Effects of yeast (Saccharomyces cerevisiae) on the intestinal microbiota of GIFT Tilapia (Oreochromis mossambicus)

This study was conducted to assess the impact of yeast (Saccharomyces cerevisiae) as potential probiotic for improving the intestinal microbiota of GIFT Tilapia (Oreochromis mossambicus) as improved intestinal microbiota can enhance the resistance and improve the gut morphology. The study was carried out for 60 days to investigate the influence of different levels (0.15%, 0.30%, 0.45%, 0.60%, 0.75% and 1%) of S.cerevisiae (named as SC1, SC2, SC3, SC4, SC5 and SC6). Isolation and identification of intestinal microbiota was conducted as describe in methods. The results showed significantly better effects on intestinal microbiota (P<0.05) as compared to control. The maximum number of intestinal microbiota was observed in SC4 (5.5×108 CFU/ ml) treatment. In this study, various strains of intestinal bacteria were isolated and identified. A total of 384 bacterial strains were isolated from the fish and classified into six taxonomic groups; Acinetobacter, Bacillus, Enterobacteriaceae, Vibrio, Pseudomonas and Vibrionaceae (Aeromonas). The significant difference was observed in Vibrionaceae (P<0.05), while highly significant (P<0.01) differences were observed in Acinetobacter, Enterobactericeae, Pseudomonas, other gram negative and gram-positive bacteria counts in treatments fed with dietary probiotics as compared to control. It can be concluded that the addition of 0.60% S. cerevisiae in the diet can enhance the intestinal microbiota of GIFT Tilapia.