Effects of substitution of moist fermented feed for dry pellet feed on hepatopancreas and intestinal health, and intestinal microbiota homeostasis of Pacific white shrimp (Litopenaeus vannamei)

The present study evlatuated the effects of moist fermented feed (MFF) substituted for dry pellet feed on hepatopancreas and intestine health and intestinal microbiota of Pacific white shrimp ( Litopenaeus vannamei ). A total of 150 shrimp (1.56 ± 0.02 g) were fed with moist fermented feed once every two days (MFF0.5/4), once a day (MFF1/4), twice a day (MFF2/4) and four times a day (MFF4/4) or the control diet (dry pellet feed) for 8 weeks. MFF had no effect on the weight gain rate (WGR) of shrimp, but showed a notable lower survival rate (SR) and feed conversion ratio (FCR) in the MFF4/4 group ( P < 0.05). The levels of TAG and R-cells in the hepatopancreas of the MFF1/4 group were markedly lower ( P < 0.05). Additionally, the hepatopancreas level of T-AOC in MFF1/4 and the activity of SOD in MFF1/4 and MFF2/4 groups were significantly increased ( P < 0.05). The expressions of nf-kb and penaeidin-3a and crustin genes in the hepatopancreas of shrimp fed on MFF0.5/4 and MFF1/4 were notably upregulated ( P < 0.05). Relative to the control group, the expression of tgf-β in MFF1/4, Penaiedin-3a and Peritrophic in MFF0.5/4 and MFF1/4 groups were noteworthy upregulated in the intestine ( P < 0.05). Moreover, MFF0.5/4, MFF1/4 and MFF2/4 levels improved the intestinal microbiota of shrimp by decreasing the abundance of opportunistic pathogen Vibrio and Pseudomonas genus. In summary, feeding MFF once a day or once every two days improved the hepatopancreatic and intestinal health of shrimp, and feeding MFF once a day seems better for promoting the health of shrimp. • MFF could promote the health of hepatopancreas of shrimp by improving the composition of hepatopancreas cells. • MFF could improve intestinal health and optimize intestinal microbiota structure of shrimp. • Once every one or two days feeding with the moist fermented feed substituted to dry pellet feed seems more efficient and healthy for shrimp.