α-酮戊二酸对脂多糖应激仔猪血浆胰岛素、氨基酸含量及腓肠肌mTOR信号传导途径的影响

Effects of α-ketoglutarate on Plasma Concentrations of Insulin and Amino Acids and mTOR Signal Transduction in Gastrocnemius of Piglets Challenged by Lipopolysaccharide

本试验研究了α-酮戊二酸(α-ketoglutarate,AKG)对脂多糖(lipopolysaccharide,LPS)应激仔猪血浆胰岛素、氨基酸浓度及腓肠肌mTOR、p70S6K表达及磷酸化水平的影响。选用18头健康的(24±1)日龄断奶仔猪,随机分成3个处理(对照组、LPS组、AKG-LPS组),每个处理6个重复。各组基础饲粮一致,对照组和LPS组饲喂基础饲粮,AKG-LPS组饲喂基础饲粮+1%AKG。试验期为16 d,于第10、12、14和16天清晨,LPS组和AKG-LPS组仔猪分别腹膜注射80μg/kg的LPS。第16天注射LPS 3 h后,前腔静脉采血。第17天屠宰取腓肠肌待测。LPS应激可提高仔猪血浆谷氨酸(glutamic acid,Glu)浓度(P<0.10),降低血浆胰岛素水平及腓肠肌P-mTOR/T-mTOR和P-p70S6K/T-p70S6K的值(P<0.05);饲粮中添加1%AKG可缓解应激仔猪血浆Glu浓度升高(P<0.05)、胰岛素水平(P<0.10)及腓肠肌P-mTOR/T-mTOR和P-p70S6K/T-p70S6K的值降低(P<0.05)。由此可见,1%AKG可缓解LPS应激造成的血浆胰岛素降低和Glu浓度的升高,显著改善LPS应激导致的腓肠肌mTOR和p70S6K磷酸化水平的降低。

The study was conducted to investigate the effects of α-ketoglutarate（AKG） on concentrations of insulin and amino acids in plasma,expression and phosphorylation levels of mTOR and p70S6K in gastrocnemius of piglets challenged by lipopolysaccharide（LPS）.Eighteen healthy weanling piglets aged（24±1） days were randomly assigned into 3 treatments（6 replicates per group）： control group,LPS group and AKG-LPS group.Piglets in the control and LPS group were fed basal diet,and those in the AKG-LPS group were fed basal diet＋1% AKG.The experiment lasted for 16 days.On d 10,12,14 and 16,piglets in the LPS and AKG-LPS group were injected intraperitoneally with LPS at 80 μg/kg,and those in the control group were injected with the same dose of normal saline.On d 16,blood samples were collected after 3 h of LPS injection.On d 17,gastrocnemius samples of all piglets were collected for analysis after being butchered.LPS challenge increased glutamine concentration（P0.10） and reduced insulin concentration（P0.05） in plasma,while reduced P-mTOR/T-mTOR and P-p70S6K/T-p70S6K in gastrocnemius（P0.05）.Dietary supplementation of 1% AKG alleviated the increase of glutamine concentration（P0.05）,the decrease of plasma insulin concentration（P0.10）,and the decrease of P-mTOR/T-mTOR,and P-p70S6K/T-p70S6K in gastrocnemius（P0.05）.In conclusion,dietary supplementation of 1% AKG can alleviate the decrease of insulin concentration and increase of glutamine concentration in plasma,and significantly alleviate the decrease of phosphorylation of mTOR and p70S6K induced by LPS challenge.