Effects of dietary shrimp extract on growth performance, muscle fatty acid composition, and lipid metabolism‐related genes of juvenile red tilapia

Abstract

AbstractShrimp extract (ShE) is one kind of aquatic animal attractant with abundant amino acids. In order to investigate the effects of dietary ShE supplementation on the growth and muscle fatty acid of juvenile red tilapia (initial weight: 12.02 ± 0.02 g), a 62‐day experiment was conducted. The fish were fed six diets containing graded levels of ShE (0%, 0.5%, 1%, 2%, and 3%) without fish meal (FM) and an FM diet in triplicate groups. At the end of the experiment, the final body weight, weight gain, specific growth rate, and feed intake of the red tilapia fed the 3% ShE diet and FM diet were significantly higher than those fed the other diets (p < .05). The total saturated fatty acid of fish muscle in the ShE diet groups was lower than that in the FM diet group (p < .05). The contents of erucic acid (C22:1), eicosapentaenoic acid (C20:5 n‐3; EPA), docosapentanoic acid (C22:5 n‐3; DPA), and docosahexaenoic acid (C22:6 n‐3; DHA) in the ShE diet groups were also lower than those in the FM diet group (p < .05). The expression level of the lpl gene in red tilapia liver of experimental group was significantly higher than that of the control group (p < .05). The liver mdh gene mRNA expression levels were higher in the red tilapia fed 0.5%, 2%, and 3% ShE diets than those of other groups (p < .05). Moreover, the respiratory burst activity had a positive effect in the 0.5%, 1%, and 2% ShE diet groups (p < .05). Our results suggest that dietary ShE has a significant effect on the growth and lipid metabolism‐related genes of fish, and 3% ShE was recommended to be supplemented in juvenile red tilapia diets.