Rumen-protected choline reduces hepatic lipidosis by increasing hepatic triacylglycerol-rich lipoprotein secretion in dairy cows

Objectives were to determine the effects of supplementing rumen-protected choline (RPC) on hepatic composition and secretion triacylglycerol-rich lipoprotein when cows subjected feed restriction develop fatty liver. It was hypothesized that RPC reduces triacylglycerol by enhancing lipoprotein. Pregnant, nonlactating parous Holstein (n = 33) at mean (±SD) 234 ± 2.2 d gestation blocked body condition (3.79 0.49) assigned receive 0 g/d (CON), 25.8 ion from a product containing 28.8% chloride (CC; treatment L25.8), or 60.0% CC (H25.8). Cows fed for ad libitum intake first 5 restricted 41% net energy lactation required maintenance pregnancy 6 13. Intake metabolizable methionine maintained 18 during supplying methionine. Hepatic tissue sampled 13 analyzed glycogen, mRNA expression investigated. On 14, not received 10% solution tyloxapol intravenously 120 mg/kg weight block hydrolysis triacylglycerols in very low density (VLDL). Blood sequentially 720 min concentration total cholesterol. Lymph h after infusion, concentrations acids, β-hydroxybutyrate, glucose, triacylglycerol, A sample serum collected assayed metabolome composition. The area under curve (AUC) VLDL cholesterol, cholesterol calculated. Orthogonal contrasts evaluated effect (CON vs. [1/2 L25.8 + 1/2 H25.8]) source (L25.8 H25.8). Least squares means standard errors are presented sequence as CON, L25.8, H25.8. During restriction, supplementation reduced (9.0 4.1 4.5 0.6%) increased glycogen contents (1.9 3.5 0.2%). Similarly, transcripts involved synthesis assembly lipoproteins (MTTP), cellular autophagy (ATG3), inflammation (TNFA), associated with mitochondrial oxidation acids (HADHA, MLYCD) stabilization lipid droplets (PLIN2). After infusion tyloxapol, AUC (21,741 32,323 28,699 3,706 mg/dL per minute) (4,348 6,465 5,740 741 but tended reduce lymph (16.7 13.8 11.9 1.9 mg/dL). Feeding increase 89 metabolites serum, adjusting false discovery, including 3 acylcarnitines, 1 AA-related metabolite, 11 bile ceramide, diacylglycerols, 2 dihydroceramides, glycerophospholipid, 64 compared CON. mediated promote lipotropic lipidosis dairy cows.