Partial replacement of soybean meal with fermented cottonseed meal in a low fishmeal diet improves the growth, digestion and intestinal microbiota of juvenile white shrimp Litopenaeus vannamei

Abstract

This study investigates the effects of replacing soybean meal with fermented cottonseed meal (FCSM) in low fishmeal diets on the growth performance, antioxidant capacity, immune capacity, digestive enzyme activities and intestinal microbiota of Litopenaeus vannamei. Six isonitrogenous and isolipidic diets were prepared, including the conventional fishmeal (250 g kg−1) group as the control, and the low fishmeal (150 g kg−1) diet used FCSM (0, 105, 210, 315 and 420 g kg−1) to replace 0 % (FCSM0), 25 % (FCSM25), 50 % (FCSM50), 75 % (FCSM75) and 100 % (FCSM100) soybean meal of the diet. Each diet was fed to four replicate groups of shrimp (0.16 ± 0.01 g) for 8 weeks. The results showed that the survival of the FCSM0 group was significantly lower than that of the other groups (P < 0.05). The weight gain and specific growth rate of the FCSM0 group were significantly lower than those of the control and FCSM75 groups (P < 0.05). The crude protein of whole shrimp was significantly decreased in the FCSM75 group compared with the control and FCSM100 groups (P < 0.05). The contents of essential amino acids, nonessential amino acids and total amino acids of L. vannamei in the FCSM25, FCSM50, and FCSM75 groups were significantly higher than those of the control (P < 0.01). The intestinal microbiota sequencing results showed that FCSM increased the microbiota diversity. At the genus level, the FCSM75 group had a lower abundance of Vibrio, Demequina, Microbacterium, Photobacterium and Roseburia than the FCSM0 group. Based on the KEGG functional prediction results, compared with the FCSM0 group, the FCSM75 group significantly upregulated the “glutathione metabolism”, “galactose metabolism”, and “amine and polyamine biosynthesis” pathways in the intestinal microbiota. This study demonstrates that replacing 75% soybean meal with FCSM in a low fishmeal diet could improve the growth performance, antioxidant capacity, and essential amino acid content of L. vannamei.