本研究旨在研究饮食标准化回肠可消化赖氨酸与净能量(SIDLys:NE)比率对饲喂高小麦饮食的猪脂质代谢的影响。将36只杂交生长的手推车(65.20±0.38kg)封入两个处理组,饲喂高SIDLys:NE比(HR)或低SIDLys:NE比(LR)的高小麦日粮。每个治疗组由三个重复组成,每个复制中每个围栏有六只猪。日粮SIDLys:NE比的降低对car体性状没有不利影响(p>0.05),但增加了背最长肌的大理石花纹得分(p<0.05)。同时,LR饮食倾向于增加血清甘油三酯浓度(p<0.1)。LR饮食上调脂肪酸转运蛋白4和乙酰辅酶A羧化酶α的表达水平,下调脂肪甘油三酯脂肪酶的表达水平(p<0.05)。LR饮食通过降低AMP激活的蛋白激酶(AMPK)α1,沉默蛋白1(SIRT1)的表达水平来改善能量代谢,和过氧化物酶体增殖物激活受体-γ共激活因子-1α(PGC-1α)(p<0.05)。此外,LR饮食通过上调细胞色素P450家族7亚家族A成员1和细胞色素P450家族27亚家族A成员1的表达水平,并下调法尼醇X受体(FXR)和小异二聚体伴侣(SHP)的表达水平来刺激肝胆汁酸合成(p<0.05)。降低的SIDLys:NE比率影响结肠微生物组成,以YRC22、副杆菌属的相对丰度增加为特征,Sphaerochaeta,和拟杆菌,随着罗斯布里亚比例的下降,f_落叶松科_g_梭状芽孢杆菌,肠球菌,Shuttleworthia,Exiguobacterium,棒状杆菌,下颗粒,硫螺旋藻,和马氏杆菌属(p<0.05)。微生物组成的改变伴随着结肠丁酸酯浓度的降低(p<0.1)。代谢组学分析显示LR饮食影响初级胆汁酸合成和AMPK信号通路(p<0.05)。壁炉架分析表明副杆菌属,Sphaerochaeta,f_落叶松科_g_梭状芽孢杆菌,Shuttleworthia,和马氏杆菌属导致了身体代谢的改变。降低饮食SIDLys:NE比率可改善能量代谢,刺激脂肪生成,并通过调节AMPKα/SIRT1/PGC-1α途径和FXR/SHP途径抑制肥育猪的脂解作用。副杆菌属和Sphaerochaeta有利于胆汁酸的合成,而f_Lachnospispiraceae_g_梭菌,Shuttleworthia,马氏杆菌属可能有助于激活AMPK信号通路。总的来说,身体代谢和结肠微生物群共同控制肥育猪的脂质代谢。
The present study aimed to investigate the impacts of dietary standardized ileal digestible lysine to net energy (SID Lys:NE) ratio on lipid metabolism in pigs fed high-wheat diets. Thirty-six crossbred growing barrows (65.20 ± 0.38 kg) were blocked into two treatment groups, fed high-wheat diets with either a high SID Lys:NE ratio (HR) or a low SID Lys:NE ratio (LR). Each treatment group consisted of three replicates, with six pigs per pen in each replicate. The diminishing dietary SID Lys:NE ratio exhibited no adverse impacts on the carcass trait (p > 0.05) but increased the marbling score of the longissimus dorsi muscle (p < 0.05). Meanwhile, LR diets tended to increase the serum triglyceride concentration (p < 0.1). LR diets upregulated fatty acid transport protein 4 and acetyl-coA carboxylase α expression levels and downregulated the expression level of adipose triglyceride lipase (p < 0.05). LR diets improved energy metabolism via decreasing the expression levels of AMP-activated protein kinase (AMPK) α1, sirtuin 1 (SIRT1), and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) (p < 0.05). Additionally, LR diets stimulated hepatic bile acid synthesis via upregulating the expression levels of cytochrome P450 family 7 subfamily A member 1 and cytochrome P450 family 27 subfamily A member 1, and downregulating farnesol X receptor (FXR) and small heterodimer partner (SHP) expression levels (p < 0.05). A lowered SID Lys:NE ratio affected the colonic microbial composition, characterized by increased relative abundances of YRC22, Parabacteroides, Sphaerochaeta, and Bacteroides, alongside a decreased in the proportion of Roseburia, f_Lachnospiraceae_g_Clostridium, Enterococcus, Shuttleworthia, Exiguobacterium, Corynebacterium, Subdoligranulum, Sulfurospirillum, and Marinobacter (p < 0.05). The alterations in microbial composition were accompanied by a decrease in colonic butyrate concentration (p < 0.1). The
metabolomic analysis revealed that LR diets affected primary bile acid synthesis and AMPK signaling pathway (p < 0.05). And the mantel analysis indicated that Parabacteroides, Sphaerochaeta, f_Lachnospiraceae_g_Clostridium, Shuttleworthia, and Marinobacter contributed to the alterations in body metabolism. A reduced dietary SID Lys:NE ratio improves energy metabolism, stimulates lipogenesis, and inhibits lipolysis in finishing pigs by regulating the AMPKα/SIRT1/PGC-1α pathway and the FXR/SHP pathway. Parabacteroides and Sphaerochaeta benefited bile acids synthesis, whereas f_Lachnospiraceae_g_Clostridium, Shuttleworthia, and Marinobacter may contribute to the activation of the AMPK signaling pathway. Overall, body metabolism and colonic microbiota collectively controlled the lipid metabolism in finishing pigs.