Effect of different levels of Lactobacillus casei as probiotic on some digestive enzymes of rainbow trout (Oncorhynchus mykiss) fingerlings

Probiotics are generally defined as live microbial food supplement which improves the balance of the host animal’s intestinal flora and the absorption of nutrients from the intestine. The aim of this study was to evaluate the effect of different levels of Lactobacillus casei (PTCC1608) on some digestive enzymes of rainbow trout (Oncorhynchus mykiss)fingerlings. Four thousand eight hundred fingerlings (average weight 32.6±5.5g) were randomly divided into 4 groups with three replicates (each with 400 fish). The control group fed with basal diet and the other groups were fed with 5×106 (A), 5×107 (B) and 5×108(C) CFU/mL L. casei for 60 days. Activities of digestive enzymes were examined at 0 and 60 days of study. Results showed significantly increased intestine enzymes (α-amylase, trypsin, chemotrypsin) of rainbow trout (P0.05). Alkaline phosphatase, lipase and protease activity at 5×106 and5×107CFU/mL concentration on day 60 showed significantly difference compared to the control group (P