Modulation of Gilthead Sea Bream Gut Microbiota by a Bioactive Egg White Hydrolysate: Interactions Between Bacteria and Host Lipid Metabolism

This study aimed to highlight the relationship between diet, animal performance and mucosal adherent gut microbiota (anterior intestine) in fish fed plant-based diets supplemented with an egg white hydrolysate (EWH) antioxidant anti-obesogenic activity obese rats. The feeding trial juveniles of gilthead sea bream ( Sparus aurata ) lasted 8 weeks. Fish were near visual satiety a meal (FM)/fish oil (FO) based diet (CTRL) or with/without EWH supplementation. Specific growth rate decreased gradually from 2.16% CTRL 1.88% due reduced feed intake, slight impairment conversion ratio. Plant-based triggered hyperplasic inflammation anterior intestine regardless However, ameliorated goblet cell depletion, hepatic intestinal lipid accumulation induced by FM/FO replacement. Illumina sequencing yielded mean 136,252 reads per sample assigned 2,117 OTUs at 97% identity threshold. bacterial diversity was similar all groups, but significantly lower richness found fish. At phylum level, Proteobacteria reached highest proportion fish, whereas Firmicutes Actinobacteria increased restored dietary supplementation, which also amount Bacteroidetes Spirochaetes. closer look, widespread presence Lactobacillales among groups found. Otherwise, polysaccharide hydrolases secretors represented Corynebacterium Nocardioides replacement, mucin-degrading Streptococcus only raised without EWH. In addition, higher abundance Propionibacterium related concentration propionate. antagonism health-promoting propionate cholesterol could explain inferred underrepresentation primary bile acid biosynthesis steroid degradation pathways microbiota. Altogether, these results reinforce central role regulation host metabolism particular, suggesting bioactive peptides as anti-obesity and/or factor