Interaction of fish density and background color effects on growth performance, proximate body composition and skin color of common carp, Cyprinus carpio

摘要

This study was carried out to evaluate the combined effects of three stocking densities and two tank colors on growth, body composition and skin coloration of common carp (1.41±0.05 g). Fish with low (LD: 20 specimens/tank or 0.70 g/L), medium (MD: 40 specimens/tank or 1.41 g/L) and high (HD: 80 specimens/tank or 2.82 g/L) densities were reared in two tank colors (black and white) for 45 days. At the end of the experiment, density recorded 2.45 g/L and 7.00 g/L at low and high densities treatments, respectively. The final weight and specific growth rate of the fish at LD treatment were significantly higher than those of MD and HD treatments. The highest weight (4.90±0.44 g) and the lowest feed conversion ratio (1.21±0.13) were obtained for the LD fish treatment reared in the black tanks. Rearing density has a significant effect on the fish body total protein content, but the tank color had no effects on this factor. The fish body lipid content in the white tanks and high density was significantly higher than other treatments. Significant interactions between tank color and rearing density were observed for the fish body protein, fiber and dry matter. The fish skin color was considered by three factors: L*, a* and b*. The results showed that black color had a negative effect on the fish skin color indices. Brightness (L*) and yellowness (b*) values of the fish skin in the white tanks were higher than those of the black tanks. In the present study, tank color and rearing density significantly affected growth and feed performance of common carp, while no combined interaction was found between the two factors examined.