Yi Xin, Yi Simeng, Wang Jinze, Ye Boping, Zhu Xiaowen, Meng Qingxiang, Wu Hao, Zhou Zhenming
State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Anim Nutr. 2025 Jul 12;22:214-229. doi: 10.1016/j.aninu.2025.03.019. eCollection 2025 Sep.
This study investigated lipid metabolism differences between low and high residual feed intake (LRFI and HRFI) bulls. Fifty-five Simmental bulls (449.84 ± 8.49 kg) were fed the same diet for 161 d to determine RFI values. At the end of experiment, back fat thickness (BFT) and rib eye area (REA) were measured via ultrasound, and serum samples were collected for lipid metabolism indicators. Post-slaughter, subcutaneous adipose tissue was analyzed for lipid metabolism indicators, histology, transcriptomics, and lipid metabolomics. Results 1) Ultrasound showed LRFI bulls had lower BFT ( = 0.031) but higher REA ( = 0.021). 2) Serum total cholesterol ( = 0.028) and low-density lipoprotein cholesterol ( = 0.015) were lower in LRFI bulls. Leptin levels were lower in both serum ( = 0.007) and adipose tissue ( = 0.001) in LRFI bulls, as were acetyl-CoA carboxylase levels in serum ( = 0.032) and adipose tissue ( = 0.043). Conversely, adipose triglyceride lipase levels were higher in both serum ( = 0.045) and adipose tissue ( = 0.043), while adipose tissue fatty acid synthase levels were lower ( = 0.035) in LRFI bulls. 3) Transcriptomics identified two pathways, adenosine monophosphate-activated protein kinase (AMPK) and cyclic adenosine monophosphate (cAMP), involving five lipid metabolism-related genes. Among these, adenylate cyclase activating polypeptide 1 receptor type 1 (), adenylate cyclase 10 (), and adenylate cyclase activating polypeptide 1 () were significantly upregulated ( < 0.05), while leptin receptor () was downregulated ( = 0.047) in LRFI bulls. Additionally, leptin () showed a downward trend ( = 0.098) in LRFI bulls. 4) Lipid metabolomics revealed that the LRFI group had significantly higher levels of wax ester (WE) ( = 0.040) and significantly lower levels of monogalactosyldiacylglycerol (MGDG) ( = 0.040) compared to the HRFI group. Additionally, sphingomyelin (SPH) showed a trend towards lower abundance ( = 0.054), and C12:0 levels tended to be higher ( = 0.089) in the LRFI group. In conclusion, differences in the AMPK and cAMP signaling in adipose tissue are associated with reduced lipid synthesis and enhanced lipid degradation in LRFI bulls, which may contribute to reduced lipid deposition.
本研究调查了低剩余采食量（LRFI）和高剩余采食量（HRFI）公牛之间的脂质代谢差异。55头西门塔尔公牛（449.84±8.49千克）被饲喂相同的日粮161天以确定采食量剩余值（RFI）。实验结束时，通过超声测量背膘厚度（BFT）和眼肌面积（REA），并采集血清样本用于脂质代谢指标检测。屠宰后，分析皮下脂肪组织的脂质代谢指标、组织学、转录组学和脂质代谢组学。结果：1）超声显示LRFI公牛的BFT较低（P = 0.031），但REA较高（P = 0.021）。2）LRFI公牛的血清总胆固醇（P = 0.028）和低密度脂蛋白胆固醇（P = 0.015）较低。LRFI公牛血清（P = 0.007）和脂肪组织（P = 0.001）中的瘦素水平较低，血清（P = 0.032）和脂肪组织（P = 0.043）中的乙酰辅酶A羧化酶水平也较低。相反，LRFI公牛血清（P = 0.045）和脂肪组织（P = 0.043）中的脂肪甘油三酯脂肪酶水平较高，而脂肪组织中的脂肪酸合酶水平较低（P = 0.035）。3）转录组学鉴定出两条途径，即腺苷酸活化蛋白激酶（AMPK）和环磷酸腺苷（cAMP），涉及五个与脂质代谢相关的基因。其中，LRFI公牛中1型腺苷酸环化酶激活多肽受体（ADCYAP1R1）、腺苷酸环化酶10（ADCY10）和腺苷酸环化酶激活多肽1（ADCYAP1）显著上调（P < 0.05），而瘦素受体（LEPR）下调（P = 0.047）。此外，LRFI公牛中的瘦素（LEP）呈下降趋势（P = 0.098）。4）脂质代谢组学显示，与HRFI组相比，LRFI组的蜡酯（WE）水平显著较高（P = 0.040），单半乳糖二酰基甘油（MGDG）水平显著较低（P = 0.040）。此外，LRFI组中的鞘磷脂（SPH）丰度呈下降趋势（P = 0.054），C12:0水平趋于较高（P = 0.089）。总之，脂肪组织中AMPK和cAMP信号的差异与LRFI公牛脂质合成减少和脂质降解增强有关，这可能有助于减少脂质沉积。
