Dairy cows with
ketosis are characterized by high blood concentrations of
ketone bodies and hepatic
lipid metabolism disorder. The discrepancies in the abundance of
mRNA encoding a variety of hepatic candidate genes in varying degrees of ketotic cows represent specific responses of the liver to the challenge of
fatty acids and
ketone bodies. Importantly, the expression disorder of hepatic genes involved in lipid metabolism plays a promoting role in the onset and progression of
ketosis. Thus, the aim of this study was to investigate the expression patterns of genes involved in the hepatic
fatty acids uptake, transport, activation, β-oxidation, synthesis, and esterification in the cows with subclinical
ketosis (SCK) or clinical
ketosis (CK). Twenty-four cows were selected into control [n = 8, β-hydroxybutyrate (BHB) ≤0.6 mM], SCK (n = 8, 3.0 > BHB ≥ 1.2 mM), and CK (n = 8, BHB ≥3.0 mM) groups according to the blood BHB concentration and clinical symptoms. The accumulation of hepatic
lipid, as indicated by
triglycerides (TG) contents and
Oil Red O and
hematoxylin and
eosin staining, was pronouncedly exacerbated in the tCK group compared with the control and SCK groups. The hepatic
mRNA expression of
fatty acids transport and activation genes,
liver fatty acid-binding protein (FABP1) and
long-chain acyl-CoA synthetase 1 (ACSL1), were both significantly higher in the SCK and CK groups than in the control group. The expression levels of
peroxisome proliferator-activated receptor α (PPARA) and its target genes,
carnitine palmitoyltransferase 1A (CPT1A) and
carnitine palmitoyltransferase 2 (CPT2), were significantly elevated in the SCK group but reduced in the CK group compared with control group. Furthermore, the gene expression level of
sterol regulatory element-binding protein 1 (SREBP1) and the
protein expression level of
sterol regulatory element-binding protein 1c and its target genes
acetyl-CoA carboxylase 1 (ACC1),
fatty acid synthase (FAS), and
stearoyl-CoA desaturase-1 (SCD1) and TG synthesis genes
diacylglycerol acyltransferase 1 (DGAT1) and
diacylglycerol acyltransferase 2 (DGAT2) were significantly higher in the CK group relative to the control group. In short, the present data indicated that hepatic
fatty acids uptake, transport, and activation are significantly increased in cows with SCK and CK, hepatic
fatty acids β-oxidation is significantly increased in SCK cows but markedly decreased in CK cows, and hepatic
fatty acids and TG synthesis are significantly increased in CK cows, thereby inducing hepatic steatosis in CK cows.