05). The fish reared in black tanks exhibited higher average hematocrit (36.63 ± 1.11%), blood glucose (48.33 ± 1.45 mg dL⁻¹), and plasma cortisol (9.00 ± 0.56 μg dL⁻¹) levels than those reared in the other tank colors. However, the blood glucose levels in only the fish reared in black tanks were significantly higher than those in the fish reared in the other tank colors. The fish skin color ranged from very pale (high skin lightness) in the white tanks to very dark (low skin lightness) in the black tanks, and 80% of the variation in skin lightness were explained by the tank lightness. The use of a blue tank resulted in normal skin color; hence, blue tanks will not affect the customer acceptance of the fish. Our study revealed that blue is the most appropriate tank color for culturing snakeskin gourami.
... The colors of the spheres may have influenced the results of this study, although little is known regarding the impact of color on fish rearing performance. Studies have shown that some tank wall colors can improve growth (Tamazouzt et al. 2000;Karakatsouli et al. 2007;Eslamloo et al. 2015). Blue can reduce stress (Volpato and Barreto 2001) and is preferred by Rainbow Trout (Luchiari and Pirhonen 2008). ...
... Blue can reduce stress (Volpato and Barreto 2001) and is preferred by Rainbow Trout (Luchiari and Pirhonen 2008). Eslamloo et al. (2015) observed increased growth in Goldfish Carassius auratus that were reared with a white-walled tank in comparison to those reared with black, blue, and red walls. Eslamloo et al. (2015) also reported increased stress with red and blue tank walls. ...
... Eslamloo et al. (2015) observed increased growth in Goldfish Carassius auratus that were reared with a white-walled tank in comparison to those reared with black, blue, and red walls. Eslamloo et al. (2015) also reported increased stress with red and blue tank walls. Gilthead Seabream Sparus auratus showed a preference for blue substrate (Batzina et al. 2014). ...
This study evaluated the effectiveness of two different environmental enrichment structures on the growth and condition of juvenile Rainbow Trout Oncorhynchus mykiss. Trout were reared in covered tanks with either vertically suspended linear or spherical structures. Spherical structures were seven plastic colored balls vertically stacked and suspended on a string from the overhead tank covers, while linear structures consisted of vertically-oriented aluminum rods. Weight gain and feed conversion ratio were significantly improved in the tanks with either of the environmental enrichment treatments compared to control tanks. Weight gain and feed conversion ratio were also significantly improved with the use of spherical structures compared to the use of linear structures. To provide substantial benefits during the rearing of Rainbow Trout in circular tanks, the use of vertically-suspended spherical structures is recommended.
... Environmental colour is an important factor to consider in the culture of fishes, as it is known to affect skin pigmentation in several species (Doolan et al., 2007;Fanourak et al., 2007;Eslamloo et al., 2015). Differences in tank colour can induce a variety of responses in relation to food intake and growth (Sunuma et al., 2009;Ullmann et al., 2011;Montajami et al., 2012;Duk-Young & Hyo-Chan, 2013), behaviour (Rodgers et al., 2010;Ishibashi et al., 2013), stress (Karakatsouli et al., 2007a;Barcellos et al., 2009;Banan et al., 2011) and other factors. ...
... In L. alexandri juveniles, the different environmental colours did not alter the plasma protein, triglyceride and cholesterol levels, similar to that which was also recorded for C. carpio (Papoutsoglou et al., 2000), Huso huso L. 1758 (Banan et al., 2011) and Carassius auratus (L. 1758) (Eslamloo et al., 2015) reared in different colour tanks. In contrast, the haematocrit level did vary and was greatest for fish kept in white tanks. ...
... The L. alexandri juveniles from the white and yellow tanks had a paler skin colour. Pale skin in farmed fish from white tanks is consistent with what has been reported during the cultivation of Melanotaenia australis (Castelnau 1875) (Rodgers et al., 2010), C. auratus (Eslamloo et al., 2015), Amphiprion ocellaris Cuvier 1830 (Yasir & Qin, 2009) and O. niloticus (Opiyo et al., 2014). ...
The growth, physiology and skin pigmentation of pacamã Lophiosilurus alexandri juveniles were evaluated in an experiment using different tank colours (white, yellow, green, blue, brown and black) over an 80 day period. The tank colours did not cause significant differences to final body mass, total length, survival rate, carcass composition (moisture, crude protein, ash, ether extract, calcium, phosphorus, energy), or to plasma protein, triglyceride and cholesterol values. Haematocrit values, however, were highest for fish kept in white tanks (ANOVA P < 0·05), while the greatest haemoglobin levels were recorded for fish kept in blue and brown tanks (P < 0·01). The concentrations of cortisol (P < 0·001) and glucose (P < 0·01) were the most in fish in the black tanks. Tank colour affected skin pigmentation significantly, with fish in white tanks having the highest values of L* (brightness) and the lowest values in blue and black tanks. L*, however, decreased in all treatments throughout the experiment. C*ab increased significantly over the course of the experiment in fish kept in white tanks. Similar increases of C*ab were recorded in the other treatments but to a lesser extent. The use of black tanks during the cultivation of L. alexandri caused stress and should be avoided. Cultivation in white and yellow tanks produced individuals with a pale skin colour, while cultivation in blue and black tanks resulted in juveniles with a darker and more pigmented skin.
... The ability of these fish to detect and ingest their food can be affected by a number of factors including background colour. Different coloured tanks induce a variety of responses in relation to growth, survival, skin colour, stress response, neural and hormonal processes, behaviour and feed acceptance, or their combined effects in fishes (Papoutsoglou et al. 2000;Tamazouzt et al. 2000;Rotllant et al. 2003;Papoutsoglou 2005;Jentoft et al. 2006;Strand et al. 2007;Luchiari and Pirhonen 2008;Pawar et al. 2011;Kang and Kim 2013;Raghavan et al. 2013;Eslamloo et al. 2015;Karakatsouli et al. 2015;Okada et al. 2015;Ustundag and Rad 2015;Zhang et al. 2015;Li et al. 2016;Sierra-Flores et al. 2016). For instance, Eurasian perch, Perca fluviatilis, grew best in light-grey tanks (Tamazouzt et al. 2000); juvenile guppies, Poecilia reticulata, had a higher specific growth rate in blue tank (Ruchin 2004); and juvenile rainbow trout, Oncorhynchus mykiss, reared in green environments had higher specific growth rates than those reared in blue, white or red tanks (Luchiari and Pirhonen 2008). ...
... These researchers found that dark background-adapted fish exhibited higher cortisol level and lower performance compared with fish adapted to white backgrounds. Similar to goldfish, Carassius auratus (Eslamloo et al. 2015) and rainbow trout (Rahnama et al. 2015), the lower growth and feed intake of taimen larvae in the red and black groups also may be related to stress responses. In the previous study, elevated levels of cortisol were continuously observed in the young taimen reared in light-red tanks throughout the experiment (Wang et al. 2016), and stress responses energy-demanding processes that may increase the catabolic processes of cultured fish, and may reduce their growth rates (Strand et al. 2007;El Sayed and El Ghobashy 2011) and survival (Okada et al. 2015). ...
... In the present study, taimen larvae seemed to prefer a yellow environment, similar to rainbow trout (Ustundag and Rad 2015) and Nile tilapia, Oreochromis niloticus (Luchiari et al. 2007), while red was better for zebrafish, Danio rerio (Spence and Smith 2008); blue for barramundi (Ullmann et al. 2011); white for goldfish (Eslamloo et al. 2015); dark blue and black for yellow catfish, Pelteobagrus fulvidraco (Raghavan et al. 2013); green for grouper, Epinephelus coioides (Zhang et al. 2015) and Atlantic cod (Sierra-Flores et al. 2016); and white and blue for turbot, Scophthalmus maximus ). Similar to barramundi (Ullmann et al. 2011), in red, black, and blue tanks, taimen larvae remained in relatively tight shoal; once fed, one or two individuals would commence feeding and then the whole shoal went to the water surface to feed. ...
This study was conducted to evaluate the effect of tank colour on growth and survival of taimen Hucho taimen larvae. Larvae (initial weight 0.11 ± 0.01 g, 21 days after hatching) were cultured in the water flow-through system. Fifteen aquaria (200 L per aquarium) were randomly allocated into triplicate groups of 500 larvae. The outsides of the tanks were covered in red, blue, yellow, white, or black sheeting. Larvae were fed eight times a day by hand to apparent satiation. The experiment was conducted for 56 days. The results showed that the specific growth rate was significantly affected by tank colour, which was higher in the yellow tank than that of the tank (black or red) (P < 0.05). The tank colour did not significantly affect survival, condition factor, and feed conversion ratio among all the treatments (P > 0.05). The highest feed intake was observed in fish reared in the yellow tank, followed by that of the white, blue, or black tank, and the lowest was in fish in the red tank. In conclusion, the light-coloured tank (yellow or white) was optimum for rearing taimen larvae based on the growth performance.
... Tank colour affects survival and growth performance (Bera et al., 2019;Ferosekhan et al., 2020;Pedreira & Sipaúba-Tavares, 2001;Sebesta et al., 2019;Tamazouzt et al., 2000). It also affects physiological processes and behavioural responses, such as feeding (Bera et al., 2019;El-Sayed & El-Ghobashy, 2011;Wang et al., 2016), digestion (Rungruangsak-Torrissen et al., 2006;Santisathitkul et al., 2020), body composition (Banan et al., 2011;Papoutsoglou et al., 2000), reproduction (Volpato et al., 2004), skin pigmentation (Eslamloo et al., 2015;Yasir & Qin, 2009) and stress response of fish larvae and juveniles (Banan et al., 2013;de Abreu et al., 2020;Sopinka et al., 2016;Wang et al., 2016). ...
... The larvae probably used a lot of energy/resources to control stress and/or to adapt to the environment, and in turn, showed reduced growth rates (Schreck & Tort, 2016). Similar results have been reported in cyprinids (Eslamloo et al., 2015;McLean, 2021). Contrary to snubnose pompano, when Nile tilapia (Oreochromis niloticus) and summer flounder (Paralichthys dentatus) ...
Snubnose pompano (Trachinotus blochii, Lacépède) is a commercially important fish species that shows robust growth in captive environment. Tank colour is an important factor affecting the growth of fish larvae in aquaculture. Although the effect of tank colour has been studied in several fish species, it has not been studied in the snubnose pompano. We aimed to investigate how tank colour affects overall growth, survival, body composition, stress levels and digestive enzyme activities of snubnose pompano larvae at early larval stage and late larval stage. We noted that early–larval–stage larvae showed higher growth, crude protein contents and lower digestive enzyme activities when reared in blue and white tanks. Larvae showed low‐stress levels when reared in grey and blue tanks. The same larvae showed low‐survival and high‐stress levels when reared in red tanks. The late–larval–stage larvae showed high growth and lipids, and low‐digestive enzymes activities in white and yellow tanks. The larvae showed high‐stress levels and low‐ash contents when reared in red tanks. These differences are most likely due to the differences in light intensity inside tanks, which affects the ability of larvae to find and catch prey. Overall, our study sheds new light on cultivation conditions for snubnose pompano larvae. We recommend blue tanks for growing early–larval–stage larvae and white or yellow tanks for late‐larval‐stage larvae.
... Serum glucose was assessed by the method outlined in Palti et al. (1999)). Lysozyme activity was assessed according to the method described by Eslamloo et al. (2015). Serum cortisol was determined by immunoassay technique using fish cortisol ELISA kit (Cusabio Biotech Co., LTD, China) according to the manufacture instructions. ...
