Effect of using yeast ( Saccharomyces cerevisiae ) as probiotic on growth parameters, survival and carcass quality in rainbow trout Oncorhynchus mykiss fry

Abstract

The effect of Saccharomyces cerevisia var. elipsoidous as probiotic in the diet of rainbow trout Oncorhynchus mykiss fry was studied during 25 days after the first feed ing in ratios of 1%, 5% and 10%. After 25 days ther e was no significant difference in the fry growth performanc e ( P > 0.05). There was also no significant difference (P > 0.05) in the effect of the dietary yeast on mortality, condi tion factor (CF) and food conversion ratio (FCR). Also an experiment with only fish oil (without yeast) was done and all results were compared with the control group. The specific growth ratio (SGR), body weight increase (%BWG) and protein efficiency ratio (PER) were significantly higher in the 5% yeast diet compared to the control diet ( P < 0.05). A significant increase in the lipid conte nt of the carcass was observed with a probiotic in the diet. With increas e of the yeast in the diet, the ash content of the carcass increased and the protein content decreased. The results of these experiments showed that the use of yeast as additi ve in the diet during the early life stage of the rainbow trout fr y is suitable and it is probable that a 5% concentr ation of yeast in the diet will have the best results on the growth perfo rmance and the feed efficiency ratio.