Effect of Lactobacillus plantarum and Lactobacillus delbrueckii subsp. bulgaricus on growth performance, gut microbial flora and digestive enzymes activities in Tor grypus (Karaman, 1971)

In this study, two main probiotics (Lactobacillus plantarum and Lactobacillus delbrueckii subsp. bulgaricus) were isolated from the intestine of Tor grypus and their effects on growth performance, gut microbial flora and digestive enzymes activities (i.e., α-amylase, lipase, trypsin, chymotrypsin, and alkaline phosphatase) of Tor grypus (Karaman, 1971) were determined. Juveniles of T. grypus (n=480, weighing 45±10 g) were randomly divided into 4 equal  groups (with 3 replications) and fed on diets containing 5×107 cfu g-1 of L. plantarum (G1), L. bulgaricus (G2), L. casei (G3) and a control diet (without probiotic) for 60 continuous days. Results showed that probiotic supplementations had generally significant effects on growth performance (p<0.05). The G2 group had the best effect on specific growth rate (SGR) and feed utilization efficiency in T. grypus. The digestive enzyme activities, on day 30 after feeding, significantly increased in G1 when compared with those in the control group (p<0.05). Significant changes in bacterial intestinal flora were observed in all probiotic groups compared with the control (p<0.05). Our results indicated that supplementation of isolated bacteria from the intestine of T. grypus (i.e., G2) can efficiently improve growth performance, intestinal microbiota and some digestive enzyme activities in juvenile T. grypus. Therefore, it can be isolated and used as a growth enhancer just like the commercial probiotics.