... (Costa et al., 2017) stated that, in L. alexandri juveniles, the different environmental colors did not alter the plasma protein level. (Eslamloo et al., 2015) reported that rearing Carassius auratus (L. 1758) in different color tanks showed no significant effect on the total protein level. ...
This study aimed to evaluate the effects of different monochromatic LED light colors (blue “BL”, red “RL”, green “GL” and white “WL”) in addition to natural day light (NL) on the growth performance, behavior and immune-physiological responses of goldfish (Carassius auratus). Fish (N = 75, 4.483 ± 0.061 g) were arbitrarily allocated to five groups (BL, RL, GL, WL and NL) in triplicates and fed a commercial diet (400 g/kg crude protein, 80 g/kg crude lipid) for 2 months. There was a significant improvement in final body weight, weight gain, weight gain rate, feed conversion ratio, specific growth rate, length, hepato-somatic and viscerosomatic index of fish reared under BL in respect to the other tested groups (p ≤ 0.05). Fish reared in BL showed better behavior response in form of lower ventilation frequency, longer reaction time and swimming duration in the novel object test, as well as shorter latency to first movement in duration of appetite inhibition test compared to the other experimental groups (p ≤ 0.05). Immune-physiological responses were improved in fish reared under BL followed by GL in respect to the other groups (p ≤ 0.05). This was manifested by higher red blood cells, hemoglobin, total protein, albumin (A), globulin (G), A/G ratio, lysozyme activity, as well as lower neutrophils / lymphocytes ratio, glucose, and cortisol. Despite of absence of statistical significance effect of light color on the relative expression of transforming growth factor beta 1, tumor necrosis factor alpha and interleukin-1 beta 2 genes, slight up-regulation of immune-related genes was observed in the fish reared in BL. In conclusion, rearing of goldfish under monochromatic BL improves their performance, behavior, and immune-physiological responses to stress without any adverse effects on water quality.
... Relatively little is known about the impacts of colour on cultured fish. The colours used during hatchery rearing may affect feed intake, growth, aggression, stress response and body colouration (Volpato and Bareto, 2001;Strand et al., 2007;Qin et al., 2012;Eslamloo et al., 2015;Gaffney et al., 2016;Ghavidel et al., 2019). However, the effects of specific colours are not universal among species. ...
... While tanks containing the green angles produced significantly larger individual salmon, the possible influence of the turquoise-green rearing tank colour on these results is unknown. Other studies examining colour during rearing have focused on tank colours, rather than suspending novel colours within an already-coloured tank (Browman and Marcotte, 1987;Papoutsoglou et al., 2005;Strand et al., 2007;Eslamloo et al., 2015;Ghavidel et al., 2019). Similarly, studies examining the colour of lighting typically use tanks that are colourless, opaque, or match the lighting colouration (Karakatsouli et al., 2007(Karakatsouli et al., , 2008Banan et al., 2011;Elnwishy et al., 2012;Kawamura et al., 2017). ...
This study investigated the effects of coloured structures on the growth of juvenile landlocked fall Chinook salmon (Oncorhynchus tshawytscha, Walbaum) during hatchery rearing. Structures consisted
of an array of four aluminum angles painted one of four colours: Silver, red, black and green, which were vertically-suspended in circular tanks. After 25 days, mean total lengths and weights of individual
salmon reared in tanks with the green arrays were significantly (P < 0.05) larger than those reared with silver, red or black arrays. Condition factor was not significantly different (P > 0.05) among the colour
treatments. Final total tank biomass and gain were also not significantly different (P > 0.05) among the colour treatments. The results of this study indicate that structural colours could be considered to maximize juvenile Chinook salmon growth during hatchery rearing.
... Therefore, animals from a wide range of taxonomic groups can change their body color based on their background over a range of spatial and temporal scales, since camouflage through color change has ecological significance [5], as well as significance for the physiological processes in response to background stimuli [6]. In turtles and tortoises, some evidence of color preferences has been reported [7][8][9][10], however the majority of such studies have been conducted in fish [11][12][13][14][15]; no prior data are available regarding terrapins. ...
... Similar observations were also reported for common carp (Cyprinus carpio) [15] and for convict cichlid (Cichlasoma nigrofasciatum) [12] reared with various background colors for 14 and 8 weeks, respectively. On the other hand, significant effects of background color on growth have been reported in white sea bream (Diplodus sargus) [14], goldfish (Carassius auratus) [13], and starlet (Acipenser ruthenus) [11]. These prior studies indicate that the growth responses of animals to background color are species-specific. ...
Background color has significant effects on the lifestyles of various animal species. In this study, the effects of wall background color on growth, feed utilization, specific activity of gastric and pancreatic enzymes in fecal samples, fecal thermal properties, carapace elemental profile, and hematological parameters were investigated in northern river terrapin (Batagur baska Gray, 1831) in order to optimize the head-starting conditions. The terrapins (70.13 ± 0.04 g initial weight) were completely randomized into five types of colored tanks (transparent, green, red, blue, and black) and reared for twelve weeks. At the end of the experiment, tank color had no effect on survival and growth performance, but had significant effects on feeding rate, feed conversion ratio, and protein efficiency ratio (p < 0.05). Terrapins reared with black, red, or blue backgrounds had the highest feed utilization among the treatments. Among these three groups, analysis of specific activity of gastric and pancreatic enzymes in fecal samples and fecal thermal properties suggested improved digestive functionality in terrapins reared with a blue background relative to the other treatments. Carapace elemental composition and hematological parameters indicated no negative effects on health status of the terrapins reared with this optimal treatment. Findings from the current study support the head-starting program of northern river terrapins before release to natural habitats, and could also be applied in aquaria or zoos for public display.
... To measure glucose and cortisol level, 0.1 g of the whole crab was homogenized in 0.9 ml saline, and then centrifuged at 2,500 g to obtain a 10% tissue suspension. The glucose was tested with glucose oxidase method using a glucose assay kit (Nanjing Institute of Bioengineering, China; Eslamloo et al., 2015). In brief, samples were fixed with glucose oxidase, peroxidase, phosphate buffer, phenol and 4-aminoantipyrine, water bathed at 37°C. ...
... The speculation was also supported by the fact the crab cultured in white tank had higher cortisol level. High cortisol level were also found in yellow catfish Pelteobagrus fulvidraco (Raghavan et al., 2013), goldfish C. auratus (Eslamloo et al., 2015) and scaled carp C. carpio (Papoutsoglou et al., 2000) when cultured in suboptimum tank colour, leading to inferior growth performance. Though the crab in white tank had lower biomass compared with those cultured in red and blue tank, less cannibalism could be beneficial for the juvenile crab seedling. ...
... Kientz et al. (2018) used spheres of various colors in their vertically-suspended structures.This study was conducted in blue walled tanks and used only white PVC and spheres (golf balls) in enrichment structures. While the effects of color on rearing performance are not well understood, some tank wall colors have been associated with increased growth (Tamazouzt et al. 2000;Karakatsouli et al. 2007;Eslamloo et al. 2015). Ambient color can also increase ( Eslamloo et al. 2015) or decrease ( Volpato and Bareto 2001;Luchiari and Pirhonen 2008) stress in certain species of fish. ...
... While the effects of color on rearing performance are not well understood, some tank wall colors have been associated with increased growth (Tamazouzt et al. 2000;Karakatsouli et al. 2007;Eslamloo et al. 2015). Ambient color can also increase ( Eslamloo et al. 2015) or decrease ( Volpato and Bareto 2001;Luchiari and Pirhonen 2008) stress in certain species of fish. ...
Environmental enrichment is the use of structures or materials to create more natural or complex environments in hatchery rearing units. This study assessed the effects of two types of enrichment structures on the growth of juvenile landlocked fall Chinook salmon (Oncorhynchus tshawytscha) reared in semi-square tanks. The structures were vertically-suspended arrays of either five half-round polyvinyl chloride pipes or six golf balls affixed vertically on threaded rod (spherical enrichment). After 90 days, both enrichment treatments produced significantly greater weight gains than the unenriched control. Total fish length was significantly different among all three treatments, and was highest in fish reared with spherical enrichment. Individual weight, condition factor, and relative dorsal and pectoral fin length also differed between enriched tanks and the control, but did not significantly differ between enrichment types. The results of this study support the use of vertically-suspended enrichment structures to improve juvenile Chinook salmon growth during hatchery rearing.
... Two studies of goldfish Carassius auratus juveniles showed that the amount of cortisol decreases when exposed to green light and increases in red light (Jung et al. 2016;Song et al. 2016a). In other experiments (Eslamloo et al. 2015), also against the backdrop of the negative effect of red light on the growth of the same species, the concentration of cortisol increased, while in blue light and in the dark, the amount of cortisol was much lower. ...
... Light blue and blue zones of the spectrum had somewhat lesser growth-stimulating effect. Long-term studies (Eslamloo et al. 2015) showed that, in the first 6 weeks, the Carassius auratus fingerlings grew equally in different colour variations. However, at the 8th week, the difference became quite obvious. ...
... Environmental colors affect the vision of teleosts, influencing for example food intake, signals for hierarchical status, reproduction, growth and even survival (Downing, 2002;Politis et al., 2014;Karakatsouli et al., 2007;Luchiari and Pirhonen, 2008). The use of optimal light colors was described to decrease stress status and stressinduced cortisol response in several fish species (Volpato and Barreto, 2001;Karakatsouli et al., 2007;Eslamloo et al., 2015). Unnatural light spectra also negatively affect important aspects of larval development and performance (Villamizar et al., 2009;Blanco-Vives et al., 2010). ...
... Since opposite responses for lysozyme and peroxidase activities were observed when fish were reared under a red light spectrum, we are not able at this stage to define a clear trend (stimulation or inhibition) of the immune system. The only study found on immune regulation by the light spectrum in teleosts focused on goldfish (Eslamloo et al., 2015). This study revealed that a red or a blue environmental lights are chronically stressful and immunosuppressive with increase in plasma cortisol and decreases in lysozyme and plasma antiprotease. ...
... Hilken et al., 1995;Downing and Litvak, 1999), development (Cobcroft et al., 2012), feeding (e.g. Sherwin and Glen, 2003;Rahnama et al., 2015), immunosuppression (Eslamloo et al., 2015), mortality (e.g. El-Sayed and El-Ghobashy, 2011;Sykes et al., 2011;Ikhwanuddin et al., 2012), and behaviour (e.g. ...
... Here the impact of an ecologically relevant (black) or a nonecologically relevant (white) tank background on adult X. laevis was investigated. Responses to cage/tank colour in other species have been observed through changes in glucocorticoids (Barcellos et al., 2009;Banan et al., 2013), skin carotenoids (Höglund et al., 2002;Eslamloo et al., 2015), body mass (Sherwin and Glen, 2003), morphology (Cobcroft et al., 2012), and behaviour (Höglund et al., 2002). In a previous study changes in water-borne corticosterone, behaviour and body mass indicative of stress were observed following transportation of X. laevis (Holmes et al., Submitted 2016). ...
The captive environment of a laboratory animal can profoundly influence its welfare and the scientific validity of research produced. The African clawed frog (Xenopus laevis) is a common model organism, however current husbandry guidelines lack supporting quantitative evidence. The visual environment is a fundamental aspect of a captive animal’s housing and may affect a number of physiological and behavioural responses. This is particularly important for species such as X. laevis where cryptic camouflage is a fundamental defence mechanism. Here male (n = 16) and female (n = 20) X. laevis were housed in tanks with ecologically relevant (black) and non-relevant (white) background colours and physiological and behavioural responses observed. Higher levels of water-borne corticosterone were observed in tanks with a white background compared to a black background in females (p = 0.047). Increased atypical active behaviours (Swimming: p = 0.042; Walling: p = 0.042) and a greater degree of body mass loss (p < 0.001) were also observed in the white background condition. Together these responses are indicative of increased stress of X. laevis when housed in tanks with a non-ecologically relevant background compared to an ecologically relevant background and suggest refined tank background colour may improve welfare in this species.
