Fish meal-free diet supplemented with health promoters support optimal growth in gilthead sea bream (Sparus aurata), with beneficial changes in gene expression, intestinal microbiota and intestinal disease recovery

Here, we tested a novel aquafeed formulation containing a gut health modulator, aquaculture by-products, black soldier meal and microbial biomass generated by fermentation of Corynebacterium glutamicum and Methylococcus capsulatus as the main protein sources in a FM-free diet. The effects on growth performance; targeted liver, head kidney and intestinal gene expression; intestinal microbiota composition; and parasite disease outcome were assessed to evaluate the potential use of this novel and sustainable feed formulation in aquaculture. At the gut level, main attention was focused on the posterior intestine due to its relevance as the main target tissue for the economically important intestinal parasite Enteromyxum leei, used for the challenging of fish in an infective model of cohabitation.