Supplementation of exogenous enzymes in Catla catla diets: effects on the physiology and antioxidant enzyme activity.

This study examined the impacts of adding exogenous enzymes on the growth, nutrient digestibility, carcass composition and antioxidant enzyme activities of Catla catla fingerlings fed test diets based on cottonseed meal. Six experimental diets were created, each containing 200 mgkg^-1 of enzyme supplements. The diets consisted of a control diet (CON) without enzyme supplements and five treatment diets: four single-enzyme supplements, namely phytase (PHY), xylanase (XYL), protease (PRO), and cellulase (CEL), and a fifth treatment diet containing a mixture (MIX) of all four enzyme supplements. Fingerlings (7.74 ± 0.30 g each) were introduced into V-shaped water tanks that were intended to hold waste. For seventy days, fish in three replicate tanks received feed at a rate of five percent of their live body weight. The results indicated that the MIX yielded the most favorable outcomes, followed by PHY, XYL, and CEL, while PRO and CON group showed negligible differences. Notably, the MIX supplementation resulted in maximum specific growth rate, weight gain percentage, and minimum feed conversion ratio, surpassing the CON group. Furthermore, the MIX at 200 mgkg^-1 demonstrated optimal digestibility and carcass composition in C. catla. Additionally, the activity of antioxidant enzymes, including superoxide dismutase, peroxidase, and catalase, exhibited enhanced performance in response to exogenous MIX enzyme supplementation. Therefore, these findings suggest that an enzyme MIX group supplemented at 200 mgkg^-1, is optimal for promoting growth, nutrient digestibility, carcass composition, and antioxidant enzyme activity in C. catla.