Data_Sheet_1_Lactobacillus delbrueckii might lower serum triglyceride levels via colonic microbiota modulation and SCFA-mediated fat metabolism in parenteral tissues of growing-finishing pigs.docx

Gut microbiota and its metabolites play a key role in host metabolism. Our previous study found supplemental Lactobacillus delbrueckii affected lipid metabolism of pigs, however, the underlying mechanism is unclear. In this study, we investigated the effects of L. delbrueckii on colonic bacteria composition and its metabolites, serum lipids and hormone levels, fat metabolism related enzyme activity and gene expression in various tissues of growing-finishing pigs. Twelve pigs were randomly distributed into two groups (n = 6), and pigs in each group were fed diets with (Con + LD) or without (Con) 0.1 % L. delbrueckii for 28 days. Results exhibited the deceased triglyceride (TG) levels and elevated free fatty acid (FFA) contents in serum and increased concentrations of butyric acid in colonic digesta after L. delbrueckii supplementation. Dietary L. delbrueckii increased abundance of Lactobacillus and Butyrivibri and tended to increase abundance of Akkermansia and Megasphaera in colonic digesta. L. delbrueckii consumption up-regulated glucagon-like peptide1 (GLP-1), monocarboxylate transporter1 (MTC1) and sodium-dependent monocarboxylate transporter1 (SMCT1) expression in colonic tissue. Administration of L. delbrueckii tended to increase lipoprotein lipase (LPL) activity, up-regulated CPT-1, angiopoietin-like protein 4 (Angpt14), LPL and triglyceride hydrolase (TGH) expression and down-regulated fatty acid synthetase (FAS), G protein-coupled receptor 41(GPR41) and GPR43 expression in the liver. L. delbrueckii addition increased adenosine monophosphate activated protein kinase (AMPK) expression in longissimus dorsi, upregulated LPL, CPT-1, Angptl4 and cluster of differentiation 36 (CD36) expression in subcutaneous fat, and enhanced LPL, CPT-1, TGH, adipocyte determination and differentiation-dependent factor 1 (ADD1) and hormone sensitive lipase (HSL) expression in leaf lard. These findings suggested that L. delbrueckii might enhance lipolysis and fatty acid β-oxidation to lower serum TG levels via colonic microbiota modulation and short chain fatty acids-mediated lipid metabolism of growing-finishing pigs.

肠道菌群及其代谢产物在宿主代谢过程中发挥关键作用。本团队前期研究发现，补充德氏乳杆菌（Lactobacillus delbrueckii）可影响猪的脂质代谢，但其潜在机制尚不明确。本研究旨在探究德氏乳杆菌对育肥猪结肠菌群组成、代谢产物、血清脂质与激素水平、各组织脂肪代谢相关酶活性及基因表达的影响。试验将12头猪随机分为两组（每组n=6），两组猪分别饲喂添加0.1%德氏乳杆菌的日粮（Con + LD）与基础日粮（Con），试验周期为28天。
试验结果显示，补充德氏乳杆菌后，猪血清中甘油三酯（triglyceride, TG）水平降低，游离脂肪酸（free fatty acid, FFA）含量升高，且结肠食糜中丁酸浓度增加。日粮添加德氏乳杆菌可提升结肠食糜中乳杆菌属（Lactobacillus）与丁酸弧菌属（Butyrivibri）的丰度，并对阿克曼菌属（Akkermansia）及巨球形菌属（Megasphaera）的丰度存在提升趋势。
饲喂德氏乳杆菌可上调结肠组织中胰高血糖素样肽1（glucagon-like peptide 1, GLP-1）、单羧酸转运蛋白1（MTC1）及钠依赖性单羧酸转运蛋白1（SMCT1）的基因表达。在肝脏组织中，饲喂德氏乳杆菌可提升脂蛋白脂酶（lipoprotein lipase, LPL）活性，上调肉碱棕榈酰转移酶1（CPT-1）、血管生成素样蛋白4（Angpt14）、LPL及甘油三酯水解酶（TGH）的基因表达，并下调脂肪酸合成酶（fatty acid synthetase, FAS）、G蛋白偶联受体41（GPR41）及GPR43的基因表达，同时对LPL活性存在提升趋势。
德氏乳杆菌添加可提升背最长肌中腺苷酸活化蛋白激酶（AMPK）的基因表达；上调皮下脂肪中LPL、CPT-1、血管生成素样蛋白4（Angptl4）及分化簇36（CD36）的基因表达；并增强猪板油组织中LPL、CPT-1、TGH、脂肪细胞定向和分化因子1（ADD1）及激素敏感性脂酶（HSL）的基因表达。
上述结果表明，德氏乳杆菌可能通过调控结肠菌群及短链脂肪酸介导的脂质代谢，增强育肥猪的脂肪分解与脂肪酸β-氧化过程，从而降低血清TG水平。