Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China.
Eur J Nutr. 2018 Apr;57(3):991-1001. doi: 10.1007/s00394-017-1383-5. Epub 2017 Feb 23.
The study aimed to determine the effects of maternal low-protein (LP) diet on subcutaneous fat deposition of weaning piglets and the potential mechanism.
Sows were fed either a standard protein (SP, 15 and 18% crude protein) or a LP diet (50% protein levels of SP) throughout pregnancy and lactation. Subcutaneous fat and blood were sampled from male piglets at 28 days of age. Serum biochemical metabolites and hormone concentrations were detected with the enzymatic colorimetric methods. Serum-free amino acid (FAA) levels were measured by amino acid auto-analyzer. The mRNA and protein were measured by qRT-PCR and Western blot.
Body weight, back fat thickness, triglycerides concentrations in subcutaneous fat tissue, and serum, as well as FFA concentrations were significantly reduced in LP piglets when compared with SP piglets. Further studies showed that mRNA and protein expression of acetyl-CoA carboxylase and fatty acid synthetase, two key enzymes of de novo lipogenesis, were significantly reduced in LP piglets, while mRNA expression and the lipolytic enzymes activities of lipolysis genes, adipose triglyceride lipase and hormone-sensitive lipase, were significantly increased. Furthermore, expression of autophagy-related gene 7 and autophagy maker gene microtubule-associated protein 1A/1B-light chain 3 (LC 3) as well as the conversion of LC3I to LC3II were significantly elevated, along with the expression of activating transcription factor-4 and eukaryotic translation initiation factor-2a.
These results indicate that amino acid starvation-induced autophagy is involved in reduced subcutaneous fat deposition in maternal LP weaning piglets, demonstrating links between maternal protein restriction and offspring fat deposition.
本研究旨在确定母体低蛋白（LP）饮食对断奶仔猪皮下脂肪沉积的影响及其潜在机制。
母猪在整个妊娠期和哺乳期分别喂食标准蛋白（SP，粗蛋白 15%和 18%）或 LP 饮食（SP 蛋白水平的 50%）。在 28 日龄时，从雄性仔猪中采集皮下脂肪和血液。采用酶比色法检测血清生化代谢物和激素浓度。采用氨基酸自动分析仪测定血清游离氨基酸（FAA）水平。通过 qRT-PCR 和 Western blot 测定 mRNA 和蛋白质。
与 SP 仔猪相比，LP 仔猪的体重、背脂厚度、皮下脂肪组织和血清中的甘油三酯浓度以及 FFA 浓度均显著降低。进一步研究表明，LP 仔猪中从头合成脂肪的两个关键酶乙酰辅酶 A 羧化酶和脂肪酸合成酶的 mRNA 和蛋白表达显著降低，而脂肪分解基因脂肪甘油三酯脂肪酶和激素敏感脂肪酶的 mRNA 表达和脂肪酶活性显著增加。此外，自噬相关基因 7 和微管相关蛋白 1A/1B-轻链 3（LC3）的自噬标记基因的表达以及 LC3I 向 LC3II 的转化显著升高，同时激活转录因子 4 和真核翻译起始因子 2a 的表达也升高。
这些结果表明，氨基酸饥饿诱导的自噬参与了母体 LP 断奶仔猪皮下脂肪沉积的减少，表明母体蛋白质限制与后代脂肪沉积之间存在联系。
