Key enzimes and nuclear receptors of hepatic lipid metabolism in dairy cattle during the transition period

ANGELI E.; TRIONFINI V.; GAREIS N.; MARELLI B.; HEIN G.; ORTEGA H.

Mar del Plata

Congreso; LXIV Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2016

Sociedad Argentina de Investigación Clínica

The transition period (TP) is the most critical in the lactation ofa dairy cow, characterized by a negative energy balance leadingto an important lipid mobilization, with increases in the systemicnon-esterified fatty acids (NEFA) and beta-hydroxybutyric (BHB)concentrations. While carnitine palmitoyltransferase-1 (CPT1),acyl-Coa oxidase-1 (ACOX1) and the nuclear receptor PPARalphapromotes fatty acids oxidation in several tissues, includingthe liver, diacylglycerol acyltransferase-1 (DGAT1) is involved intriacylglycerol biosynthesis. The aim of this study was to evaluatesome pathways of hepatic lipid metabolism during the TP. Bloodsamples and liver biopsies from dairy cattle (n = 10) were takenat 28 and 14 days prepartum, and also at 4, 14, 28 and 60 dayspostpartum. Systemic NEFA, BHB, glucose and insulin concentrationswere measured. Besides, the liver expressions of fatty ac idsoxidation (CPT1, ACOX1) and re-esterification (DGAT1) enzymes,and nuclear receptor PPAR-alpha were evaluated by Real Time-PCR and western blot. There were no significant changes (p >0.05) in glycemia and insulinemia. Differences in the BHB andNEFA concentrations were observed at different sampling days,being significant at 4, 14 and 30 days postpartum (p < 0.05). Theexpressions of CPT1 and PPAR-alpha were higher in the postpartumperiod (p < 0.05), with an opposite behavior respect theexpression of DGAT1. No differences in the mRNA expression ofACOX1 were observed (p > 0.05). These results show significantchanges in hepatic lipid metabolism of dairy cows during the TP.These knowledge could represent a useful tool to understand themetabolic behavior in animals with different milk production andto optimize the health of dairy cattle during this period.