Effect of Enterococcus faecalis probiotic on growth, blood parameters and digestive enzymes activity in rainbow trout (Oncorhynchus mykiss)

The present study was conducted to evaluate the effect of supplementation of Enterococcus foecalis ldquo;subspecies NBRC 100480 on the growth performance, blood parameters and digestive enzymes activity of rainbow trout (Oncorhynchus mykiss) for 8 weeks. The experiment was conducted in a completely randomized design with 240 of rainbow trout with average weight of 12 ±1.20 g in 4 treatments and 3 replicates (n=20 in each replicate) and included: control group without using of supplementation of probiotic and another groups the amounts of this probiotic supplement were 3 ×108, 5 ×108, 8 ×108 CFU/g feed. The results showed that the highest final weight and the lowest FCR were observed in treatments containing 5 ×10 8 CFU/g feed and showed significant difference with control and another treatment (p<0.05). The highest protease enzyme activity, RBC, Hb and Htc were observed in treatments containing 5 ×108 and 8 ×108 CFU/g feed (p<0.05). Overall we concluded that the using of 5 ×108 CFU /g feed of E. foecalis in the diet could improve growth, blood parameters and protease enzyme activity of rainbow trout.