Adsa Logo White Adsa Title White

A high rumen degradable starch diet modulates jejunum microbiota and alters enterohepatic circulation of bile acids in dairy goats.

Y. Cao

Events

06-22-2020

Abstract:

115
A high rumen degradable starch diet modulates jejunum microbiota and alters enterohepatic circulation of bile acids in dairy goats.
J. Shen1, X. Chen2, L. Wang1,2, J. Yao1, Y. Cao*1,2. 1Northwest A&F University Yangling, Shaanxi, China, 2Harvard Medical School Boston, MA.

The aim of this study was to investigate the mechanism of milk fat depression in the liver and small intestine of dairy goats fed different rumen degradable starch (RDS) diets. Eighteen Guanzhong lactating goats (2nd lactation, 45.8 � 1.54 kg) in experiment 1 and 6 ruminally cannulated dairy goats (aged 2—3 y, 54 � 2.4 kg) in experiment 2 were used to investigate the effect of dietary RDS content (LRDS = 20.52%, MRDS = 22.15%, HRDS = 24.88%) on liver metabolism and free-LPS concentrations, respectively. The treatments lasted for 28 d with 21 d for adaption and 7 d for sampling. In experiment 1, blood samples were collected for analyses of biochemical parameters; liver, ileal mucosa, and jejunal contents samples were collected for analysis of metabolites, mRNA expression and microbiota, respectively. In experiment 2, rumen fluid and blood samples were collected for determination of free-LPS. Comparisons were made between the treatments using Student's t-test. Free-LPS concentrations were analyzed using the MIXED procedure of SAS. Compared with LRDS, the HRDS significantly decreased the milk fat composition (3.74% to 3.01%), enhanced the activity of alkaline phosphatase and aspartate aminotransferase in plasma, increased free-LPS concentrations in both rumen liquid (7570 EU/mL to13600 EU/mL) and plasma (0.037 EU/mL to 0.179 EU/mL) (P < 0.05), indicating hepatic injury were induced by HRDS. HRDS significantly decreased the concentrations of certain fatty acids (included linolenic acid, etc.), and phospholipids (including PC (18:0/18:1), etc.), and increased the concentrations of L-carnitine and L-palmitoylcarnitine (VIP > 1, P < 0.10), and the protein expression of carnitine palmitoyltransferase-1 (P < 0.05) in liver compared with the LRDS, indicating HRDS promoted lipid β-oxidation. Compared with LRDS, HRDS significantly increased the relative abundance of Firmicutes and Ruminococcus_2 in jejunal content (P < 0.05, LDA > 2), increased the concentrations of taurochenodeoxycholate and taurodeoxycholic acid (VIP > 1, P < 0.10) and mRNA expression of CYP7A1 (P < 0.05) in liver, decreased the expression of bile acid receptor FXR (P < 0.05) in ileum mucosa, indicating the negative feedback regulation of bile acid synthesis was inhibited. This study demonstrated that HRDS feeding modulates jejunum microbiota and alters enterohepatic circulation of bile acids, and promotes lipid β-oxidation in dairy goats.

Keywords: bile acids, enterohepatic circulation, lipid metabolism.

Biography: