Effects of dietary xylooligosaccharide on growth, digestive enzymes activity, intestinal morphology, and the expression of inflammatory cytokines and tight junctions genes in triploid Oncorhynchus mykiss fed a low fishmeal diet

Abstract The purpose of this study was to show how dietary xylooligosaccharides (XOS) affect growth and intestinal digestive enzyme activity, histology, inflammatory cytokines, barrier function gene expression, and microbiota of juvenile rainbow trout (Oncorhynchus mykiss). Different diets (G1, G2, G3, G4, and G5) containing graded levels of XOS (0, 2.5, 5.0, 7.5, and 10.0 g/kg) were fed to triplicate groups of 30 fish (initial average weight 20.85 ± 0.48 g) for 56 days. The fish fed 10 g/kg XOS had significantly improved weight gain (P