Search

An 8-week feeding trial was conducted to investigate the effects of host-associated Bacillus megaterium R32 and stachyose on the intestinal mucosal defense system of turbot ( Scophthalmus maximus . L). Three isonitrogenous and isolipidic diets were formulated: control diet (C), control diet with 1.0 × 10 8  CFU/g B. megaterium R32 (RC), and 1.0 × 10 8  CFU/g B. megaterium R32 + 1.5% stachyose (RS) supplementation separately. The results showed that diets RS and RC significantly inhibited the expression of cell development and apoptosis-related genes ( β-catenin , CyclinD1 , BAX , Bid ); diets RS and RC significantly increased the expression of intestinal tight junction protein claudin-4 , while RS group significantly decreased the expression of myosin light chain kinase ; diets RS and RC significantly decreased the expression of proinflammatory factors ( IL-13 , IL-15 , IFN- γ ), diet RS also significantly decreased the expression of TNF-α and AP-1 , and increased the expression of TGF-β . 16s rRNA gene sequencing results showed that diets RS and RC significantly decreased the abundance of conditional pathogenic bacteria ( Corynebacterium , Desulfovibrio , Escherichia-Shigella ). Among them, the abundance of Bacillus in the RS group was the highest. It is concluded that the combination of stachyose and B. megaterium R32 had a more positive effect on intestinal cell development and barrier function and strengthened the intestinal mucosal defense system of turbot., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Yaoyao Kong et al.)