... Oreochromis niloticus exhibits a high cortisol level when maintained on blue and brown backgrounds [15], and fish reared on a black background are distinctively darker than those reared on a white, blue, or clear background [16][17][18]. Furthermore, the background color could influence the capture of food and consumption, and consequently, the growth of the fish [19][20][21]. ...
Fish skin color is usually strongly affected by the background color of their environment. The study investigated the effects of five different background colors on the skin color of leopard coral groupers (Plectropomus leopardus). More than 450 juveniles were reared in Blue, Red, Black, White, and Transparent background tanks for 56 days. The paraffin section showed that the skin melanin zone of fish in the White group was smaller, whereas the Black and Red groups (especially Black) were nearly the largest. The apparent skin color of P. leopardus was red on the white background, which darkened in response to the other color backgrounds. The Black group revealed the blackest skin color, followed by the transparent group. Moreover, the White group had the highest L*, a*, and b* values. The melanin content and tyrosinase activity in the dorsal and ventral skin of the Black group were significantly higher than those in the other groups (p < 0.05), and the serum α-MSH level was higher in the Black group as well. The carotenoid and lutein contents showed completely different trends among the experimental groups, as carotenoid content was higher in the Red and White groups, while lutein content was higher in the Transparent group. The expression level of scarb1 was highest in the Blue and White groups, followed by the Transparent group, and lowest in the Black group (p < 0.05). The expression trend of scarb1 was similar to the skin color in different backgrounds, indicating that the background color regulated scarb1 expression level through visual center, then influenced the uptake and transport of carotenoids, then influenced the skin color formation of P. leopardus. Moreover, lighter colors inhibited the formation of melanocytes and had a significant effect on carotenoid and lutein contents. Pigment-related genes were involved in the regulation of fish skin color, and they were affected by background color in P. leopardus. These results indicate that a white background is more conducive to maintaining red skin color in juvenile P. leopardus.
... Color can affect fi sh growth, physiology, aggression, and stress response [1][2][3][4][5][6][7][8][9]. Color preferences can vary between fi sh species and can change in the same fi sh over time [10]. ...
This study evaluated the use of either blue or silver vertically-suspended environmental enrichment in two experiments, with one rearing Chinook salmon (Oncorhynchus tshawytscha) for 29 days and the other rearing rainbow trout (Oncorhynchus mykiss) for 98 days. In both experiments, there were no significant differences in total tank weight, gain, percent gain, feed conversion ratio, or percent mortality between tanks with either silver (unpainted aluminum) or blue vertically-suspended environmental enrichment. Individual fish total length, weight, specific growth rate, and condition factor were also not significantly different between the two colors for both fish species. These results indicate that either silver (unpainted aluminum) or blue vertically-suspended environmental enrichment can be used during the hatchery rearing of juvenile Chinook salmon or rainbow trout.
... It is well documented that any alteration in ambient environmental conditions, including the light spectrum, can lead to a stressful condition resulting in lower immune response in teleosts (Eslamloo et al., 2015;Wu et al., 2019). Generally, an increased expression of immune genes is considered as an indicator of immune stimulation or superior immune response (Abo-Al-Ela, 2018). ...
Present study was aimed to assess the effects of different light spectra on reproductive performance and mRNA expression of some immune and anti-oxidant defense genes in endangered golden mahseer. The relative fecundity of brooders and fertilization rate of eggs did not change due to different light spectra. Whereas there was significantly higher rate of hatching (%) of eggs and survival (%) of fry obtained from brooders reared in white and green light compared to blue light. No significant effect of light spectra was observed on the expression levels of il1β, il10, tlr5, and inos. There was a linear increase in the relative expression of serum amyloid A (saa) (Y = 1.980x – 0.118, R² = 0.972) and igl (Y = 1.077x + 0.093, R2 = 0.998) from white light to green light with maximum values found under green light. The mhc1 level was higher in white and green lights compared to blue spectra. A positive linear correlation was noticed between mRNA expression of crfb4 and hatching percentage (Y = 13.95x + 69.07, R² = 0.920) of the eggs as well as survival percentage of fry (Y = 0.054x – 3.520, R² = 0.985) obtained from brooders under different light spectra. The expression levels of all three anti-oxidative defense genes were significantly and similarly affected by light spectra. The maximum expression of anti-oxidative genes was registered in white light, and the minimum was observed in blue light. Overall, the results suggested a higher reproductive performance and immune status of golden mahseer female brooders reared under green light. Hence, green lights could be a better option for broodstock management of golden mahseer in captive conditions.
... However there are debates about the impacts of background color on fish pigmentation. Moreover, in ornamental fish sector several fish species like gold fish have been studied to show the effects of background color (Eslamloo et al. 2013). But there is no information available on their effects of background color on the growth performance and coloration of the Guppy fish. ...
A study was carried out to investigate the effects of background color on the growth, skin pigmentation and breeding performances of guppy, Poecilia reticulata. Guppy fish was reared in tanks with four different colors as treatments such as T0 (transparent), T1 (red), T3 (blue) and T4 (green) for 5 months. There were significant differences in growth and coloration among the treatments. The growth performance was found significantly higher in transparent background compared to the other treatments. The results showed that the highest mean weight (0.259 ±0.018 g), mean length (3.067±0.208 cm) and SGR (0.165±0.012) of the fish were significantly higher in T0. Least mean weight (0.167± 0.025 g), mean length (2.53±.0.058 cm) and SGR (0.104±0.017) were observed in T1 indicating association of red color with slower growth performance of guppy, compared to other treatments. Study showed significant influence of background color in skin pigmentation. Fishes reared in transparent tanks showed the highest value of carotenoid (0.00175±0.00004mg/g) and fishes reared in the red tank showed the lowest value of carotenoid (0.00092±0.000035 mg/g). Green background enhanced red orange color on fish skin and provided high amount of carotenoid value (0.00143±0.000046 mg/g) than that with blue (0.00095±0.000025 mg/g). These results suggest significant influence of background color on growth and skin pigmentation patterns of Guppy.
... There is a conventional method of stimulating the skin colouration easily (Eslamloo et al. 2015), that of rearing ornamental fish in a tank or pond containing carotenoid-rich algae, where the fish can achieve the required skin colouration. Although this method is simple, it cannot guarantee the stability of colour and sometimes creates water quality problems. ...
Attractive colouration of ornamental fishes is an important quality criterion in the aquarium fish industry. Ornamental fish cannot synthesize colour-producing carotenoid pigments and therefore must rely on dietary carotenoids in natural or synthetic forms to achieve their colour pigmentations. The aim of this review is to compile and summarize recent investigations into different carotenoid sources used in ornamental fish feed formulations and to highlight the research gaps and investigation needs in the field of aquaculture. The natural carotenoid sources which have been widely used for enhancing colouration are non-photosynthetic organs of higher plants, microalgae, seaweeds, crustacean by-products, and red yeast. Consumers mostly prefer to use natural sources rather than synthetic sources. The problem faced by aquaculturists is stabilization of the gained skin colour after terminating feeding of the fish. Advanced investigations are needed to identify the stability of the colouration in the ornamental fish during their life cycle. Further, this review encourages the use of other available natural carotenoid sources in the ornamental fish industry in order to reduce the use of synthetic pigment products and invites research to be done on a genetic level in order to fully understand colour distribution patterns and sustainability of colouration gain.
... Blue has been shown to negatively affect the growth of rainbow trout (Oncorhynchus mykiss), but positively affect the growth of gilthead seabream (Sparus aurata) [7]. Pale colored tanks (white or beige) have led to increased weight gain in goldfish (Carassius auratus) [4] and rainbow trout [8], but negatively impacted weight gain in African catfish (Heterobrachuys bidorsalis) [9]. ...
This study examined the effects of five different colors of vertically-suspended environmental enrichment on the growth of juvenile Shasta strain rainbow trout (Oncorhynchus mykiss) during hatchery rearing in circular tanks. The colors used were silver (unpainted aluminum-control), safety red, semi-gloss black, hunter green, and safety blue. After 86 days, total tank weight, weight gain, and feed conversion ration were not significantly different among any of the color treatments. Individual fish weights, lengths, and condition factors were also not significantly different among the treatments. The results of this study indicate that the relatively small amount of color present on the suspended structure did not affect rainbow trout growth. Thus, the inherent silver color of the aluminum angles does not need to be changed.
... A similar study was carried out with juveniles of rainbow trout (Oncorhynchus mykiss) using tanks in beige, grey, dark and light green colour (Ustundag and Rad, 2015). Experiments in this field were conducted with perch (Perca fluviatilis) by Tamazouzt et al. (2000), Caspian kutum (Rtilusfrisii кutum) by Imanpoor and Abdollahi (2011) Effect of different tank colours on some productive parameters of European catfish (Silurus glanis L.) fingerlings Eslamloo et al. (2013), African catfish (Heterobranchus bidorsalis) by Solomon and Ezigbo (2018), Chinese yellow catfish (Pelteobagrus fulvidraco) by Raghavan et al. (2013), African catfish (Clarias gariepinus) by Bardocz et al. (1999), Dada (2009), Ekokotu and Nwachi (2014) and Okomoda et al. (2017). ...
... These cells have the ability to adjust the animal color in different situations (Grempel and Visconti, 2014). Environmental factors, such as background color and lighting from sunlight, can affect the lightness of fish skin (Matsui et al., 1992;Eslamloo et al., 2015;Ninwichian et al., 2018). The darker coloration of the BFT system water (high turbidity) may have reduced the lightness of the goldfish skin. ...
This study evaluated the effect of biofloc technology (BFT) system and the astaxanthin supplementation on the productive performance and skin pigmentation of goldfish (Carassius auratus). The effects of two production systems (clear water and BFT) and two diets (with and without astaxanthin supplementation) were evaluated in a completely randomized 2 × 2 factorial design. A total of 120 goldfish juveniles (average weight 12.18 ± 0.27 g) were individually weighted and distributed into 24 glass aquariums (15 l of useful volume). Two isoproteic (40% of crude protein) and isoenergetic (4250 kcal of gross energy kg⁻¹) diets were formulated according to requirements established for goldfish. A control diet without carotenoid supplementation was compared with a diet supplemented with 80 mg kg⁻¹ of astaxanthin. After 56 days, fish growth and skin pigmentation parameters were evaluated. No interaction (system x diet) was observed for any of the evaluated variables. Production systems and astaxanthin dietary supplementation had no effects on weight gain (4.00 g), specific growth rate (0.51% day⁻¹), survival (98.33%) and apparent feed conversion (3.78) of fish. Redness (a) and yellowness (b) values were higher in the fish reared in BFT system (a 7.71, b 40.47) when compared to clear water (a 3.49, b 37.63), and in fish fed with the diet containing astaxanthin (a 6.46, b 40.72) in relation to control diet (a 4.74, b 37.38). Skin carotenoid concentration was also higher in fish produced in the BFT system (50.36 mg kg⁻¹) when compared to clear water (35.63 mg kg⁻¹) and fish fed with the astaxanthin diet (49.33 mg kg⁻¹) in relation to the diet with no supplementation (36.66 mg kg⁻¹). These results demonstrate that the BFT system is an effective and promising technology for goldfish (Carassius auratus) production. The BFT system promotes pigmentation, but this effect can be intensified with exogenous sources of carotenoids.
