Oligosaccharides improve the flesh quality and nutrition value of Nile tilapia fed with high carbohydrate diet.

High level of carbohydrate in aquafeed could achieve cost-sparing effect, but it may cause adverse effects on flesh quality of aquatic products. An eight-week trial was conducted to investigate whether oligosaccharides-supplementation, including Galacto-oligosaccharides (GOS) and xylo-oligosaccharide (XOS), could systematically improve the growth performance, texture characteristics and nutrition composition of Nile tilapia fed with high-carbohydrate diet. The results indicated that GOS-supplementation improved the amino acid composition, while XOS-supplementation showed beneficial effects on growth performance. High-carbohydrate diet had adverse effects on fillet texture, while oligosaccharide-supplementation regulated the expression of muscle development-related genes to help restoring muscle texture properties. Furthermore, either high-carbohydrate or addition of oligosaccharides could change the intestinal microbiota composition and their metabolites. Further correlation analysis suggested that intestinal microbiota may account for the improvement in fish growth condition and texture characteristics. Application of oligosaccharides may be an innovative strategy for flesh quality modulation in aquaculture.