In the aquaculture industry, probiotics serve as biofriendly agents that contribute to better growth and health of fish. This study was designed to evaluate the effects of multistrain probiotics (MSP) on growth, whole-body composition, digestive and antioxidant enzymes, hematology, blood biochemistry, and physiological stress parameters in Clarias batrachus fingerlings. Five experimental diets were prepared with supplementation of MSP (Bacillus subtilis, Bacillus licheniformis, and Enterococcus faecalis) powder at 0.5, 1.0, 1.5, and 2.0 g/kg, labeled T0, T1, T2, T3, and T4 diets, respectively. Healthy fish were acclimatized and distributed in 15 aquaria (89 × 58 × 61 cm) in triplicate with an initial weight of 10.13±0.01g. Fish were provided with experimental diets for 90 days @ 5% body weight. After completing the feeding trial, fish were dissected to collect liver (antioxidant enzymes), intestine (digestive enzymes), whole body fish (proximate analysis), and blood (hematology, blood biochemistry, and physiological stress parameters) for analysis. The findings of the current study showed improvements (P<0.05) in the growth performance observed in MSP-enriched groups in comparison to the control. Whole body composition and stress parameters (glucose and cortisol) were not affected by MSP supplementation in diets. Digestive enzyme (amylase, protease, and lipase) and antioxidant enzyme (glutathione peroxidase, superoxide dismutase, catalase, and malondialdehyde) activities in the MSP-supplemented groups were enhanced significantly (P<0.05). Hematological parameters such as white blood cells, red blood cells, hemoglobin, and hematocrit were also significantly increased in response to MSP supplementation in diets. Moreover, an increasing trend in blood biochemistry was observed in the activities of alanine phosphatase, while a decrease in alanine aminotransferase and aspartate aminotransferase was observed. In conclusion, MSP supplementation up to 2.0 g/kg significantly enhanced growth performance, hematology, serum biochemistry, and digestive and antioxidant enzyme activities in C. batrachus.
Keywords: Multistrain probiotics, growth, Clarias batrachus, digestive enzymes, antioxidant status, blood biochemistry