... At the same time, it is the least studied parameter in the larval production. There were only few studies explaining about the influence of tank background colour on larval performance and health including Australian snapper, Pagrus auratus (Doolan et al., 2009), thin lip mullet, Liza ramada (El-Sayed and El-Ghobashy, 2011), Amazon river prawn, Macrobrachium amazonicum (Maciel and Valenti, 2014), Pacific bluefin tuna, Thunnus orientalis (Okada et al., 2015), goldfish, Carassius auratus (Eslamloo et al., 2015), Milk fish, Chanos chanos (Bera et al., 2019). However, the effect of tank background colour on larval growth, survival and fry production is not studied for Asian catfish species such as magur and pangas. ...
Larval growth and survival are significantly influenced by the various biotic and abiotic factors. Rearing tank background colour is one such factor affecting the larval production in finfish hatcheries. The present study evaluated the effect of five tank background colours (black, white, blue, green and red) on growth and survival of larvae of two commercially important freshwater catfish species, Clarias magur (magur) and Pangasius pangasius (pangas) in a completely randomized experimental design in triplicate. The larvae of magur (9.33 ± 0.15 mm; 3.85 ± 0.05 mg) and pangas (10.07 ± 0.27 mm; 3.31 ± 0.08 mg) were stocked at a density of 45 and 30 larvae per tank, respectively in 15 L tanks. Experimental duration was 28 days for both the species. The results revealed that the final weight, weight gain, daily weight gain, and specific growth rate (SGR) of larvae of magur were significantly (P < 0.05) higher in white background coloured tank whereas, pangas shown the best performance (P < 0.05) in black tank. Thermal growth coefficient (TGC) of magur and pangas were recorded significantly higher in white and black coloured tank, respectively. Larval survival was significantly (P < 0.05) higher in black (97.04 ± 1.96%; F (4, 10) = 2.95, P = 0.002) tank for magur and green tank (87.78 ± 4.84%; F (4, 10) = 8.28, P = 0.003) for pangas. Whereas green and black tank colour were significantly reduced the larval survival of magur and pangas, respectively. This study clearly indicates that tank background colour had a significant impact on the larval growth and survival in both the species studied. It was also noticed that the tank colour effect is species specific. The study thus showed that black background tank colour for magur and green tank for pangas are more suitable for the higher production of catfish larvae in hatchery.
... Papoutsoglou, Mylonakis, Miliou, Karakatsouli, and Chadio (2000) reported that fish reared in black tanks had significantly higher plasma cortisol levels than those reared in white tanks, and specific growth rate and final weight was significantly higher and feed conversion ratio significantly lower in white tanks. This was also observed by Eslamloo, Akhavan, Eslamifar, and Henry (2015), Rahnama, Heydarnejad, and Parto (2015), Wang et al. (2016), and Wang et al. (2017). On the contrary, Downing and Litvak (2000) and Martin-Robichaud and Peterson (1998) found larvae reared in dark coloured tanks to show lower stress levels, higher food intake, and less body damage. ...
A 33-day experiment was carried out to investigate the effect of light at 80, 380, and 3800 lux and tank wall colour (black, grey, white, red, green, blue, clear) separately and in combination on growth, survival, yield, and size heterogeneity of peled Coregonus peled larvae. 7 groups of larvae in 3 repetitions were transferred to the experimental system. Each group comprised 300 larvae. Larvae were fed fresh live brine shrimp Artemia salina and artificial dry food LARVIVA ProWean. Significantly higher (p<0.05) survival was observed in black and white tanks in comparison with grey tanks. Significantly lower (p<0.05) size heterogeneity was observed in red and grey tanks compared to clear, black, green, and blue tanks, and in RD-H compared to WH-H, WH-M, WH-L, CL-H, CL-M, CL-L, BK-H, BK-M, BK-L, GN-H, GN-M, GN-L, BE-H, BE-M, BE-L, GY-H, and RD-M compared to WH-M, WH-L, CL-H, CL-M, CL-L, BK-H, BK-M, BK-L, GN-H, GN-M, GN-L, BE-H, BE-M, BE-L, and RD-L, GY-L, GY-M compared to WH-L, CL-H, CL-M, CL-L, BK-H, BK-M, BK-L, GN-H, GN-M, GN-L, BE-H, BE-M, BE-L. Based on our results, peled larvae are independent of light intensity. Rearing of peled in black tanks can be recommended for the highest survival.
... Recent studies have been devoted to understand the effects of background colors on hatchability and survival of tilapia larvae (Brian 2015), growth performance of fingerlings (Elnwishy et al. 2012), and social stress of juveniles (Merighe et al. 2004). Moreover, studies on the influence of background color in the performance of various fish species have been reported (Papoutsoglou et al. 2000;Tamazouzt et al. 2000;Volpato and Barreto 2001;Imanpoor and Abdollahi 2011;Eslamloo et al. 2013). These studies indicate that environmental colors have significant effects on the overall welfare of various fish species. ...
High fish mortality caused by poor management and conventional transport practices is still a major concern for tilapia hatchery operators. This study evaluated the effect of four transport management schemes (conditioning period, salt-treated water, background color, and their combination) on the survival of Nile tilapia (Oreochromis niloticus L.) fingerlings (0.27 ± 0.07 g) during transport. The test fish were subjected to simulated transport experiments using a manually operated carrier at 6-h, 12-h, 24-h, and 48-h transport time. In experiment 1, four treatment groups (6-h, 12-h, 24-h, and 48-h conditioning time) were compared. Treatments of varying salt concentrations (0, 4, 8, and 12 g L-1) in the transport water were utilized for experiment 2. In experiment 3, different colors of transport bags (transparent, black, blue, and red) served as treatments. The most effective treatments in the preceding experiments were combined and designated as treatments for experiment 4. Results of the series of experiments showed that 48-h transport time, conditioning of 24-h before transport (78.50 ± 4.23% survival rate), addition of 4 g L-1 salt to transport water (70.30 ± 12.64%), use of blue transport bag (93.80 ± 1.48%), and the combination of these three variables (99.50 ± 0.38%) were significantly effective (P < 0.05) in improving the survival rate of the fish. The present study provides alternative methods for further refinement on transport management protocols to enhance survival of Nile tilapia fingerlings during transport.
... Recent studies have been devoted to understand the effects of background colors on hatchability and survival of tilapia larvae (Brian 2015), growth performance of fingerlings (Elnwishy et al. 2012), and social stress of juveniles (Merighe et al. 2004). Moreover, studies on the influence of background color in the performance of various fish species have been reported (Papoutsoglou et al. 2000;Tamazouzt et al. 2000;Volpato and Barreto 2001;Imanpoor and Abdollahi 2011;Eslamloo et al. 2013). These studies indicate that environmental colors have significant effects on the overall welfare of various fish species. ...
High fish mortality caused by poor management and conventional transport practices is still a major concern for tilapia hatchery operators. This study evaluated the effect of four transport management schemes (conditioning period, salt-treated water, background color, and their combination) on the survival of Nile tilapia (Oreochromis niloticus L.) fingerlings (0.27 ± 0.07 g) during transport. The test fish were subjected to simulated transport experiments using a manually operated carrier at 6-h, 12-h, 24-h, and 48-h transport time. In experiment 1, four treatment groups (6-h, 12-h, 24-h, and 48-h conditioning time) were compared. Treatments of varying salt concentrations (0, 4, 8, and 12 g L-1) in the transport water were utilized for experiment 2. In experiment 3, different colors of transport bags (transparent, black, blue, and red) served as treatments. The most effective treatments in the preceding experiments were combined and designated as treatments for experiment 4. Results of the series of experiments showed that 48-h transport time, conditioning of 24-h before transport (78.50 ± 4.23% survival rate), addition of 4 g L-1 salt to transport water (70.30 ± 12.64%), use of blue transport bag (93.80 ± 1.48%), and the combination of these three variables (99.50 ± 0.38%) were significantly effective (P < 0.05) in improving the survival rate of the fish. The present study provides alternative methods for further refinement on transport management protocols to enhance survival of Nile tilapia fingerlings during transport.
... Recent studies have been devoted to understand the effects of background colors on hatchability and survival of tilapia larvae (Brian 2015), growth performance of fingerlings (Elnwishy et al. 2012), and social stress of juveniles (Merighe et al. 2004). Moreover, studies on the influence of background color in the performance of various fish species have been reported (Papoutsoglou et al. 2000;Tamazouzt et al. 2000;Volpato and Barreto 2001;Imanpoor and Abdollahi 2011;Eslamloo et al. 2013). These studies indicate that environmental colors have significant effects on the overall welfare of various fish species. ...
High fish mortality caused by poor management and conventional transport practices is still a major concern for tilapia hatchery operators. This study evaluated the effect of four transport management schemes (conditioning period, salt-treated water, background color, and their combination) on the survival of Nile tilapia (Oreochromis niloticus L.) fingerlings (0.27 ± 0.07 g) during transport. The test fish were subjected to simulated transport experiments using a manually operated carrier at 6-h, 12-h, 24-h, and 48-h transport time. In experiment 1, four treatment groups (6-h, 12-h, 24-h, and 48-h conditioning time) were compared. Treatments of varying salt concentrations (0, 4, 8, and 12 g L-1) in the transport water were utilized for experiment 2. In experiment 3, different colors of transport bags (transparent, black, blue, and red) served as treatments. The most effective treatments in the preceding experiments were combined and designated as treatments for experiment 4. Results of the series of experiments showed that 48-h transport time, conditioning of 24-h before transport (78.50 ± 4.23% survival rate), addition of 4 g L-1 salt to transport water (70.30 ± 12.64%), use of blue transport bag (93.80 ± 1.48%), and the combination of these three variables (99.50 ± 0.38%) were significantly effective (P < 0.05) in improving the survival rate of the fish. The present study provides alternative methods for further refinement on transport management protocols to enhance survival of Nile tilapia fingerlings during transport.
... Although the spheres were colored in this study, the possible effect of color on trout growth and behavior is unknown. Other studies have indicated tank wall color can influence fish growth (Tamazouzt et al. 2000;Karakatsouli et al. 2007;Eslamloo et al. 2015), but color preferences may be species-specific (Volpato and Barreto 2001;Luchiari and Pirhonen 2008;Batzina et al. 2014). ...
Environmental enrichment is the addition of substrate or structural complexity to typically sterile culture environments, but the effects of enrichment on fish rearing performance are relatively unknown. This 127‐d study examined the growth and condition of juvenile Rainbow Trout Oncorhynchus mykiss reared in near‐fully covered circular tanks (1.8 m diameter) with three novel environmental treatments: (1) eight vertically suspended nylon strings with seven colored (6.4 cm diameter) plastic spheres (high density), (2) five vertically suspended strings with seven colored plastic spheres (low density), and (3) a mixture of five vertically suspended colored plastic spheres and nine vertically suspended aluminum rods. Near‐fully covered tanks without enrichment were used as a control. Weight gain, feed conversion ratio, individual fish length, and fish weight were significantly improved in environmentally enriched tanks compared with those features in the unenriched control. Among all of the treatments, the tanks of fish with high‐density spheres had significantly higher ending tank weights (i.e., total weight of fish in tank) and weight gain, both of which were nearly 65% and 75% greater, respectively, than in the control tanks. However, high density spheres also interfered with the self‐cleaning nature of the circular tanks. No significant differences in splenosomatic indices, viscerosomatic indices, hepatosomatic indices, and relative fin lengths were observed among the three enrichment treatments. Based on the results of this study, the use of either low‐density spheres or a mix of rods and spheres is recommended during the rearing of juvenile Rainbow Trout in circular tanks.
