母猪妊娠后期热应激对仔猪肌纤维发育的影响

Effects of heat stress in late gestation of sows on muscle fiber development of piglets

[目的]本文旨在探讨母猪妊娠后期热应激对子代骨骼肌分化、发育、凋亡等的影响。[方法]选取12头预产期相似的(大白×长白)母猪,在妊娠后期(妊娠84 d)随机分为热应激组(HS,28~32℃)和对照组(CON,18~22℃)。母猪分娩后,每窝取一头断奶仔猪采集背最长肌(LD),用Western blot检测样品中相关蛋白的表达情况。[结果]在母猪妊娠后期,热应激显著提高初乳中INF-γ和COR的含量(P<0.05);母猪妊娠后期热应激造成断奶仔猪LD中MyoD蛋白表达水平显著降低(P<0.05),Myogenin蛋白表达水平显著升高(P<0.05),显著提高断奶仔猪LD中肌纤维类型MyHCⅡb的蛋白表达水平(P<0.05),但MyHCⅡx蛋白表达水平没有显著变化(P>0.05)。糖代谢相关蛋白检测结果表明,母猪妊娠后期热应激显著降低断奶仔猪LD中糖代谢相关蛋白PCK1和GLUT4的表达水平(P<0.05);凋亡相关蛋白检测结果表明,母猪妊娠后期热应激造成断奶仔猪LD中凋亡相关蛋白Bax和Bcl-2表达水平显著升高(P<0.05)。[结论]母猪妊娠后期热应激可以显著降低断奶仔猪的体重和LD重,可能与MyoD在断奶仔猪LD中表达水平降低和糖代谢水平降低有关。

[Objectives]The paper aimed to investigate the effects of heat stress in late gestation on differentiation,development and apoptosis of piglet skeletal muscle.[Methods]Twelve sows(Dabai×Changbai)with similar due dates were selected,in the late gestation(84 days of gestation),the sows were randomly divided into heat stress group(HS,28-32℃)and control group(CON,18-22℃).After farrowing,longissimus dorsi(LD)was collected from one weaning piglet per litter.Western blot was used to detect the expression of related proteins in the samples.[Results]Heat stress of sows during late gestation significantly increased the contents of INF-γand COR in colostrum(P<0.05);heat stress in late gestation of sows significantly decreased MyoD protein expression level of LD(P<0.05),and increased Myogenin protein expression level of LD(P<0.05);and heat stress in late pregnancy of sows,the protein expression level of MyHCⅡb in LD of weaning piglets significantly increased(P<0.05),but MyHCⅡx protein expression level had no significant changes(P>0.05);the glucose metabolism-related protein expression showed that heat stress in late gestation of sows significantly reduced PCK1 and GLUT4 expression levels in LD of weaning piglets(P<0.05);the expression levels of apoptosis-related proteins Bax and Bcl-2 in LD of weaning piglets significantly increased by heat stress during late gestation(P<0.05).[Conclusions]Heat stress in sows during late gestation could significantly reduce the body weight and LD weight of weaning piglets,it might be related to the decreased expression level of MyoD and glucose metabolism in LD of weaning piglets.