The study of modulation of gut microbiota of Caspian white fish (Rutilus frisii kutum) through administration of yeast based prebiotic

The intestinal microbiota of fish belongs to different species compare to terrestrial animals, mainly Gram-negative bacteria are predominant. Despite importance as probiotic, gram-positive bacteria like Lactobacillus Sp. are minor constitutes of gut microbiota. The aim of this study was to investigate the possibility of modulation of Kutum intestinal microbiota and elevation of lactic acid bacteria (LAB) levels through administration of yeast based prebiotic. The study was performed as randomized design with 5 treatments and 3 replications in which kutum were fed different levels, 0, 0.5, 1, 1.5 and 2 % of yeast based prebiotic for 60 days. At the end of the trial, culture based analysis of intestinal microbiota include lactic acid bacteria levels, total bacteria and obligatory anaerobic bacteria were performed by using MRS, TSA, SPS media. Also, the isolated lactic acid bacteria species were determined by biochemical test. The highest and lowest lactic acid bacteria levels observed in 0.5 % treatment and control treatment, respectively (P value > 0.05). Also, administration of 0.5 % yeast based prebiotic significantly increased total viable bacteria (P value > 0.05). The highest and lowest obligatory anaerobic bacteria were recorded in control and 0.5 and 1 % treatment (P value> 0.05). The biochemical test revealed isolation of three species Lactobacillus plantarum, L. caseie, L. acidophilous in the intestinal microbiota after administration of yeast based prebiotic. Discussion and The results of this study determined that administration of 0.5 % yeast based prebiotic significantly modulates the intestinal microbiota of kutum fry toward potentially beneficial communities (i.e LAB).