... -Jari-jari sirip anal mulai mengeras dan terlihat lebih jelas (The fin spines of anal fin more hardened and cleared ) -Pembelokan tulang ekor 45° (The deflection of notochord was ) (Rotllant et al., 2003;Eslamloo et al., 2013). Warna latar belakang berbeda ditangkap oleh mata dan kelenjar pineal ikan, sehingga bisa memodulasi sekresi hormon melatonin, a-melanocyte-stimulating hormone (aMSH) (Rotllant et al., 2003) dan hormon konsentrat melanin (KIA) (Amiya et al., 2005). ...
Rainbow kurumoi (Melanotaenia parva) merupakan salah satu ikan endemik Indonesia yang berasal dari Danau Kurumoi, Papua. Ikan ini merupakan salah satu komoditas potensial untuk perdagangan ikan hias. Akan tetapi, pemenuhan permintaan ikan rainbow masih mengandalkan hasil tangkapan alam. Rekayasa lingkungan diperlukan untuk meningkatkan produksi ikan rainbow ini. Penelitian ini bertujuan untuk mengetahui warna wadah yang sesuai untuk optimalisasi pemeliharaan larva ikan rainbow kurumoi. Perlakuan dalam penelitian ini adalah: A) warna wadah merah; B) warna wadah biru; dan C) warna wadah hijau. Larva dipelihara dalam wadah volume 4 L dengan kepadatan 20 ekor/L selama 28 hari. Pakan yang diberikan berupa infusoria, Rotifer, Artemia, dan Moina secara bertahap dengan metode ad libitum. Hasil penelitian menunjukkan bahwa larva yang diberikan perlakuan beda warna wadah tidak berbeda nyata (P>0,05) terhadap pertumbuhan dan sintasan. Perlakuan A (warna wadah merah) menunjukkan laju pertumbuhan spesifik panjang tertinggi yaitu sebesar 2,2 ± 0,1%/hari; dilanjutkan perlakuan B (2,1 ± 0,7%/hari); dan terakhir perlakun C (1,8 ± 0,7%/hari). Untuk laju pertumbuhan spesifik berat pada perlakuan A sebesar 6,7 ± 1,2%/hari; diikuti perlakuan C (6,4 ± 0,3%/hari) dan perlakuan B (5,5 ± 1,6%/hari). Perkembangan sirip sudah lengkap pada umur 27 hari setelah menetas dengan panjang total tubuh (TL) berkisar antara 8,0-8,6 mm.
Rainbow kurumoi (Melanotaenia parva) is one of endemic fish from Kurumoi Lake, Papua, Indonesia. The fish is considered one of the potential commodities in the ornamental fish market. However, to supply the demand for rainbow fish still relies on wild capture. Environmental manipulation is needed to improve the production of rainbow fish. The aim of this study was to evaluate the effects of tank color on the growth of kurumoi rainbow larvae. The treatments in this study were: A) red; B) blue; and C) green tanks. The larvae were reared in the 4 L volume tanks with a density of 20 ind./L for 28 days. The larvae were fed, in stages, with infusoria, Rotifer, Artemia, and Moina with ad libitum method. The results showed that the red tank (A) had the highest specific growth rate of length (2.2 ± 0.1%/day) followed by blue (B) (2.1 ± 0.7%/day) and green (C) (1.8 ± 0.7%/day) tanks. The red tank (A) had the highest specific weight growth rate (6.9 ± 1.2%/day) followed by the green (C) (6.4 ± 0.3%/day) and the lowest was blue (B) (5.5± 1.6%/day) tanks. The larvae maintained in the red tanks showed brighter color than that of the other two tanks. The fins development has completed on 27 days after hatching (8.0-8.6 mm TL) [ FOR WHICH TANK]. This research indicates that the tank colors do not have any influence on the growth and survival (P>0.05) of rainbow kurumoi larvae.
... Recent studies have been devoted to understand the effects of background colors on hatchability and survival of tilapia larvae (Brian 2015), growth performance of fingerlings (Elnwishy et al. 2012), and social stress of juveniles (Merighe et al. 2004). Moreover, studies on the influence of background color in the performance of various fish species have been reported (Papoutsoglou et al. 2000;Tamazouzt et al. 2000;Volpato and Barreto 2001;Imanpoor and Abdollahi 2011;Eslamloo et al. 2013). These studies indicate that environmental colors have significant effects on the overall welfare of various fish species. ...
High fish mortality caused by poor management and conventional transport practices is still a major concern for tilapia hatchery operators. This study evaluated the effect of four transport management schemes (conditioning period, salt-treated water, background color, and their combination) on the survival of Nile tilapia (Oreochromis niloticus L.) fingerlings (0.27 ± 0.07 g) during transport. The test fish were subjected to simulated transport experiments using a manually operated carrier at 6-h, 12-h, 24-h, and 48-h transport time. In experiment 1, four treatment groups (6-h, 12-h, 24-h, and 48-h conditioning time) were compared. Treatments of varying salt concentrations (0, 4, 8, and 12 g L-1) in the transport water were utilized for experiment 2. In experiment 3, different colors of transport bags (transparent, black, blue, and red) served as treatments. The most effective treatments in the preceding experiments were combined and designated as treatments for experiment 4. Results of the series of experiments showed that 48-h transport time, conditioning of 24-h before transport (78.50 ± 4.23% survival rate), addition of 4 g L-1 salt to transport water (70.30 ± 12.64%), use of blue transport bag (93.80 ± 1.48%), and the combination of these three variables (99.50 ± 0.38%) were significantly effective (P < 0.05) in improving the survival rate of the fish. The present study provides alternative methods for further refinement on transport management protocols to enhance survival of Nile tilapia fingerlings during transport.
... The carotenoid content of the skin in some ornamental fish is crucial because it would affect acceptability by consumers. In a recent study, Eslamloo et al. (2015) have stated that background colour could affect goldfish skin pigmentation. The carotenoid concentration in the skin significantly decreases in white background in comparison with the other groups. ...
This study aims to evaluate the effects of adding salt to water on the physiological parameters of the blood parrot cichlid (Cichlasoma synspilum ♀ × Cichlasoma citrinellum ♂). The blood parrot cichlid is a popular species in the aquarium trade because of its behaviour and beauty. Salt is usually added to water during the culture or transportation of this fish. However, the manner by which the fish adjusts its physiological responses to salinity change is unclear. The effects of salinity on serum osmolality, immune-related enzyme activities, Na+–K+-ATPase activities in the gill, skin carotenoid content and oxygen consumption were analysed. Blood parrotfish individuals were transferred from freshwater to water with four salinity levels (0.16, 2.5, 5 and 7.5 ‰) for 168 h, and physiological responses were evaluated at 0, 6, 12, 24 and 168 h. Results showed no significant differences in serum acid phosphatase and alkaline phosphatase activities, skin carotenoid content and oxygen consumption rate among the different groups. However, the serum osmolality at 6 h was significantly elevated. Moreover, salinity increase stimulated superoxide dismutase (SOD) activity from 0 to 6 h. SOD activity increased from 6 to 24 h but significantly reduced at 168 h when the fish were exposed to salt water. The SOD activity in the salinity 2.5 ‰ group recovered the initial level, whereas those in the salinity 5 and 7.5 ‰ groups decreased to levels lower than the initial level. The gill Na+–K+-ATPase activity significantly declined with time and salinity increase. Thus, adding an appropriate amount of salt can save energy consumption during osmoregulation and temporarily enhance the antioxidant activity of blood parrotfish. However, this strategy is insufficient for long-term culture. Therefore, adding salt to water only provides short-term benefit to blood parrot cichlid during transportation.
A wide range of functions in animal species depends on the pattern of color. The pigmentation pattern in fish depends on the spatial combination and number of chromatophore types. Color in the animal also depends on the species. During life, color can change, and the changes are a response to abiotic and biotic environmental factors. Nutritional quality, UV light incidence, the intensity of light, and social interactions also change the pigmentation pattern in fishes. Quality criteria decide the market value of ornamental fish species, and culture species for fish is the pigmentation system of the skin. The external signal infers its condition of culture and its welfare. The pattern of pigmentation defects is a significant cause of loss in aquaculture production. In the case of fish exhibiting diverse pigmentation patterns, the pigmentation pattern depends on the stage of development. Despite the use of various methodologies to enhance the production of freshwater and marine water species, pigment abnormalities are still being reported at higher rates in larvae. The reason for pigmentation abnormalities is unknown; the most probable cause for the color abnormalities is the interaction between genetic and environmental factors.KeywordsPigmentationChromatophoresPhotoreceptorMelaninα-MSH
This study focused on the effects of tank color on the growth, survival rate, stress response and skin color of juvenile hybrid catfish (Clarias macrocephalus × Clarias gariepinus) reared in tanks of 5 different colors (white, red, green, blue and black). Experiments were performed in triplicate with a duration of 8 weeks. Growth performance, feed utilization efficiency, survival rates, stress levels (as indicated by hematocrit, blood glucose, and plasma cortisol levels) and skin color parameters were evaluated in this study. Fish reared in red tanks exhibited a significantly higher mean final body weight (FBW) (27.50 ± 0.26 g), greater weight gain (WG) (18.57 ± 0.30 g), and a higher specific growth rate (SGR) (2.08 ± 0.03% per day) than those reared in tanks of other colors (P < 0.05). In addition, fish reared in red tanks had the lowest mean feed conversion ratio (FCR) (1.23 ± 0.05), which was significantly different from those reared in green (1.86 ± 0.10), blue (1.88 ± 0.04), and black (1.88 ± 0.16) tanks (P < 0.05). Fish reared in red (95.55 ± 2.22%) and blue tanks (95.56 ± 4.44%) had higher survival rates (SR) than fish reared in white (93.33 ± 3.85%), green (84.44 ± 5.88%) and black (80.00 ± 3.85%) tanks. The survival rates of fish reared in red and blue tanks were significantly higher than those reared in black tanks (P < 0.05). The stress indicators revealed the highest levels of hematocrit for fish reared in green tanks (41.80 ± 2.26%), followed by those reared in black (37.86 ± 2.19%), blue (37.76 ± 4.24%), red (36.38 ± 2.39%), and white (31.06 ± 4.45%) tanks. Of these, the fish reared in green tanks had a significantly higher mean hematocrit level than those reared in white tanks (P < 0.05). The plasma cortisol levels of fish reared in red tanks (18.73 ± 4.48 nmol/L) were lower than those reared in tanks of other colors. The skin color of fish reared in white tanks was the lightest (grayish–brown and yellowish–white), followed by fish reared in red, green, blue, and black tanks, which had the darkest skin color (black). This study demonstrated that the lightness (L*) of the tank color had an effect on fish skin color (74%). The assessment of growth performance, feed utilization efficiency, survival rate, stress responses, and skin color indicated that red is the most appropriate tank color for rearing hybrid catfish.
Yellow gourami (Trichopodus trichopterus) is a species native to Southeast Asia and is famous as ornamental species. However, hobbyists and farmers encounter problems where its body colour easily becomes faded in captivity. Since colour enhancer pellets are expensive, an experiment was performed to determine whether tank colour can influence the body colour intensity and growth of T. trichopterus. Four different tank colours (white, yellow, blue and green) with five replicates were tested where fish were kept under natural lighting (outdoor) conditions for two months. The results demonstrated that fish reared in green coloured tank showed an increment in its colour intensity while fish reared in white tanks increased its body weight. It can be concluded that tank colour does affect the body colour intensity and weight of T. trichopterus. This study will help farmers and hobbyists to solve colour fading problem using a cheaper way.
