Effects of colored light and tank color on growth indices and some physiological parameters of juvenile beluga (Huso huso)

The influence of colored light and tank color was investigated on growth performance (body weight, growth rate, carcass composition, etc.) and physiological status (blood and plasma parameters) of beluga (Huso huso) juveniles. The study was conducted using 64 specimens for colored light treatments with initial weight 98.83 +/- 1.42 (mean +/- SE) g which were reared under white, red, green and blue light and using 80 specimens for tank color treatments with initial weight 98.50 +/- 1.24 (mean +/- SE) g which were reared in white, red, green, black and blue tanks, all for 12 weeks. Red light had a significantly negative impact on beluga growth performance (in contrast with blue light) accompanied with reduced liver total lipids and plasma albumin and elevated plasma cortisol, glucose, cholesterol and triglyceride (in contrast with the other treatments). No significant effects of tank color were detected on growth performance. Nevertheless, most of growth parameters suggested a positive impact of black tank. Although plasma glucose levels in white tank were significantly higher than the other tank colors, no significant effects of tank color were detected for the other physiological parameters. Therefore, based on the obtained results, blue light by establishing comfort in beluga juveniles spelled increased growth performance and had positive significant effect on physiological conditions. Moreover, taking into consideration the consistency of all growth parameters among beluga juveniles reared in black tanks, it is suggested that considerable results in regard to this treatment may be achieved if the rearing period prolongs.