Substitution of feed protein as means of altering intestinal microbiome and growth of rainbow trout (Oncorhynchus mykiss). Protein substitution rainbow trout microbiota

The microbial community in the fish intestine are important for the digestion of feed and the secretion of health-promoting substances such as vitamins and fatty acids. The diet composition can impact the community structure and induce positive or negative effects on fish health. The present study aimed to evaluate the impact of various protein sources on growth and intestinal microbiota in rainbow trout (Oncorhynchus mykiss). Rainbow trout were reared for 68 days while being fed to satiation with one of eight experimental diets containing (fishmeal) with either krill, wheat, corn gluten, horse beans, squid, salmon, distillers’ grains or insects. Analysis of the intestinal microbiome showed that the change in protein source specifically altered the composition of the gut microbiota. The obtained results suggest that small feed substitutions can be used to modify the gut microbiome and thereby contribute to the development of pathogen-free fish as well as promote a gut flora with probiotic effects in order to support fish health and welfare without affecting growth.