Sustainable aquaculture of the Japanese eel Anguilla japonica requires an understanding of the physiological conditions of the fish under culture conditions. Therefore, we examined the effects of tentative stressors such as background color and rearing density on stress-related hormones in juvenile Japanese eel. In Experiment 1, fish were divided into white- or black-coated tanks and reared for 35 days. Plasma cortisol levels were significantly higher in the white-acclimated fish on day 35. No significant differences were observed between the groups in hypothalamic CRH mRNA levels. In Experiment 2, fish were divided into three rearing density groups (0.5 kg/m2, 1.2 kg/m2, and 2.4 kg/m2) and reared for 28 days. Plasma cortisol levels were significantly lower in the low-density-acclimated fish than in the medium- and high-density-acclimated fish. However, no significant differences were observed in hypothalamic CRH mRNA levels. Evaluation of plasma cortisol levels indicates that a white background and high rearing density induce more stress for juvenile Japanese eel.
Careful examinations of the development and evolution of ornamental goldfish suggest that the goldfish domestication process is a unique and powerful platform for addressing questions and problems regarding the relationship between genotype and phenotype. In order to generalize the findings from this model system, pertinent questions and problems are further examined in this chapter, taking into account several topical hypotheses and concepts in the fields of evodevo. First, the limitations of positing a one-to-one relationship between genes and phenotypes are demonstrated in several schematic drawings, which represent developmental processes that mediate the translation of genotypes to phenotypes (Garstang, Zool J Linnean Soc 35(232):81–101, 1922) and the modular relationships between them (Wagner and Altenberg 1996). Based on these schemes, this chapter also explores how perturbations, genetic background, and developmental processes interrelate during the establishment of ornamental goldfish strains. To further explore how domestication of ornamental goldfish may continue in the near future and the biological meanings of these trends, I also discuss how artificial selection and genome editing for ornamental purposes might influence the modular relationship between genotypes and phenotypes.
Various different types of goldfish strains have been established by breeders and fanciers. Although these phenotypically different goldfish strains were previously grouped into different categories by researchers, there is no consensus among the manner of categorization for ornamental goldfish strains. Moreover, there is no standard nomenclature system for ornamental goldfish strains, leading to confusion about how to use variations of ornamental goldfish strains as research models. To avoid confusion arising from uncertain categorization and nomenclature systems, I first define the standard wild-type goldfish and provide detailed descriptions about its phenotypic features, in accordance with textbooks of vertebrate anatomy that examine mutated morphological features. Moreover, based on the skeletal anatomical characteristics, I categorize currently known goldfish strains into three representative morphotypes: single-tail, twin-tail, and dorsal-finless. Furthermore, comprehensive methods to describe all varieties of ornamental goldfish strains and their polymorphic features are provided by applying a character matrix-based method.
Appropriate light conditions in aquaculture systems are essential for fish welfare. Light spectrum, as one of the main characteristics of light, has a significant influence on the performance of teleosts. The development of light emitting diode (LED) technology allows for the precise regulation of light spectrum. This study examined the influence of five different LED spectra, red, orange, green, blue and full spectrum (white) on the performance of juvenile Scophthalmus maximus (seven months post hatching), by analyzing specific growth rate (SGR), feed conversion ratio (FCR), serum glucose and lactate contents, hepatic glycogen contents, antioxidative activity and pathogen resistance. A statistically higher SGR was observed in the blue group compared with the red, orange and white groups. Juveniles exposed to blue spectrum exhibited the lowest FCR. Juveniles exposed to red and orange light exhibited increased hepatic hsp70 mRNA levels, as well as increased mRNA expression levels of copper/zinc superoxide dismutase (cu/zn-sod), manganese superoxide dismutase (mn-sod), catalase (cat), glutathione peroxidase (gsh-px) and lysozyme (lzm). However, hepatic and serum total superoxide dismutase (T-sod), Cat and Gsh-px activities were not significantly higher in the red and orange groups. Hepatic Lzm activity was lowest in the red group. There were no significant differences in serum protein carbonyl (PC) and malondialdehyde (MDA) contents. No statistical difference was recorded in blood lactate levels between the five groups. Turbot under red and orange light may have higher carbohydrate metabolism levels, characterized by higher blood glucose and hepatic glycogen content. Overall, the results of the current study suggested that light spectrum had a significant effect on the performance of juvenile turbot, with growth retardation, together with decreased antioxidative activity and pathogen resistance observed in the red and orange groups. Juveniles under blue spectrum exhibited the best growth performance, antioxidative activity and pathogen resistance. Thus, blue spectrum is suggested for rearing juvenile turbot and improving fish welfare in aquaculture systems.
The welfare of farmed fish is an important issue in aquaculture. There is particular concern regarding ambient light in culture systems. In the current study, turbot (Scophthalmus maximus) larvae were exposed to four different light spectra: full spectrum (LDF), blue (LDB, peak at 450 nm), orange (LDO, peak at 595 nm) and red (LDR, peak at 629 nm) from the embryo stage to 60 days post hatching (dph). During this time, the growth and immune response of the turbot were evaluated. Whole fish tissue samples were collected and weighed. mRNA expression levels of insulin-like growth factor-I (IGF-I), heat shock protein 70 (HSP70), glutathione S-transferase (GST), catalase (CAT), metallothionein (MT), lysozyme (LZM), cathepsin D (CTSD), cathepsin F (CTSF) and the enzyme activity of superoxide dismutase (SOD), CAT, and peroxidase (POD) were measured at 10, 20, 30, 40, 50, and 60 dph. The results showed that LDB had a positive effect on the growth of turbot larvae at 20, 40, 50 and 60 dph, while this effect was not significant at 10 and 30 dph. Levels of IGF-I mRNA also showed a similar tendency, indicating the crucial interaction between IGF-I and somatic growth. The effect of light spectrum on the stress response of turbot larvae was stage specific. At 10 dph, prior to metamorphosis, long wavelengths could induce a stress response in turbot larvae. At 20 dph, metamorphosis began and no significant stress response was observed in larvae exposed to different light spectra; however, LDO significantly up-regulated SOD, CAT, POD and LZM activity. Metamorphosis continued until 56 dph. From 20 to 60 dph long wavelengths (LDR and LDO) resulted in a stress response characterized by high mRNA expression levels of HSP70, GST, CAT, MT, LZM, CTSD and CTSF. SOD, CAT, POD and LZM activities were inhibited, indicating increased enzyme consumption to maintain homeostasis. Overall, our results suggested that LDF should be used in turbot culture systems prior to metamorphosis and LDB should be used after metamorphosis. These findings are in keeping with the changes in light spectra experienced by turbot larvae undergoing metamorphosis in the wild.
Light is a key environmental factor that synchronizes various life stages from embryo development to sexual maturation in fish. For turbot, light spectra have the most influence at the larval and juvenile stages. In the current study, differences in the development of embryos and the performance of newly hatched turbot larvae exposed to five different spectra: full spectrum (LDF), blue (LDB, peak at 450 nm), green (LDG, peak at 533 nm), orange (LDO, peak at 595 nm)and red (LDR, peak at 629 nm), were examined. At 62.8 h post fertilization, a higher number of embryos exposed to short-wavelengths (LDG and LDB)had developed a heartbeat in comparison with embryos exposed to other wavelengths. Larvae exposed to the green spectrum had higher malformation rates than larvae exposed to the other spectra, indicating that larvae exposed to green light may have significantly reduced survival rates. The results of non-specific immunity parameters showed that the mRNA expression levels of cathepsin D (CTSD), cathepsin F (CTSF), catalase (CAT)and metallothionein (MT)in larvae exposed to LDB were significantly higher than those exposed to other spectra, but CAT activity in larvae exposed to LDB was significantly lower than larvae exposed to the other spectra. There was no significant difference in MT activity in larvae exposed to the five different spectra. The mRNA expression level of lysozyme (LZM)in larvae exposed to LDR was significantly higher than other spectra, while there was no significant difference in LZM activity observed in larvae exposed to LDR, LDG, LDB and LDF. The difference of the enzyme activity of total superoxide dismutase (T-SOD)was not significant among larvae exposed to the five spectra. mRNA expression of the heat shock protein 70 (HSP70)was significantly higher in newly hatched larvae exposed to LDB, LDR and LDG, indicating that larvae exposed to LDB, LDG and LDR exhibited a stress response. The mRNA expression level of the insulin-like growth factor-1 (IGF-1)and growth parameters in the newly hatched larvae exposed to the different spectra were not significantly different. The results of the present study indicate that LDO and LDF should be used for embryo incubation and newly hatched larvae when rearing turbot. This study provides a theoretical basis for optimizing the incubation light environment for fertilized turbot eggs, promoting immunity and reducing stress responses in newly hatched larvae.
The pineal gland is the main organ involved in the transduction process converting environmental light information into a melatonin response. Since light environment was described as an important factor that could affect physiology of teleosts, and because melatonin is a crucial hormone regulating numerous physiological processes, we hypothesized that environmental light may act on both stress and circadian axes which in turn could influence the immune status of pikeperch. Therefore, we investigated the effects of two light spectra (red and white) and two light intensities (10 and 100 lx) with a constant photoperiod 12L(8:00‐20:00)/12D on pikeperch physiological and immune responses. Samples were collected at 04:00 and 16:00 at days 1 and 30 of the experiment. Stress markers, plasma melatonin levels, humoral innate immune markers and expression of key immune genes in the head‐kidney were assessed. Light intensity clearly affected pikeperch physiology. This included negative growth performances, increase in stress status, decrease in plasma melatonin levels, and immune depression. Light spectrum had only little influences. These results demonstrate that high stress status may have impacted melatonin production and secretion by the pineal organ. The drop in circulating melatonin and the increase in stress status may both be involved in the immune suppression.
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The effect of environmental factors such as water temperature, experimental conditions (fish in control), toxicants (heavy metals, herbicides, insecticides, etc.), and features of physiological state (starvation, early ontogenesis, reproduction, and relationship) on the activity and content of lysozyme in serum/plasma and some immune organs in fishes of the family Cyprinidae have been reviewed. Similar and multidirectional reactions of the enzyme under the influence of the same factors, as well as a wide range of variation, various units, and dimensions of the studied parameter of nonspecific resistance, have been shown. This review presents research materials that have been published in the past 15 years.
This study aimed to investigate the influence of illumination with different light spectra on growth and stress response in pearl gourami Trichopodus leerii Bleeker, 1852. Fish (6.35 ± 0.43 cm, 5.69 ± 0.67 g) were reared in 8 glass aquaria each with 25 fish under one of four different lighting conditions: yellow (max 546 nm), red (max 605 nm), blue (max 470 nm) and white (control). Experiments lasted for 90 days. The stress response was evaluated by measuring cortisol levels. No significant effect was observed on final body weight, length and specific growth rate of fish. However, best values for these characteristics were achieved for fish reared under yellow light. A significant higher weight gain, condition factor was found in fish reared under yellow light compared with fish reared under blue or red light. In contrast, a lower final body weight, specific growth rate and weight gain were achieved for fish reared under red light. Feed conversion ratio was significantly lower in fish under yellow light compared with red or blue light. Stressed fish showed lower cortisol levels under yellow light compared with other light exposures. The study indicates that, pearl gourami grows better under yellow light and that yellow light lowers the stress-induced cortisol response.
To investigate the effects of niacin on growth, digestion and absorption capacity, and the potential mechanism for digestive and brush border enzyme activities, grass carp (Ctenopharyngodon idella) (256 ± 0.41 g) were fed diets containing 3.95 (basal diet group), 14.92, 24.98, 35.03, 44.97 and 55.01 mg niacin kg−1 diet for 8 weeks. Results indicated that percentage weight gain (PWG), feed intake and feed efficiency were the lowest in basal group (P < 0.05). Similarly, niacin deficiency decreased hepatopancreas trypsin, chymotrypsin, lipase and amylase activities (P < 0.05), intestinal Na+, K+-ATPase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase (CK) activities, the cholecystokinin (CCK) content in proximal intestine (PI) and growth hormone content in serum (P < 0.05). Furthermore, niacin deficiency downregulated gene expression of hepatopancreas trypsinogen 1, trypsinogen 2, chymotrypsinogen and amylase, intestinal Na+, K+-ATPase alpha subunit isoform 1, Na+, K+-ATPase alpha subunit isoform 8 and CK, and target of rapamycin (TOR) and S6 kinase 1 (S6K1) of hepatopancreas and intestine (P < 0.05), whereas upregulated eIF4E-binding protein (4EBP) gene expression (P < 0.05). The niacin requirement for young grass carp (256–689 g) based on PWG, hepatopancreas trypsin activity and Na+, K+-ATPase in PI was 34.01, 35.10 and 42.08 mg kg−1 diet, respectively.
