Effects of body condition scorein liver insulin-signaling of dairy cattle during the transition period.

ANGELI, E.; REY, F.; ORTEGA, H.H; HEIN, G.J.

Bolonia

Congreso; 50th National Congress of the Italian Association for Buiatrics; 2018

Società Italiana di Buiatria

The transition period (TP) is the most critical stage in the lactation of a dairy cow, characterized by an increase of plasma non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) with low glucose concentration. Previous studies have descripted the presence of insulin resistance during peripartum [1]. The aim of this study was to evaluate the insulin-signaling pathway and some plasma parameters during the TP in the in cows with different body score condition (BSC).Sixteen grazing dairy cows, belonging to a commercial dairy farm, were classified using the 5-point scale [2] as high BCS (HBCS, ≥ 3.5, n = 8,) and low BCS (LBCS, < 3.5, n = 8). Blood and liver biopsies were sampled at -14, 4, 14 and 28 days relative to parturation. The concentrations of NEFA, BHB, glucose, triglycerides, insulin and liver triglycerides were spectrophotometrically measured. Also, the liver protein expression of relevant insulin signaling components: insulin receptor (IR), insulin receptor substrate 1 (IRS-1), protein kinase B (Akt) and phosphorylated protein kinase B (p-Akt), was measured by western blot.Cows in HBCS had higher NEFA concentration than LBCS (p < 0.05). In addition, we detected an interaction (BCS x time, p < 0.05) for glucose; concentration of this parameter increased at day 28 postpartum in HBCS group (p < 0.05). On the other hand, we also recorded an interaction (BCS x time, p < 0.05) for p-Akt; the protein expression was lower in HBCS than LBCS group at 28 days postpartum (p < 0.05). No differences were recorded in the other parameters (p > 0.05).These results suggest that an alteration in liver insulin-signaling from cows with HBCS could contribute to the augment of glycemia. Besides, a lower insulin sensitivity could be associated with higher NEFA concentrations [3]. This knowledge could represent a useful tool to understand the metabolic behavior to optimize the health and milk production of dairy cattle during this period.