EFFECTS OF HEAT KILLED Lactobacillus plantarum L-137 (HK L-137) SUPPLEMENTAL DIETS ON GROWTH PERFORMANCE AND IMMUNE RESPONSE OF JUVENILE STRIPED CATFISH Pangasianodon hypophthalmus

The present study was conducted to determine the effects of dietary heat killed  Lactobacillus plantarum (HK-L137) on growth, survival, and immune response of juvenile striped catfish (Pangasianodon hypophthalmus). A 60-day feeding trial was carried out and four replicates groups of experimental fish (initial wt. 0.06 g) were fed with respective test diets containing four different concentrations of HK L-137 (0 ppm as control diet , 10 ppm, 20 ppm and 50 ppm ). At the end of the feeding trial, results showed that the dietary supplementation of HK L-137 significantly enhanced the final weight (W_f ), weight gain (WG) and specific growth rate (SGR) of juvenile striped catfish fed the diets containing 20 ppm and 50 ppm HK L-137 (p< 0.05). Simultaneously, the survival rate of experimental fish fed the diet contains 50 ppm HK L-137 was significantly higher than the HK L-137 free group of fish fed with basal diet (p<0.05). In addition , the highest protein efficiency ratios (PER) were also recorded in HK L-137 supplemented groups. Moreover, feed conversion ratio (FCR) of HK L-137 supplemented groups were also significantly lower than the control group. Furthermore, the dietary supplementation of HK L-137 improved and augmented the immune parameters including lysozyme activity, the number of RBC and WBC of juvenile striped catfish. Thereafter, a 14-day bacterial challenge experiment was also carried out and the highest mortality rate (100%) was recorded in the p ositive-control group of fish fed with basal diet. Consequently, post challenge survival rates (PCSR) of HK L-137 supplemented groups were higher than the control group. Present study demonstrated that the dietary supplementation of HK L-137 has the tremendous positive-effects on SR, FCR, WG, SGR, FI, PER, immune response and disease resistanc e of juvenile striped catfish.