Mucosal barrier status in Atlantic salmon fed marine or plant-based diets supplemented with probiotics

Feed ingredients and additives significantly affect the mucosal health of fish. A 3 × 2 factorial experiment was conducted to investigate Atlantic salmon (Salmo salar) fed three basal feeds (namely, BG1, BG5 BG2; marine-, plant-, soybean meal-based feeds, respectively) or with (+) without (÷) probiotics, Lactobacillus fermentum plantarum. Six diets were fish distributed into 12 tanks (approximately 43 fish/tank). The average start weight experimental about 122.6 g. After 38-days feeding, dorsal skin, gills distal intestine obtained for analysing histomorphometry mucus-related genes. Digesta also collected study short chain fatty acids (SCFAs). Fish BG2 had higher number mucous cells/?m2 skin epithelium (SNE) than those BG1 BG5. Addition probiotics increased SNE in BG5+ BG2+ group compared BG1÷ group. Similarly, area gill (GME GNE) group, followed by groups. Probiotics GME GNE all feed types. Concerning intestine, villi height (VH) enterocyte (EH) Compared offered BG2, wider (VW) narrower lamina propria (LPW). cells (NM) intraepithelial lymphocytes (IEL) BG1. indices VH, VW, EH, IEL not affected probiotics. Although NM observed BG2÷ other two diets, reduced IEL. showed symptoms inflammation, including disappearance supranuclear vacuoles (SNV). improved LPW aided reappearance SNV Some gene expression data supported histological findings; notably, levels muc5ac1 defensin3 cathelcidin1 correlated histology data. Moreover, total SCFA concentration ingredients. Only acetoacetic acid both factors. Our findings suggest that can alter protective barrier organs. Supplementation alleviated inflammatory responses activated selected innate immune defence molecules, affecting growth. positive effect similar regardless ingredients, suggesting these be utilized as regulators evoke favourable on intestine.