Glutathione-rich yeast hydrolysate makes the contributions to growth performance, healthy of Pacific white shrimp (Litopenaeus vannamei), and helps shrimp resist nitrite stress

Abstract

Seven diets were formulated to investigate the effects of glutathione-rich yeast hydrolysate (GYH) on growth performance, antioxidant capacity, and innate immunity of Litopenaeus vannamei. Based on the control diet (28% fishmeal content, CON), six diets supplement with GYH 0% (G0), 0.3% (G0.3), 0.5% (G0.5), 0.7% (G0.7), 0.9% (G0.9) and 1.1% (G1.1) were prepared after cottonseed protein concentrate replacing fishmeal 28.5% of the CON. After the 8 weeks feeding experiment, the shrimp fed diet containing 0.5%− 0.9% GYH obtained better growth performance compared to the CON and G0 groups, as well as the significantly lower feed conversion rate (P < 0.05). The intestinal villus height of shrimp fed diet with 0.3–0.9% GYH was significantly higher than the G0 group (P < 0.05). Decreased serum malondialdehyde content and significantly increased total antioxidant capacity, reduced glutathione content, activity of glutathione peroxidase and phenoloxidase in the hepatopancreas were found in shrimp fed diet with 0.7–0.9% GYH (P < 0.05). In addition, supplement 0.5–0.9% GYH significantly upregulated the expression levels of genes igf-1, pi3k, akt, tor, s6k1, and 4ebp1 in muscle and increased the crude protein content of the whole shrimp (P < 0.05). The expression levels of genes lgbp, proPO and lzm in the hepatopancreas were significantly upregulated in shrimp fed 0.7% GYH supplement (P < 0.05). Serum CAT activity in the G0.9 group was significantly higher than that of the G0 group before and after nitrite stress (P < 0.05). The shrimp fed diet supplemented with 0.5–1.1% GYH exhibited better intestinal tissue structure compared to groups CON and G0 after nitrite stress. In conclusion, the optimum level of dietary GYH was 0.67% based on the analysis of the quadratic term fitting results of weight gain rate. The diets supplemented with appropriate GYH could contribute to the growth and health of shrimp.