title: Response of the cholesterol metabolism to a negative energy balance in dairy cows depends on the lactational stage.
abstract: The response of cholesterol metabolism to a negative energy balance (NEB) induced by feed restriction for 3 weeks starting at 100 days in milk (DIM) compared to the physiologically occurring NEB in week 1 postpartum (p.p.) was investigated in 50 dairy cows (25 control (CON) and 25 feed-restricted (RES)). Blood samples, liver biopsies and milk samples were taken in week 1 p.p., and in weeks 0 and 3 of feed restriction. Plasma concentrations of total cholesterol (C), phospholipids (PL), triglycerides (TAG), very low density lipoprotein-cholesterol (VLDL-C) and low density lipoprotein-cholesterol (LDL-C) increased in RES cows from week 0 to 3 during feed restriction and were higher in week 3 compared to CON cows. In contrast, during the physiologically occurring NEB in week 1 p.p., C, PL, TAG and lipoprotein concentrations were at a minimum. Plasma phospholipid transfer protein (PLTP) and lecithin:cholesterol acyltransferase (LCAT) activities did not differ between week 0 and 3 for both groups, whereas during NEB in week 1 p.p. PLTP activity was increased and LCAT activity was decreased. Milk C concentration was not affected by feed restriction in both groups, whereas milk C mass was decreased in week 3 for RES cows. In comparison, C concentration and mass in milk were elevated in week 1 p.p. Hepatic mRNA abundance of sterol regulatory element-binding factor-2 (SREBF-2), 3-hydroxy-3-methylglutaryl-coenzyme A synthase 1 (HMGCS1), 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), and ATP-binding cassette transporter (ABCA1) were similar in CON and RES cows during feed restriction, but were upregulated during NEB in week 1 p.p. compared to the non-lactating stage without a NEB. In conclusion, cholesterol metabolism in dairy cows is affected by nutrient and energy deficiency depending on the stage of lactation.
authors.affiliation: Veterinary Physiology, Vetsuisse Faculty University of Bern, Bern, Switzerland.
authors.forename: Josef J
authors.initials: JJ
authors.lastname: Gross
authors.affiliation: Veterinary Physiology, Vetsuisse Faculty University of Bern, Bern, Switzerland.
authors.forename: Evelyne C
authors.initials: EC
authors.lastname: Kessler
authors.affiliation: Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland; Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland.
authors.forename: Christiane
authors.initials: C
authors.lastname: Albrecht
authors.affiliation: Veterinary Physiology, Vetsuisse Faculty University of Bern, Bern, Switzerland.
authors.forename: Rupert M
authors.initials: RM
authors.lastname: Bruckmaier
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D002417:Cattle; D002784:Cholesterol / Q000235:genetics / Q000378:metabolism*; D003612:Dairying; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D007774:Lactation / Q000378:metabolism*; D008055:Lipids / Q000097:blood; D008099:Liver / Q000378:metabolism / Q000502:physiology; D008892:Milk / Q000378:metabolism*; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000378:metabolism; D014280:Triglycerides / Q000097:blood
chemical_list: D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase