Mitochondrial DNA introgression has been suggested to be responsible for the maternal consistent implications. Study on mt-DNA （mitochondrial DNA） variation in the yellowfin tuna （Thunnus albacares） using RFLP （r...Mitochondrial DNA introgression has been suggested to be responsible for the maternal consistent implications. Study on mt-DNA （mitochondrial DNA） variation in the yellowfin tuna （Thunnus albacares） using RFLP （restriction fragment length polymorphisms） has provided the evidence of maternal inheritance of yellowfin tuna in captivity. Eggs were collected in every spawning in 2004-2006 season. The mt-DNA genotypes of broodstock were compared with their eggs and the maternal inheritance of these females was determined from genotypes in the eggs. The result showed that six genotypes of female broodstock were observed in eggs and four of them were found to share a single female＇s identity and one type was shared by two females. The same genotype was observed in almost every sampling throughout the year. The female broodstocks spawned almost daily throughout the season.展开更多
Pyruvate dehydrogenase kinases(PDKs)-pyruvate dehydrogenase E1αsubunit(PDHE1α)axis plays an important role in regulating glucose metabolism in mammals.However,the regulatory function of PDKsPDHE1α axis in the gluco...Pyruvate dehydrogenase kinases(PDKs)-pyruvate dehydrogenase E1αsubunit(PDHE1α)axis plays an important role in regulating glucose metabolism in mammals.However,the regulatory function of PDKsPDHE1α axis in the glucose metabolism of fish is not well known.This study determined whether PDKs inhibition could enhance PDHE1αactivity,and improve glucose catabolism in fish.Nile tilapia fingerlings(1.90±0.11 g)were randomly divided into 4 treatments in triplicate(30 fish each)and fed control diet without dichloroacetate(DCA)(38% protein,7% lipid and 45% corn starch)and the control diet supplemented with DCA,which inhibits PDKs through binding the allosteric sites,at 3.75(DCA3.75),7.50(DCA7.50)and 11.25 g/kg(DCA11.25),for 6 wk.The results showed that DCA3.75,DCA7.50 and DCA11.25significantly increased weight gain,carcass ratio and protein efficiency ratio(P<0.05)and reduced feed efficiency(P<0.05)of Nile tilapia.To investigate the effects of DCA on growth performance of Nile tilapia,we selected the lowest dose DCA3.75 for subsequent analysis.Nile tilapia fed on DCA3.75significantly reduced the mesenteric fat index,serum and liver triglyceride concentration and total lipid content in whole fish,and down-regulated the expressions of genes related to lipogenesis(P<0.05)compared to the control.The DCA3.75 treatment significantly improved glucose oxidative catabolism and glycogen synthesis in the liver,but significantly reduced the conversion of glucose to lipid(P<0.05).Furthermore,the DCA3.75 treatment significantly decreased the PDK2/4 gene and protein expressions(P<0.05),accordingly stimulated PDHE1αactivity by decreasing the phosphorylated PDHE1αprotein level.In addition,DCA3.75 treatment significantly increased the phosphorylated levels of key proteins involved in insulin signaling pathway and glycogen synthase kinase 3β(P<0.05).Taken together,the present study demonstrates that PDK2/4 inhibition by using DCA promotes glucose utilization in Nile tilapia by activating PDHE1αand improving insulin sensitivity.Our study helps to understand the regulatory mechanism of glucose metabolism for improving dietary carbohydrate utilization in farmed fish.展开更多
文摘Mitochondrial DNA introgression has been suggested to be responsible for the maternal consistent implications. Study on mt-DNA （mitochondrial DNA） variation in the yellowfin tuna （Thunnus albacares） using RFLP （restriction fragment length polymorphisms） has provided the evidence of maternal inheritance of yellowfin tuna in captivity. Eggs were collected in every spawning in 2004-2006 season. The mt-DNA genotypes of broodstock were compared with their eggs and the maternal inheritance of these females was determined from genotypes in the eggs. The result showed that six genotypes of female broodstock were observed in eggs and four of them were found to share a single female＇s identity and one type was shared by two females. The same genotype was observed in almost every sampling throughout the year. The female broodstocks spawned almost daily throughout the season.
基金the financial support provided by the National Key R&D Program of China(2018YFD0900400)。
文摘Pyruvate dehydrogenase kinases(PDKs)-pyruvate dehydrogenase E1αsubunit(PDHE1α)axis plays an important role in regulating glucose metabolism in mammals.However,the regulatory function of PDKsPDHE1α axis in the glucose metabolism of fish is not well known.This study determined whether PDKs inhibition could enhance PDHE1αactivity,and improve glucose catabolism in fish.Nile tilapia fingerlings(1.90±0.11 g)were randomly divided into 4 treatments in triplicate(30 fish each)and fed control diet without dichloroacetate(DCA)(38% protein,7% lipid and 45% corn starch)and the control diet supplemented with DCA,which inhibits PDKs through binding the allosteric sites,at 3.75(DCA3.75),7.50(DCA7.50)and 11.25 g/kg(DCA11.25),for 6 wk.The results showed that DCA3.75,DCA7.50 and DCA11.25significantly increased weight gain,carcass ratio and protein efficiency ratio(P<0.05)and reduced feed efficiency(P<0.05)of Nile tilapia.To investigate the effects of DCA on growth performance of Nile tilapia,we selected the lowest dose DCA3.75 for subsequent analysis.Nile tilapia fed on DCA3.75significantly reduced the mesenteric fat index,serum and liver triglyceride concentration and total lipid content in whole fish,and down-regulated the expressions of genes related to lipogenesis(P<0.05)compared to the control.The DCA3.75 treatment significantly improved glucose oxidative catabolism and glycogen synthesis in the liver,but significantly reduced the conversion of glucose to lipid(P<0.05).Furthermore,the DCA3.75 treatment significantly decreased the PDK2/4 gene and protein expressions(P<0.05),accordingly stimulated PDHE1αactivity by decreasing the phosphorylated PDHE1αprotein level.In addition,DCA3.75 treatment significantly increased the phosphorylated levels of key proteins involved in insulin signaling pathway and glycogen synthase kinase 3β(P<0.05).Taken together,the present study demonstrates that PDK2/4 inhibition by using DCA promotes glucose utilization in Nile tilapia by activating PDHE1αand improving insulin sensitivity.Our study helps to understand the regulatory mechanism of glucose metabolism for improving dietary carbohydrate utilization in farmed fish.
