Hu Liang, Han Fei, Chen Lin, Peng Xie, Chen Daiwen, Wu De, Che Lianqiang, Zhang Keying
Institute of Animal Nutrition, Key Laboratory of Animal Disease-Resistance Nutrition, Sichuan Agricultural University, Ministry of Education, No.211 Huimin Road, Wenjiang District, Chengdu, 611130 Sichuan People's Republic of China.
Genes Nutr. 2018 Jul 27;13:23. doi: 10.1186/s12263-018-0612-8. eCollection 2018.
Intrauterine growth-restricted (IUGR) neonates impair postnatal skeletal muscle growth. The aim of this study was to investigate whether high nutrient intake (HNI) during the suckling period could improve muscle growth and metabolic status of IUGR pigs.
Twelve pairs of IUGR and normal birth weight (NBW) pigs (7 days old) were randomly assigned to adequate nutrient intake and HNI formula milk groups. Psoas major (PM) muscle sample was obtained after 21 days of rearing.
IUGR decreased cross-sectional areas (CSA) and myofiber numbers, activity of lactate dehydrogenase (LDH), and mRNA expression of insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), mammalian target of rapamycin (mTOR), ribosomal protein s6 (RPS6), eukaryotic translation initiation factor 4E (eIF4E), protein expression of phosphorylated mTOR (P-mTOR), and phosphorylated protein kinase B (P-Akt) in the PM muscle of pigs. Irrespective of birth weight, HNI increased muscle weight and CSA, the concentration of RNA, and ratio of RNA to DNA, as well as ratio of LDH to β-hydroxy-acyl-CoA-dehydrogenase in the PM muscle of pigs. Furthermore, HNI increased percentages of MyHC IIb, mRNA expression of IGF-1, IGF-1R, Akt, mTOR, RPS6, and eIF4E, as well as protein expression of P-mTOR, P-Akt, P-RPS6, and P-eIF4E in the PM muscle of pigs.
The present findings suggest that high nutrient intake during the suckling period could improve skeletal muscle growth and maturity, which is associated with increasing the expression of protein deposition-related genes and accelerating the development of glycolytic-type myofiber in pigs.
宫内生长受限（IUGR）新生儿会损害出生后骨骼肌的生长。本研究的目的是调查哺乳期高营养摄入（HNI）是否能改善IUGR仔猪的肌肉生长和代谢状况。
将12对IUGR和正常出生体重（NBW）的仔猪（7日龄）随机分为营养摄入充足组和HNI配方奶组。饲养21天后获取腰大肌（PM）肌肉样本。
IUGR降低了仔猪PM肌肉的横截面积（CSA）、肌纤维数量、乳酸脱氢酶（LDH）活性、胰岛素样生长因子1（IGF-1）、IGF-1受体（IGF-1R）、雷帕霉素靶蛋白（mTOR）、核糖体蛋白s6（RPS6）、真核翻译起始因子4E（eIF4E）的mRNA表达、磷酸化mTOR（P-mTOR）和磷酸化蛋白激酶B（P-Akt）的蛋白表达。无论出生体重如何，HNI均可增加仔猪PM肌肉的重量和CSA、RNA浓度、RNA与DNA的比率以及LDH与β-羟酰基辅酶A脱氢酶的比率。此外，HNI还增加了仔猪PM肌肉中肌球蛋白重链IIb（MyHC IIb）的百分比、IGF-1、IGF-1R、Akt、mTOR、RPS6和eIF4E的mRNA表达，以及P-mTOR、P-Akt、P-RPS6和P-eIF4E的蛋白表达。
目前的研究结果表明，哺乳期高营养摄入可改善骨骼肌的生长和成熟，这与增加蛋白质沉积相关基因的表达以及加速仔猪糖酵解型肌纤维的发育有关。
