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.

Tissues, Metabolic Pathways and Genes of Key Importance in Lactating Dairy Cattle

“…The remaining free fatty acids will be re-esterified to triglycerides (TG) and exported as VLDL to the plasma (Fig. 1) [50,74]. Van den Top et al [150] and Kessler et al [74] showed that plasma VLDL-cholesterol, LPL- [150].…”

“…Kessler et al [74] showed that there is a significant correlation between SREBF2 mRNA expression and the hepatic gene expression of both 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and HMGCS1. In addition, several investigations showed that occurrence of fatty liver syndrome early in lactation is associated with cholesterol carrier lipoproteins such as VLDL [50,74]. Cholesterol is transported by high density lipoproteins (HDL) from peripheral tissues to the liver [74].…”

The Dietary Addition of Fish Oil or Sunflower Oil Plus Starch Differently Modulates the Lipid Classes in Plasma of Lactating Cows and Goats

“…Indeed, the lower availability of plasma TG could decrease the need for the migration of mammary LPL toward the basal membrane for uptake by MG and could increase the flow of LPL toward the apical membrane and milk in cows, in contrast to goats . In ruminants, the TG in the plasma lipids are mainly of intestinal rather than hepatic origin, even if the liver conserves some capacity to synthesize TG that are secreted in VLDL in mid‐lactation . Plasma TG concentration depends on the physiological state of the animals, being higher in dry‐pregnant than in lactating ruminants and being higher at the end of lactation than at the beginning .…”

Sütçü İneklerin Laktasyon Pikinde Kronik Topallığın Risk Faktörleri Olarak Süt Üretimi, Vücut Kondisyon Skoru ve Metabolik Parametreler

“…The cholesterol concentration indirectly reveals the ability of the liver to produce VLDLs (very low density lipoproteins) and decreased cholesterol and triglycerides are sign of fatty liver [30,31] . Gross et al [32] showed that change in lipid metabolic parameters during starvation is depends on lactation stage. During early lactation we have decrease of cholesterol and triglyceride concentration, but in later period concentration of this parameters increase during feed restriction.…”