Comparison Of Glucose And Lipid Metablism And SREBP-1c Transcriptional Regulation On Glucokinase In Liver And Psoas Muscle Of Weaned Piglets

Erhualian is a local pig breed around China’s Taihu Lake Basin, which is well-known for its docile temperament, high litter volume, high fat accumulation and high level tolerance to tough environment. While Large White is a pig breed imported from foreign country, it has high lean-meat percent and grows fast, but it’s impatient, irritable and its tolerance to hard environment is much lower compared to Erhualian. Glucokinase is a key enzyme in glucose metabolism. Liver and muslce are two critical tissues for glucose homeostasis, so it’s important to explore GCK transcription regulation in liver and psoas muscle of weaned Erhualian and Large White, this may reveal breed effects on glucose metabolism in swine. In this study, for Erhualian and Large White, body weights at the weaning time were recorded, while their serum hormones concentrations and energy metabolic parameters were analyzed. In addition, gene expresions of GCK in liver and psoas muscle were compared between the two breeds as well as its enzyme activity. Furthermore, mRNA levels of SREBP-lc gene were compared in liver and psoas muscle of the two breeds, and the enrichment levels of SREBP-lc binding to the GCK promoter were also measured.1Metabolic profiles in serum, liver and psoas muscle of Erhualian and Large WhiteAfter weaning, two male piglets sharing the same weight with average litter weight were selected randomly, three litters were picked each species, and each species had six piglets in total. Weighted them before slaughter, and then collected blood, liver, and psoas muscle samples. Cholesterol and triglyceride and other indicators in serum liver and psoas muscle were detected. The results showed that: Body length (P<0.01), body weight (P<0.01), hippocampus weight (P<0.01), longissimus muscle weight (P<0.01), psoas muscle weight (P<0.01), liver weight (P<0.01) and longissimus muscle weight/body weight (P<0.01) of Erhualian are significantly lower than Large White, hippocampus weight/body weight (P<0.01) of Erhualian is significantly higher than Large White; Erhualian serum leptin (P<0.05), and triglycerides (P<0.05) are significantly higher than Large White, cortisol (P<0.01), lactate (P<0.01), cholesterol (P<0.01), high density lipoprotein (P<0.01), low-density lipoprotein (P<0.01) and testosterone (P<0.01) levels are significantly higher than Large White. Other indicators have not significant differences. The results indicate that energy metabolism in liver and psoas muscle of Erhualian and Large White behaves differently.2SREBP-lc transcription regulation to GCK in Erhualian and Large Whites’1liver and psoas muscleWe measured liver and psoas muscle together with GCK activity and mRNA levels of related genes. Finally, we used ChIP to detect whether SREBP-lc can regulate GCK transcription in liver and psoas muscle. Results showed that:Erhualian glycogen content (P<0.05) are significantly higher than Large White, AMP levels(P <0.05) are significantly lower than Large White, cytochrome C oxidase subunit III (P <0.05) mRNA levels were significantly lower than Large White; liver SREBP-1(P<0.05) and GCK (P<0.05) mRNA levels are significantly higher compared to Large White, low-density lipoprotein receptor (P<0.01) mRNA levels are significantly higher than Large White. No significant differences are detected in other indicators. ChIP result shows that GCK binded by SREBP-lc in liver and psoas muscle of Erhualian and Large White has no significant differences. These results above suggest that, GCK gene may lead Erhualian and Large White liver and psoas muscle energy metabolism difference, meanwhile, the transcription factor SREBP-lc may not be involved in transcriptional regulation for GCK.