Evaluation of Yeast Hydrolysate in a Low-Fishmeal Diet for Whiteleg Shrimp ().

An eight-week feeding trial was performed to evaluate the effects of yeast hydrolysate (YH) supplementation in a low-fishmeal diet on the growth, immune responses, intestinal histology and disease resistance of whiteleg shrimp (). Five experimental diets were produced by supplementing YH at 0 (CON), 0.5 (YH), 1 (YH), 2 (YH) and 4 (YH) % to a basal diet containing 10% fishmeal and compared with a positive control with 25% fishmeal (FM). Shrimp with an initial average weight of 0.43 ± 0.005 g (mean ± SD) were stocked in 18 tanks and fed the experimental diets (38% protein and 8% lipid) four times a day. Results showed that shrimp fed the FM diet exhibited significantly higher final body weight, weight gain, specific growth rate and protein efficiency ratio than those fed CON, YH, YH and YH diets ( < 0.05). However, there were no significant differences between shrimp fed the YH and FM diets ( > 0.05). In addition, there were no significant differences in whole-body proximate composition, hemolymph biochemical parameters and non-specific immune responses among treatments. Intestinal villi length and muscular layer thickness of shrimp fed the YH and FM diets were significantly higher than the other groups. At the end of the bacterial () challenge test, shrimp fed YH and FM diets showed a significantly higher survival rate than those of shrimp fed CON, YH and YH ( < 0.05). These results suggest that supplementing 4% YH in diet containing 10% fishmeal could beneficially influence growth, intestinal morphology and disease resistance of whiteleg shrimp.