Regulatory metabolism over the hibernation‐activity cycle changes contribute to the adaptive enhancement of leech ( Whitmania pigra )

Abstract

Whitmania pigra is an economically important medicinal and aquaculture species in China, but weight greatly reducing during hibernation seriously affects the production efficiency of aquaculture systems. We studied the levels of metabolites, metabolic enzymes in leech intestine in five hibernation-activity states. 1099 and 1766 metabolites were identified. 232 metabolites were up-regulated, and 123 metabolites were down-regulated during deep hibernation, 43 of them decreased and 30 of them increased in active after hibernation. Comprehensive analysis shows that metabolism was repressed globally in hibernation, including glycolysis, TCA, mitochondrial respiratory, which resulted in ATP synthesis decreased. Meanwhile, decreased glycolysis, increased beta-oxidation showed a shift of fuel use from carbohydrates to lipids. During hibernation, beta-oxidation elevated but MDA level remained stable along with glutathione antioxidant system inclined, other adaptive cytoprotection like PUFA elevated and membrane phospholipids remodelled. During arousal, oxidative stress increased, manifested by an increase in glutathione antioxidant system and MDA, which may be due to excessive production of reactive oxygen that accompany metabolism recovery during arousal. By the metabolism analysis in this study, we come closer to fully uncovering the mechanism of leech hibernation that may be applied to prevent pathological stress responses or metabolic dysregulation when interrupting or shortening leech hibernation.