Fetuin-A dynamics in transition cows' plasma

Abstract

Around parturition and during early lactation, cows enter a state of negative energy balance (NEB) driven by the onset of lactation and a reduced dry matter intake. The major metabolic adaptation to NEB is adipose tissue lipolysis that releases nonesterified fatty acids (NEFA) into systemic circulation. High plasma NEFA predisposes cows to metabolic and inflammatory based diseases that negatively impact animal welfare and increase economic losses to dairy producers. However, not all cows with increased plasma NEFA concentrations develop a disease, thus underscoring the need for novel lipid mobilization-related biomarkers that could improve accuracy of disease prediction. In humans, high fetuin-A concentrations have been identified as an independent marker of insulin resistance and a predictor of type 2 diabetes and non-alcoholic fatty liver. Furthermore, elevated human fetuin-A concentrations are strongly associated with dyslipidemias. Fetuin-A is an abundant carrier of NEFA in plasma and is mainly expressed in hepatocytes, monocytes/macrophages, and adipocytes. Fetuin-A inhibits insulin receptor signaling and therefore increases lipolysis and NEFA efflux from adipose tissues. Despite its strong link with lipolytic processes, fetuin-A expression in plasma and its relationship with metabolic markers in transition cows remains poorly understood. The objective of this study was to evaluate the dynamics of serum fetuin-A and its association with NEFA during the transition period.