Effects on Digestive, Metabolic and Oxidative Stress Enzymes following Papaya Leaf Meal addition in the Diet of Labeo rohita (Ham.) Fingerlings

A 60-day feeding trial was conducted to evaluate the effect of papaya (Carica papaya) leaf meal on the physio-metabolic enzyme response of Labeo rohita fingerlings. Fingerlings were distributed in five different experimental groups with replicates. Each replicate contains 15 fishes with a mean average initial weight of 11.34 ? 0.20 g?11.61 ? 0.04 g and is fed daily twice for 60 days. Five practical iso-nitrogenous fish diets (~30% protein) were prepared with different levels of papaya leaf meal (PLM) with partial replacement of rice bran, that is T1 (0% PLM), T2 (10% PLM), T3 (15% PLM), T4 (20% PLM) and T5 (25% PLM). The digestive enzymes, such as amylase and protease varied significantly. Amylase activity was significantly higher in the T3 group, while protease activity was highest in the T4 group. The activities of metabolic enzymes, such as alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and malate dehydrogenases were lowest in the T4 and T5 groups. The oxidative stress enzymes were also recorded for their minimum values in the T5 group. The overall results indicate that the fish fed with 20% PLM (T4 group) showed the best performance in terms of growth and physio-metabolic enzyme parameters, although some of the parameters indicated a better value at 25% inclusion. Hence, it can be concluded that PLM can be included up to 20% in the diet of L. rohita (Rohu) fingerlings for optimum production without any deleterious effect on enzyme activity, which is mostly required for fish growth and production. .