EFFECTS OF MILK PRODUCTION IN LIVER LIPID METABOLISM OF DAIRY CATTLE DURING THE TRANSITION PERIOD

ANGELI E; GAREIS NC; TRIONFINI V; REY F; SALVETTI NR; ORTEGA HH; HEIN GJ

Buenos Aires

Congreso; LX Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2017

SAIC

Thetransition period (TP) represents a conflictive scenario for the lactation ofdairy cows, in which the liver attempts to fix the important fat mobilizationas a result of a negative energy balance. The aim of this study was to analyze theimpact of milk production in some hepatic lipid metabolism pathways of dairycattle during the TP. Blood samples and liver biopsies from cows (n=18) weretaken at 28 and 14 days prepartum and at 4, 14, 28 and 60 days postpartum. Theanimals were divided into high production (HP) group and low production (LP) groupconsidering the average of the dairy production up to 120 days. Plasmaticconcentrations of non-esterified fatty acids (NEFAs) and beta-hydroxybutyrate (BHB),aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), glucose, triglyceridesand insulin along with liver triglycerides (LT) content were measured. Moreover,the mRNA expression of carnitine palmitoyltransferase-1 (CPT1), acyl-CoAoxidase-1 (ACOX1) and diacylglycerol acyltransferase-1 (DGAT1) was determined byreal time-PCR, and the protein expression of ACOX1 and PPAR-a by western blotassays. The AST, GGT and insulin concentrations were similar in both groups(p>0.05). While the glycemia and triglyceridemia were lower (p<0.05), theconcentrations of BHB, NEFAs and LT content were higher at 4 and 14 dayspostpartum (p<0.05) in the HP group. Furthermore in this group, while themRNA expression of CPT1 and ACOX1 were higher along the postpartum period, the proteinexpression of PPAR-a was higher on day 60. Although the ACOX1 proteinexpression was similar in both groups, the HP group showed a tendency toincrease (p<0.076). The mRNA expression of DGAT1 was similar in both groups(p>0.05).Significant differences were registered in liver lipid metabolism accordingthe milk production. These results suggest that HP have a major capacity offatty acids oxidation trying to resolve the increased fat mobilization duringthe TP.