Effect of dietary n-3 HUFA on growth performance and tissue fatty acid composition of gibel carp Carassius auratus gibelio

Abstract

A 12-week growth trial was conducted with gibel carp Carassius auratus gibelio (initial weight: 2.69 g) to evaluate the effects of dietary n-3 highly unsaturated fatty acids (n-3 HUFA) on growth performance and tissue fatty acid composition. Five diets of different n-3 HUFA levels from 0 to 17 g kg(-1) diet were supplemented at 80 g kg(-1) dietary lipid by including fish oil (FO) at 0, 25, 50, 75 and 100% of supplemental lipid. The remainder was coconut oil. The results showed that fish fed FO25 and FO50 obtained highest specific growth rate and lowest with FO0. Feed efficiency was highest at FO100 and lowest at FO0. Apparent digestibility coefficient of lipid increased with increasing dietary n-3 HUFA. The fish fed FO0 diet had the lowest thiobarbituric acid reactive substance in serum and muscle and highest moisture and lowest lipid content in viscera. Fatty acid compositions of muscle and liver were correlated with dietary fatty acids. Fish muscle concentration of 20:5n-3 increased with increasing dietary n-3 HUFA while the concentration of 22:6n-3 was distinctly reduced in FO0 group. It suggested that 4 g kg(-1) n-3 HUFA in diet could permit gibel carp normal growth performance and provide considerable n-3 HUFA in fish muscle. Excessive n-3 HUFA showed impact on growth performance of gibel carp.