Effects of starvation and refeeding on expression of ghrelin and leptin gene with variations in metabolic parameters in Labeo rohita fingerlings

A study was conducted to evaluate the effect of starvation and refeeding on ghrelin and leptin gene expression in Labeo rohita fingerlings. Further, the variations in digestive, metabolic enzymes and metabolites such as glucose, glycogen and lipids were also revealed. An experimental trial of 15 days was carried out, with 7 days of starvation and then refeeding up to 15 days. Sampling was done at different time intervals of 0, 0.5, 1, 2, 3, 5, 7, 10 and 15th day of the experiment. The ghrelin gene expression levels increased significantly (p < 0.05) up to 7th day and decreased after refeeding. Leptin levels showed the opposite trend with decline in expression levels during starvation and declined to the levels of control after refeeding. The activities of digestive enzymes protease, amylase and lipase enzymes were significantly lowest (p < 0.05) on 7th day of starvation and they increased after refeeding the fishes. Hexokinase and G6PDH activities were decreased with days of starvation while LDH and G6Pase significantly increased with starvation. Glycogen showed significant (p < 0.05) reduction during starvation and relapsed to the level of control after refeeding, revealing the role of glycogen stores during starvation. The present study revealed the orexigenic role of ghrelin and anorexigenic role of leptin during starvation and refeeding in L. rohita which aids in maintaining the energy homeostasis through regulating nutrient metabolism. The study also concludes that L. rohita can sustain 7 days of starvation with the aid of metabolic and endocrine regulation of energy homeostasis.