Short-term periodic feed deprivation in Labeo rohita fingerlings: Effect on the activities of digestive, metabolic and anti-oxidative enzymes

This study aimed to determine the effect of periodic feed deprivation on the activities of digestive, metabolic and anti-oxidative enzymes of Labeo rohita (commonly known as rohu) fingerlings. Fish (average weight, 3.73 ± 0.06 g) were periodically starved for 0 (0 day-per-week, dpw), 1 (1 dpw), 2 (2 dpw) or 3 (3 dpw) consecutive day (s) per week for a total duration of 10 weeks. On the day of feeding, fish were fed to satiation twice daily with a diet containing 30% crude protein and 6% lipid. Results showed increased protease and amylase activities in the 1 dpw and 2 dpw groups, suggesting that feeding fish for 6 or 5 days a week markedly improved the digestive capacity of fish when compared to daily feeding (0 dpw). However, the activities of lipase and alkaline phosphatase did not respond significantly (P > 0.05) due to periodic feed deprivation. Periodic feed deprivation of 1 dpw did not lead to any changes in the metabolic and anti-oxidative enzyme activities of the fish. In fingerlings deprived of feed for 2 dpw, higher hepatic glycolytic enzyme activities, hexokinase and pyruvate kinase, were observed but with no change in the activities of gluconeogenic (glucose-6-phosphatase, aspartate amino-transferase and alanine amino-transferase) and Kreb's cycle (malate dehydrogenase) enzymes. The group deprived of feed for 3 dpw exhibited lower activities of malate dehydrogenase, glucose-6-phosphatase and glucose-6-phosphate dehydrogenase. Increased activities of anti-oxidative enzymes, superoxide dismutase and catalase, in the 2 and 3 dpw groups in this study implied an adaptive response of L. rohita fingerlings to cope with the oxidative stress caused due to feed deprivation. Higher activities of protease and amylase in the 1 and 2 dpw groups, and higher key glycolytic enzyme activities in the 2 dpw group would suggest improved digestive and metabolic functions, however, feed deprivation beyond 2 dpw seemed to have adverse effect on L. rohita fingerlings.