Gut health improvement as a result of dietary supplementation of VILIGEN™ in juvenile Nile tilapia.

This study aimed to evaluate the inclusion of VILIGEN™, a blend containing sodium butyrate, dehydrated hydrolyzed yeast, and zinc proteinate, on the profile of the allochthonous intestinal microbial community, the activity of digestive enzymes, and the integrity of the intestinal barrier of juvenile Nile tilapia, <italic>Oreochromis niloticus</italic>. A feeding trial was conducted with five VILIGEN™ doses (0.00, 0.60, 1.20, 2.40, and 4.80 g kg−1). The fish were randomly distributed into four groups per treatment, with 28 fish for experimental unit. Fish were fed to apparent satiety twice daily for 60 days. The gut medial portion was collected for enzyme activity and morphological analyses, while feces samples from the same gut portion were sampled for microbial characterization. Morphological indexes and structure of the intestinal physical barrier were determined by scanning and transmission electron microscopy. The tight junction proteins were quantified by western blot. Fish-fed diets containing VILIGEN™ showed the greatest alpha diversity and abundance of the phyla Actinobacteria and Proteobacteria and the genera <italic>Legionella</italic>, <italic>Aquisphaera</italic>, <italic>Bacillus</italic>, and <italic>Gordonibacter</italic>. Trypsin activity was higher in the gut of fish-fed VILIGEN™ supplemented diets. Regarding the greatest intestinal tissue integrity, fish-fed diets containing 2.40 g kg−1 VILIGEN™ showed the lowest fusion of the gut folds and the highest development and microvilli height. VILIGEN™ showed beneficial effects for Nile tilapia gut health, presented a positive modulatory effect on the morphology and integrity of the intestinal epithelium, increased trypsin activity, and modulated gut microbial community, including high alpha diversity of bacterial species in the gut. [ABSTRACT FROM AUTHOR]