Three basal diets containing 0, 27.5, and 55% solvent-extracted cottonseed meal (CSM) as replacements of 0, 50, and 100% of solvent-extracted soybean meal (SBM) on an equal nitrogen basis were each supplemented with three levels (40, 336, and 671 mg) of iron (Fe) from ferrous sulfate heptahydrate (3×3 factorial experiment). Each diet was fed to juvenile channel catfish, Ictalurus punctatus in triplicate aquaria twice daily to apparent satiation for 10 weeks. Dietary levels of CSM significantly affected weight gain (WG), feed intake (FI), feed efficiency ratio (FER), protein efficiency ratio (PER), and apparent protein utilization (APU), with diet containing 27.5% CSM provided the best performance. Total replacement of SBM by CSM decreased weight gain and feed consumption, possibly due to toxic effect of free gossypol. Supplementation of dietary iron from iron sulfate heptahydrate at a 1:1 weight ratio of iron to free gossypol had no effect on gossypol toxicity. Histological examinations of fish fed CSM containing (27.5% and 55%) diets had increased glycogen accumulation in liver as compared to that of fish fed the SBM-based diets. Fish fed 55% CSM and 0% SBM-based diets had increased liver necrosis and liver and anterior kidney pigment deposition. These parameters were not evident in fish fed diets containing 27.5% CSM. Dietary levels of iron and interactions between CSM and iron had no effect on the liver, spleen, or anterior head kidney histology. WG, FI, PER, and APU were significantly affected by the interaction between dietary levels of CSM and Fe. For SBM-based diets, these parameters linearly increased with increasing dietary level of iron. This effect was not observed for diets in which 50 and 100% of SBM were replaced by 27.5 and 55% CSM. Survival, and serum and liver iron content were not affected by dietary levels of CSM, iron, or their interaction. The effect of CSM on whole body composition was seen only for fish fed the 55% CSM diets, with fish fed these diets having lowest fat and highest moisture content. Dietary level of iron and the interaction between iron and CSM had no effect on whole body composition.
The effect of lighting spectrum (full vs. blue) on skin colour and stress response in red porgy, Pagrus pagrus, held under a 12L:12D photoperiod was investigated. Fish exposed to blue lighting spectrum became gradually paler with a
maximum lightness value (L = 45.33) on day 27, significantly higher than control fish (L = 31.49). However, there was no difference
in skin melanin content, hue and chroma among the experimental groups. There was also no statistically significant effect
of lighting spectrum on average glucose, thyroxine (T4), triiodothyronine (T3), cortisol (F) and Melanophore Stimulating Hormone (MSH) plasma concentrations nor in the pattern of changes during the time
course of the experiment. Results showed that lighting spectrum affects skin lightness but not the chromaticity attributes
hue and chroma. This effect is due to changes in the motility of the melanophores (the area occupied by melanosomes) and is
not mediated by MSH or the general stress response.
The main aim of our experiments was to study the influence of colored light on juveniles of Carassius carassius, Perccottus glenii and Poecilia reticulata. The species of fish used for studies differ in their biotopes and feeding behavior. The results of experiments demonstrated that different species of fish can have different response to light quality. Thus crucian carp developed better by green light, rotan-by blue and green, guppy - by blue light. By red light the growth rate in all species decreased. The response in different species of fish to the light environment appears to be governed by changes in energy metabolism and hormone disproportionation.
This study was conducted to evaluate the effects of diets including 0, 5, 10, 15, 25, and 40% alfalfa meals (containing 0, 20, 40, 60, 100, and 160 mg total carotenoids/kg diet, respectively) and 60 mg apo-ester, a synthetic carotenoid/kg diet on skin pigmentation, growth, feed utilization and survival of a red variety of goldfish, Carassius auratus, with average initial weight of 10.3 g, for a rearing period of 60 days. The pigmentation degree in skin of goldfish increased significantly with increasing inclusion of alfalfa up to 25% level in the diet (P < 0.05). However, the alfalfa inclusion over that level did not lead to more total carotenoid accumulation in the skin of fish. The diets including apo-ester and 15% alfalfa, both of which contained 60 mg carotenoid/kg diet, had similar effects on total carotenoid deposition in the skin of fish. Alfalfa addition of 25% or higher in the diet had an adverse effect on growth of fish compared to the control group (P < 0.05). A similar phenomenon was observed in feed conversion ratio but at the 40% alfalfa inclusion level (P < 0.05). However, no significant difference was observed in the survival of the fish. The present results demonstrate that alfalfa can be successfully used as an alternative natural carotenoid source to the synthetic apo-ester in goldfish diets. Our data indicates that 15% is a suitable dietary level of alfalfa to ensure good pigmentation, acceptable growth and feed utilization in goldfish.
Red porgy, Pagrus pagrus, is a potential candidate for aquaculture. However, darkening of the body occurs after capture of wild fish and during farming of cultured animals. In fish, skin pigmentation is hormonally controlled and the main hormone involved in skin darkening, α-melanocyte-stimulating hormone (αMSH), is not only involved in pigmentation but also in the regulation of the response to stressors. In this study, several environmental conditions were evaluated for their potency to influence the skin colour and to evoke a stress response. Background colour was the main factor in controlling skin pigmentation. A light background colour restored the lightness value of the skin up to levels found in wild red porgy (L*=∼70). The background effect was enhanced by applying blue illumination. Light intensity had no clear effect on the body colour, but a high density of fish had a negative effect on the lightness. Plasma parameters (cortisol, αMSH, glucose, lactate and osmolality) were not influenced by background colour. A stocking density of 25 kg/m3 did not evoke a stress response in contrast to earlier studies on red porgy, nor influenced the body colour. We propose that this difference can be attributed to the number of fish per volume of water, which was lower than in other studies. This indicates that the number of fish per volume of water rather than the density in kilograms of fish per volume of water is the relevant factor. Furthermore, we suggest that the culture of adult red porgy can be optimised by maintenance of fish on a light background, thereby restoring the body colour to a more natural hue, without affecting the stress response.
In stressed tilapia, Oreochromis mossambicus, total alpha-melanocyte-stimulating hormone (alpha-MSH) levels and di-acetyl alpha-MSH/mono-acetyl alpha-MSH (di:mono) ratios are elevated. We therefore investigated the role of alpha-MSH in the regulation of the pituitary-interrenal axis. The corticotrophic activities of des-acetyl alpha-MSH, mono-acetyl alpha-MSH and di-acetyl alpha-MSH were compared. These forms of alpha-MSH were isolated from neurointermediate lobes and tested in a superfusion experiment with homologous interrenal tissue. The corticotrophic activity of di-acetyl alpha-MSH was the highest, followed by that of des-acetyl alpha-MSH and mono-acetyl alpha-MSH. Apparently, acetylation of alpha-MSH is of functional significance for corticotrophic action. Di-acetyl alpha-MSH proved to be about 100 times less potent than ACTH(1-39): the half-maximal stimulating concentrations for ACTH and di-acetyl alpha-MSH were 0.89 nmol/l and 110 nmol/l respectively. Surprisingly, a superfusate from neurointermediate lobes proved to be only about three times less active than a superfusate from the pituitary pars distalis, in which the corticotrophic activity is attributable to its ACTH content. When selectively stripped of all forms of alpha-MSH by passage through a Sepharose column coated with an antiserum against alpha-MSH, the neuro-intermediate lobe superfusate was devoid of corticotrophic activity. Thus alpha-MSH appears to be the corticotrophic factor in the superfusate of the neurointermediate lobe. After the same treatment, the corticotrophic activity of the pars distalis superfusate was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)
A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls.
A feeding trial was conducted for 60 days to delineate the effect of dietary carbohydrate on the haematology, respiratory burst activity and histology in Labeo rohita juveniles. One hundred and forty four fish (av. wt. 10+/-0.15 g) were randomly distributed into 12 treatment groups with each of two replicates. Twelve semi-purified diets with either 35% or 28% of crude protein were prepared with different amylase concentrations (0, 50, 100 and 150 mgkg(-1)) and starch type (gelatinised, G/non-gelatinised, NG) designated as T1 (NG, 35% CP, 0 mgkg(-1) amylase), T2 (G, 35% CP, 0 mgkg(-1) amylase), T3 (NG, 28% CP, 50 mgkg(-1) amylase), T4 (NG, 35% CP, 50 mgkg(-1) amylase), T5 (G, 28% CP, 50 mgkg(-1) amylase), T6 (G, 35% CP, 50 mgkg(-1) amylase), T7 (NG, 28% CP, 100 mgkg(-1) amylase), T8 (NG, 35% CP, 100 mgkg(-1) amylase), T9 (G, 28% CP, 100 mgkg(-1) amylase), T10 (G, 35% CP, 100 mgkg(-1) amylase), T11 (NG, 28% CP, 150 mgkg(-1) amylase) and T12 (NG, 35% CP, 150 mgkg(-1) amylase). The fish were acclimatised to the experimental conditions for 15 days during which time the control diet was fed. The blood haemoglobin percentage and RBC count was not significantly different (P>0.05) among the various treatments. Highest WBC count, total plasma protein, serum globulin and respiratory burst activity was found at 50 mgkg(-1) dietary amylase supplementation, whereas no variation (P>0.05) was found at 0, 100 and 150 mgkg(-1) dietary amylase supplementation. There was no difference (P>0.05) in the serum albumin and AG ratio among the experimental groups. Feeding either gelatinised or non-gelatinised carbohydrate did not affect the histological structure of the liver, kidney and intestine except in the T4 and T7 groups. The T4 group showed hyperplasia of the intestine and moderate vacuolation in hepatic cells, whereas the T7 group showed hyperplasia of the intestine. Non-gelatinised carbohydrates (46%) along with supplementation with 50 mgkg(-1) amylase stimulated the immune system in L. rohita juveniles. But supplementation of amylase to the gelatinised carbohydrate had no immunostimulating effect.
Abstract The influence of tank wall color and up-welling water flow on growth and survival of Eurasian perch larvae (Perca fluviatilis) was tested in an intensive culture system. Newly hatched larvae were fed Artemia nauplii, later combined with dry feed, and reared for 5 wk in either black tanks with up-welling water flow or in gray tanks with or without up-welling water flow. The perch larvae grew significantly faster in black tanks than in gray tanks regardless of water flow. Two weeks after hatching, a significantly higher mean weight was shown in larvae reared in black tanks compared to larvae reared in gray tanks with up-welling water flow, and after 4 wk, the mean weight was significantly higher than in both of the other treatments. The difference in growth was further enhanced during the last week of the experiment, and the final mean weights were 51.1 ± 1.9 mg in black tanks with up-welling water flow, 23.8 ± 2.1 mg in gray tanks with up-welling water flow, and 23.7 ± 2.2 mg in gray tanks without up-welling water flow. The cumulative mortality at the end of the experiment averaged 75% in all treatment groups. Taken together, the enhanced growth of Eurasian perch larvae in black tanks could be explained by high prey contrast and increased prey consumption. Up-welling water flow had no impact on growth and survival of the perch larvae in gray tanks, indicating that the availability and consumption of the prey were independent of water movement.
