Negative energy balance up‐regulate the levels of hepatokines in dairy cows during the peripartum period

Abstract

IntroductionThe periparturient period is vitally important to the health status and the reproductive performance of dairy cows. Negative energy balance (NEB) is considered as the pathological basis of energy metabolic disorders. Serum non‐esterified fatty acids (NEFA) and β‐hydroxybutyrate (BHBA) concentrations are the indicators of energy balance status. Angiopoietin‐like protein 4 (ANGPTL4) and fibroblast growth factor 21 (FGF21), known as hepatokines, play essential roles in lipid metabolism. However, in vivo the kinetics of ANGPTL4 and FGF21 are not entirely clear of dairy cows, particularly in dairy cows with ketosis and fatty liver. The purposes of this project were to evaluate the variations in serum concentrations of ANGPTL4 and FGF21 in periparturient dairy cows, and to examine the correlations between serum NEFA, BHBA concentrations and ANGPTL4, FGF21 concentrations, respectively, in the serum of experimental cows. Moreover, the serum concentrations of hepatokines from cows with spontaneous ketosis and fatty liver, and healthy cows were compared.MethodsExperiment IBlood parameters were measured in healthy periparturient Holstein cows from 4 wk antepartum to 4 wk postpartum (n=219). In this experiment, weekly blood samples were obtained from 4 wk before the expected calving date to 4 wk after calving.Experiment IIBlood parameters were measured in healthy cows (n=30), cows with ketosis (n=29) and fatty liver (n=25) within the first 4 wk of lactation. In this present study, all blood samples were collected from the coccygeal vein in the early morning before feeding.ResultsSerum concentrations of ANGPTL4 and FGF21 peaked at parturition, and declined rapidly over the following 2 wk. Serum ANGPTL4 and FGF21 concentrations were positively correlated with serum NEFA concentration (ANGPTL4 and NEFA: r=0.856, P=003; FGF21 and NEFA: r=0.848, P=0.004). However, the correlations between serum BHBA concentration and the serum concentrations of ANGPTL4 and FGF21 were not observed in experimental cows. Cows with ketosis and fatty liver had significantly higher serum concentrations of ANGPTL4 and FGF21 when compared with healthy cows (P<0.01).ConclusionSerum concentrations of ANGPTL4 and FGF21 were elevated during peripartum period in dairy cows, demonstrating that the energy balance changes that were associated with parturition contributed significantly to these effects. We propose that blood ANGPTL4 and FGF21 concentrations could be used as supplementary biomarkers of “energy balance” status in postpartum dairy cows. Although FGF21 and ANGPTL4 could play important roles in the adaptation of energy metabolism, they may be involved in the pathological processes of energy metabolism disorders of dairy cows in the peripartum period.Support or Funding InformationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.