Obesity-driven prepartal hepatic lipid accumulation in dairy cows is associated with increased CD36 and SREBP-1 expression

Res Vet Sci. 2016 Aug;107:16-19. doi: 10.1016/j.rvsc.2016.04.007. Epub 2016 Apr 30.

Abstract

We investigated the hypothesis that obesity in dairy cows enhanced expression of proteins involved in hepatic fatty acid uptake and metabolism. Sixteen Holstein-Friesian close-up cows were divided into 2 equal groups based on their body condition score (BCS) as optimal (3.25≤BCS≤3.5) and high (4.0≤BCS≤4.25). Intravenous glucose tolerance test (GTT) and liver biopsies were carried out at day 10 before calving. Blood samples were collected before (basal) and after glucose infusion, and glucose, insulin and non-esterified fatty acid (NEFA) levels were determined at each sample point. In addition, β-hydroxybutyrate and triglycerides levels were measured in the basal samples. The liver biopsies were analyzed for total lipid content and protein expression of insulin receptor beta (IRβ), fatty acid translocase (FAT/CD36) and sterol regulatory element-binding protein-1 (SREBP-1). Basal glucose and insulin were higher in high-BCS cows, which coincided with higher circulating triglycerides and hepatic lipid content. Clearance rate and AUC for NEFA during GTT were higher in optimal-BCS cows. The development of insulin resistance and fatty liver in obese cows was paralleled by increased hepatic expression of the IRβ, CD36 and SREBP-1. These results suggest that increased expression of hepatic CD36 and SREBP-1 is relevant in the obesity-driven lipid accumulation in the liver of dairy cows during late gestation.

Keywords: CD36; Dairy cows; Fatty liver; Sterol regulatory element-binding protein-1.

MeSH terms

  • 3-Hydroxybutyric Acid / blood
  • Animals
  • Blood Glucose / analysis
  • CD36 Antigens / genetics
  • CD36 Antigens / metabolism*
  • Cattle
  • Cattle Diseases / metabolism*
  • Fatty Acids / metabolism
  • Fatty Acids, Nonesterified / blood
  • Fatty Liver / etiology
  • Fatty Liver / metabolism
  • Fatty Liver / veterinary*
  • Female
  • Glucose / metabolism
  • Glucose Tolerance Test
  • Insulin / blood
  • Insulin Resistance
  • Lactation
  • Lipid Metabolism
  • Liver / metabolism*
  • Obesity / metabolism
  • Obesity / veterinary*
  • Pregnancy
  • Sterol Regulatory Element Binding Protein 1 / blood
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism*

Substances

  • Blood Glucose
  • CD36 Antigens
  • Fatty Acids
  • Fatty Acids, Nonesterified
  • Insulin
  • Sterol Regulatory Element Binding Protein 1
  • Glucose
  • 3-Hydroxybutyric Acid