The impact of hibernation and arousal on energy metabolism and antioxidant defenses in leech (Whitmania pigra)

Whitmania pigra is an important medicinal resource that is widely farmed in aquaculture in Asia, and a decrease in body weight occurring during hibernation and hibernation lasting long time has serious impacts on production efficiency in aquaculture system. We examined energy metabolic and antioxidant enzymes of intestine from a hibernator (W. pigra) over cycles of hibernation‐arousal. Results of the study demonstrated that hibernation in W. pigra was characterized by a profound decrease in energy metabolic during deep hibernation that was interrupted by rewarming arousal. And energy metabolic increased significantly during the rewarming arousal. Regulated suppression of energy metabolism probably contributes to energy savings. Oxidative stress decreased during deep hibernation along with a reduction in oxidative metabolism, but increased during entrance into hibernation and arousal from hibernation. This up‐regulation of antioxidant defense (AD) during arousal was interpreted as protection of the intestine against oxidative damage to come with the enormous increase in metabolic activity during arousal from hibernation, and the up‐regulation of AD during entrance into hibernation was interpreted that leech are exposed to significant stresses (cold acclimation) that must be dealt with appropriately to avoid irreversible tissue damage. It can be concluded that W. pigra has a strong AD system that protects it from the injurious effects of free radicals either during periods of entrance into hibernation and arousal. These results indicate the adaptive mechanism of hibernation that may be applied to increase production efficiency of leech by interrupting or shortening hibernation.