Institute of Feed Sciences, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
The Key Laboratory of Molecular Animal Nutrition (Zhejiang University), Ministry of Education, Hangzhou, College of Animal Sciences, Zhejiang 310058, China.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad294.
Conjugated linoleic acids (CLAs) have served as a nutritional strategy to reduce fat deposition in adipose tissues of pigs. However, the effects of CLAs on lipid profiles in serum and how these lipid molecules regulate fat deposition are still unclear. In this study, we explored the effects of CLAs on regulating lipid deposition in adipose tissues in terms of lipid molecules and microbiota based on a Heigai pig model. A total of 56 Heigai finishing pigs (body weight: 85.58 ± 10.39 kg) were randomly divided into two treatments and fed diets containing 1% soyabean oil or 1% CLAs for 40 d. CLAs reduced fat deposition and affected fatty acids composition in adipose tissues of Heigai pigs via upregulating the expression of the lipolytic gene (hormone-sensitive lipase, HSL) in vivo and in vitro. CLAs also altered the biochemical immune indexes including reduced content of total cholesterol (TChol), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C) and changed lipids profiles including decreased sphingolipids especially ceramides (Cers) and sphingomyelins (SMs) in serum of Heigai pigs. Mechanically, CLAs may decrease peroxisome proliferator-activated receptorγ (PPARγ) expression and further inhibit adipogenic differentiation in adipose tissues of pigs by suppressing the function of Cers in serum. Furthermore, Pearson's correlation analysis showed HSL expression was positively related to short-chain fatty acids (SCFAs) in the gut (P ≤ 0.05) but the abundance of Cers was negatively related to the production and functions of SCFAs (P ≤ 0.05). CLAs altered the distribution of the lipid in serum and inhibited adipogenic differentiation by suppressing the function of Cers and further decreasing PPARγ expression in adipose tissues of Heigai pigs. Besides, the HSL expression and the abundance of Cers are associated with the production and functions of SCFAs in the gut.
共轭亚油酸（CLA）已被用作减少猪脂肪组织中脂肪沉积的营养策略。然而，CLA 对血清中脂质谱的影响以及这些脂质分子如何调节脂肪沉积仍不清楚。在这项研究中，我们基于黑盖猪模型，从脂质分子和微生物组的角度探讨了 CLA 调节脂肪组织中脂质沉积的作用。共选择 56 头体重为（85.58±10.39）kg 的黑盖育肥猪，随机分为 2 个处理组，分别饲喂添加 1%大豆油或 1%CLA 的日粮 40d。CLA 降低了脂肪沉积，并通过体内和体外上调脂肪分解基因（激素敏感脂肪酶，HSL）的表达，影响了黑盖猪脂肪组织中脂肪酸的组成。CLA 还改变了生化免疫指标，包括总胆固醇（TChol）、高密度脂蛋白（HDL-C）和低密度脂蛋白（LDL-C）含量降低，以及黑盖猪血清中脂质谱改变，包括鞘脂（Cer）和神经鞘磷脂（SM）特别是 ceramides（Cers）和 sphingomyelins（SMs）减少。在机制上，CLA 可能通过抑制血清中 Cers 的功能，降低过氧化物酶体增殖物激活受体γ（PPARγ）的表达，进一步抑制脂肪组织中猪的脂肪生成分化。此外，皮尔逊相关分析显示，HSL 表达与肠道中的短链脂肪酸（SCFAs）呈正相关（P≤0.05），而 Cers 的丰度与 SCFAs 的产生和功能呈负相关（P≤0.05）。CLA 通过抑制 Cers 的功能，降低脂肪组织中 PPARγ 的表达，改变血清中脂质的分布，抑制脂肪生成分化。此外，HSL 表达和 Cers 的丰度与肠道中 SCFAs 的产生和功能有关。
