Effects of partial replacement of fish meal with black soldier fly (Hermetia illucens) larvae meal on growth performance, lipid metabolism and hepatointestinal health of juvenile golden pompano (Trachinotus ovatus)

This experiment was conducted to investigate the effects of partial replacement of fish meal with black soldier fly larvae (BSFL) meal on growth performance, body and muscle nutrients, lipid metabolism, intestinal morphology and microbiota of juvenile golden pompano (Trachinotus ovatus). Three isolipidic (12.40 +/- 0.29%) and iso-proteinic (42.98 +/- 0.02%) experimental diets were formulated to feed golden pompano by replacing 0% (BSFL0), 25% (BSFL25) and 50% (BSFL50) of fish meal with BSFL meal. The experiment lasted for a total of 8 weeks. The results showed that compared with BSFL0, BSFL25 could significantly increase feed intake of golden pompano (P < 0.05). However, BSFL50 significantly reduced growth performance (P < 0.05). The hepatosomatic index, body and muscle crude fat in BSFL25 and BSFL50 decreased. BSFL25 could significantly reduce the activity of fatty acid synthase (FAS) and significantly enhance the activity of lipase (LPS) (P < 0.05). Both BSFL25 and BSFL50 could significantly reduce the number and volume of lipid droplets in the liver, but BSFL50 could damage the intestinal morphology and shorten the intestinal villi. Compared with BSFL0, the richness (Chao1, ACE, Sobs) and diversity (Shannon and Simpson) of intestinal microbiota in BSFL25 and BSFL50 were increased, and the abundance of Proteobacteria, Actinobacteria and Bacteroidetes was increased. In conclusion, the replacement of 25% fish meal in the feed by BSFL meal improved the food intake, lipid deposition in the liver, and intestinal microbiota balance of golden pompano, and had no harmful effects on growth and intestinal health. However, when the substitution level reached 50%, it would have a negative impact on growth and intestinal health.