Effects of dietary Bacillus cereus supplementation on the growth performance, serum physiology and biochemistry, Nrf2, TLR/NF-κB signaling pathways, and intestinal health of juvenile coho salmon (Oncorhynchus kisutch)

Abstract

This study aimed to investigate the effects of dietary Bacillus cereus supplementation on the growth performance, serum biochemistry, intestinal health, and Nrf2 and TLR/NF-κB signaling pathways of juvenile coho salmon (Oncorhynchus kisutch). Four different concentrations of B. cereus in the feed were prepared: 0 (control group), 2×107 CFU/g, 4×109 CFU/g, and 8×1011 CFU/g. Each group had three replicates, and each replicate was fed 20 juvenile coho salmon (initial body weight = 128.78 ± 5.75 g) for 10 weeks. Results showed that the addition of B. cereus to the weight gain rate, specific growth rate, feed conversion ratio, protein efficiency ratio, crude protein, and expression of nuclear factor erythroid 2-related factor 2, kelch-like ECH-associated protein 1B, glutathione peroxidase, glutathione S-transferase, glutathione-disulfide reductase, superoxide dismutase, catalase, toll like receptor 3 (TLR3), TLR7, heat shock protein family A member 8 (Hsp70), lysozyme, complement C3, nuclear factor NF-kappa-B, tumor necrosis factor, transforming growth factor beta, interferon gamma, interleukin-1 beta, interleukin-6, and interleukin-8 genes, as well as serum physiological and biochemical and liver antioxidant enzyme activity indicators, were significantly affected (P 0.05). In conclusion, the addition of B. cereus at a concentration of 4×109 CFU/g to diets can effectively promote the growth of juvenile coho salmon, enhance antioxidant and immune capabilities, and improve intestinal health.

Keywords

• Coho salmon
• Bacillus cereus
• Growth performance
• Signaling pathway
• Intestinal health