The optimal dosage of astaxanthin for goldfish Carassius auratus was determined by feeding a series of diets containing 0, 25, 50, 75, and 100 mg of astaxanthin/kg of diet for 4 wk. The pigmentation on fish skin was measured by visual assessment against a color chart and by counting chromatophores produced in the dermis layer of fish skin. Both criteria showed that 36–37 mg/kg astaxanthin was the optimal dosage to stimulate fish color. A 4-wk observation after this experiment demonstrated that fish color stimulated by dietary astaxanthin was stable in its intensity. Therefore feeding astaxanthin could be a suitable way for goldfish producers to stimulate color among fish grown in an algae-free environment. The survival rate of fish fed diets with astaxanthin was significantly higher than fish fed diets without astaxanthin. However, there was no significant effect of astaxanthin on fish weight gain.
Abstract The potential of using rendered animal protein ingredients, poultry by-products meal (PBM), meat and bone meal (MBM), and feather meal (FM), to replace fish meal in diets for malabar grouper, Epinephelus malabaricus, was evaluated in a 10-week net pen experiment. Triplicate groups of fish (initial body weight 50.2 g) were fed eight isonitrogenous and isocaloric diets formulated to contain 52% crude protein and 9% crude lipid. The control diet contained 50% herring meal, whereas in the remaining seven diets, PBM was incorporated at 11.9 (PM1), 23.8 (PM2), and 35.7% (PM3) to replace 25, 50, and 75% of the fish meal; MBM was incorporated at 14.5 (MM1) and 29.0% (MM2) to replace 25 and 50% of the fish meal; and FM was incorporated at 9.4 (FM1) and 18.8% (FM2) to replace 25 and 50% of the fish meal. A raw fish (RF) diet was used as comparison to assess growth performance of fish fed the formulated diets. Feed intake was lower in fish fed the diets PM3 and FM2 than fish fed the control diet. There were no significant differences in weight gain (WG), final body weight (FBW), nitrogen retention efficiency (NRE), energy retention efficiency (ERE), and total nitrogen waste output (TNW) between fish fed the control diet and the diets PM1, PM2, PM3, MM1, MM2, and FM1. Fish fed the diet FM2 had lower WG, FBW, NRE, and ERE but higher TNW than that of fish fed the control diet. Feed conversion ratio (FCR) was higher in fish fed the diets MM2, FM1, and FM2 than fish fed the control diet. At the end of the experiment, there were no significant differences in whole-body content of moisture, crude protein, and crude lipid among fish fed the formulated diets. WG, FBW, and TNW of fish fed the diet RF were higher, while FCR and NRE were lower than that of fish fed the control diet. No significant differences were found in feed intake, ERE, and whole-body composition between fish fed the diet RF and the control diet. Results of the present study suggest that dietary fish meal level for malabar grouper can be lowered from 50 to 38% by incorporating PBM, MBM, or FM.
Colour preference of individual juvenile rainbow trout Oncorhynchus mykiss was tested at 1 and 12° C, and also at 12° C after a 42 day growth experiment under white, blue, green, yellow or red ambient colour. All experiments were carried out under controlled laboratory conditions and the preference was assessed by the location of the fish in a preference tank with four chambers. Rainbow trout showed a preference for blue and green at 1° C and for green at 12° C. After the growth experiment the fish reared in blue tanks preferred blue and green but green was the most preferred colour for the fish reared in green, yellow and red tanks. Yellow and especially red chambers were avoided, irrespective of the ambient colour during the growth trial. The final mass of fish reared in the red aquaria was significantly smaller than that of the fish in green tanks. In addition, when the data of the preference tests were correlated with the data of the growth experiment using mean values of the four tested colours, a very good linear relationship was observed between the preference (i.e. visit frequency in coloured compartments) and growth rate as well as food intake. When considering the results both from the preference and growth trials it is suggested that green is the best environmental colour for rearing juvenile rainbow trout while rearing in a red environment cannot be recommended.
The majority of aquaculture farms in South Korea currently use a moist pellet (MP) based on a mixture of frozen fish and fishmeal as a feed source for marine-culture fish species. MP has been associated with several problems, including the deterioration of water quality and fish diseases on fish farms, owing primarily to the rapid collapse of MP in seawater. In order to circumvent those problems, we have developed a chitosan-based biopolymer coating material for the environment-friendly use of MP on aquaculture farms. The chitosan-coated MP diet was shown to improve water quality as compared to the non-coated MP diet in the fish farm environment. It resulted in reduced COD (chemical oxygen demand) and SS (suspended solid) values, as compared to the control. The fish fed with the chitosan-coated MP diet for 12 weeks manifested no significant differences in final body weight. However, some immune responses, including myeloperoxidase (MPO), neutrophil respiratory burst, and skin mucus lysozyme activity were significantly (p0.05). In addition, the fish fed with chitosan-coated diets evidenced significant (p
Jundiá (Rhamdia quelen) is a Heptapteridae fish native of South America, commonly found in rivers, and intensively cultured in artificial ponds. A feasible sequence for jundiá culture consists of hatchery, nursery, and termination. Before dispatch to fish farms, fingerlings are transferred from nursery tanks to indoor tanks for a waiting period of approximately 10 days. This “dispatch period” can be highly stressful because of dietary changes, maintenance at high densities, daily handling, and a noisy and disturbing environment. Four experiments were performed to determine whether color background and shelter availability influences the cortisol response to stress in Rhamdia quelen fingerlings. The first and second experiments tested the influence of color background on the acute cortisol response with or without shelter. In the third and fourth experiments, the time course of cortisol levels after stress was measured in fingerlings kept in tanks with white or blue backgrounds, with or without shelter. The results clearly demonstrated that the adaptation period of 10 days in white and blue tanks had no effect on the cortisol response to an acute stressor. However, the tank color combined with the presence of an appropriate shelter both reduce the magnitude and duration of the stress response evaluated in terms of cortisol concentrations. Taken together, the results suggest that, because a totally dark environment is not feasible in jundiá hatcheries, the best alternative to maintain R. quelen fingerlings are tanks with blue walls provided with shelter. These results may have strong applications in fish welfare and health during the transfer period of jundiá fingerlings and on its survival rate in the early periods in fish farms.
Eurasian perch (Perca fluviatilis) is receiving increasing attention as a new species in freshwater aquaculture. Understanding perch behaviour and performance in culture is important to optimize the design and management of tanks, and other culture conditions. The objective of this study was to evaluate how different combinations of tank colour and light intensity affect the feed intake, growth and energy expenditure of juvenile perch. Feed intake, growth rate and energetic growth efficiency were measured using groups of perch exposed to different combinations of tank colour (white, grey or black) and light intensity (200 or 1100 lx). Six groups of six perch were exposed to each colour/light combination. The initial average weight (±SD) of the fish over all experimental rounds was 59.6 g (±6.6). Perch in white and grey tanks ate more than the perch in black tanks (P
Metal halide lights are currently used as standard in commercial Atlantic salmon sea cages as a means of enhancing productivity through grilse inhibition. However, such systems create bright point light sources that are neither environment specific nor species specific and could potentially compromise fish welfare. Light emitting diodes (LEDs) are a new form of lighting technology currently being developed for the fish farming industry that can be tuned to environment and species sensitivities through narrow bandwidth outputs. However, prior to implementing these new high energy alternatives, any potential adverse effects must be determined in fish. The objectives of this study were thus (1) to determine the effect of increasing intensities of blue LED light (0.199–2.7 W m−2, at 0.1 m from the light source) on light perception and stress response, and (2) to examine potential retinal damage under these conditions in post-smolt Atlantic salmon, Salmo salar. A white LED light was also tested, as well as a very high intensity metal halide positive control. Results demonstrated firstly that salmon perceived blue LED light (basal melatonin levels maintained) irrespective of intensity. Secondly, fish exposed to high intensity blue LED light showed an increase in plasma cortisol and glucose levels within 3 h, returning to a basal state 24 h post-light onset. This typical acute stress response was not observed in fish exposed to the white LED light and lower blue light intensities which could indicate differential sensitivities to spectral content of the light. No effects on the non-specific immune system (lysozyme activity) were observed. Finally, extensive histological examination of the retina from fish exposed to these various light treatments revealed no signs of damage. This demonstrates the efficiency of the adaptive mechanisms to light developed in fish.
In stressed tilapia, Oreochromis mossambicus , total α-melanocyte-stimulating hormone (α-MSH) levels and di-acetyl α-MSH/mono-acetyl α-MSH (di:mono) ratios are elevated. We therefore investigated the role of α-MSH in the regulation of the pituitary–interrenal axis. The corticotrophic activities of des-acetyl α-MSH, mono-acetyl α-MSH and di-acetyl α-MSH were compared. These forms of α-MSH were isolated from neurointermediate lobes and tested in a superfusion experiment with homologous interrenal tissue. The corticotrophic activity of di-acetyl α-MSH was the highest, followed by that of des-acetyl α-MSH and mono-acetyl α-MSH. Apparently, acetylation of α-MSH is of functional significance for corticotrophic action. Di-acetyl α-MSH proved to be about 100 times less potent than ACTH(1–39): the half-maximal stimulating concentrations for ACTH and di-acetyl α-MSH were 0·89 nmol/l and 110 nmol/l respectively. Surprisingly, a superfusate from neurointermediate lobes proved to be only about three times less active than a superfusate from the pituitary pars distalis, in which the corticotrophic activity is attributable to its ACTH content. When selectively stripped of all forms of α-MSH by passage through a Sepharose column coated with an antiserum against α-MSH the neurointermediate lobe superfusate was devoid of corticotrophic activity. Thus α-MSH appears to be the corticotrophic factor in the superfusate of the neurointermediate lobe. After the same treatment, the corticotrophic activity of the pars distalis superfusate was not affected. We conclude that ( in vivo ) an as yet unidentified factor is co-released with α-MSH from the neurointermediate lobe, and that this potentiates its corticotrophic activity.
Journal of Endocrinology (1992) 135, 285–292
The aim of the present study was to evaluate the possible anti-stressful effect of dietary tryptophan supplementation on growth of juvenile rainbow trout (Oncorhynchus mykiss) reared in different background colour using recirculating water system. Therefore, rainbow trout (4.7 g ± 0.02) were reared for 11 weeks in black, light blue and white tanks and fed either a commercial diet or the same diet supplemented with tryptophan (2 g 100 g–1 diet). Rearing in black tanks led to reduced final weight and total length, lower food consumption, food conversion ratio and body protein, while no differences were observed between fish reared in light blue or white tanks. Feeding the fish tryptophan supplemented diet resulted in depressed growth, increased food consumption and food conversion ratio, decreased body protein and increased body lipid, reduced liver total lipids and a marked increase in hepatosomatic index (least in fish reared in white tanks). It is concluded that rearing on a black background was stressful for rainbow trout juveniles, while the dietary level of tryptophan used failed as a stress releasing factor and probably evoked an amino acid imbalance.
Appropriate rearing conditions for successful farming of white sea bream Diplodus sargus L. have not yet been deeply studied, while one of the major problems is the species increased aggressiveness. Given the known effect of density and background colour on fish growth, welfare and social behaviour, the present study aimed to investigate whether the two factors combined could favor D. sargus performance. Juveniles (17.37 ± 0.06 g) were reared in white, light blue and black tanks under low (7 fish tank-1 or 1.96 kg m-3) and high (28 fish tank-1 or 7.79 kg m-3) density for 87 days. Water quality was not affected by experimental treatments. Best overall performance (growth, food utilization, body protein content, liver fatty acids) was achieved under low density and white or light blue tanks. Increased inciden