Fatty liver in dairy cows post partum is associated with decreased concentration of plasma triacylglycerols and decreased activity of lipoprotein lipase in adipocytes

Abstract

Cholesterol and phospholipid concentrations in serum lipoproteins, plasma activities of lecithin:cholesterol acyltransferase (LCAT) and phospholipid transfer protein (PLTP) and lipoprotein lipase (LPL) activity in adipose tissue biopsies were measured ante and post partum in dairy cows given either free or restricted access to feed during the dry period. After parturition, all cows were fed ad libitum. The purpose of this study was to try to understand the earlier observed marked drop post partum in plasma triacylglycerol (TAG) in terms of lipoprotein metabolism in cows developing fatty liver post partum. As would be expected, free access to feed during the dry period induced a rise of hepatic TAG concentrations post partum associated with a decrease in plasma TAG levels. Total and free cholesterol concentrations in the VLDL, IDL, LDL and HDL2 fractions fell immediately after parturition. VLDL and IDL cholesterol concentrations remained at a constant, low level during the entire sampling period post partum, whereas the drop in LDL and HDL2 cholesterol post partum was followed by a rebound rise. Plasma LCAT and PLTP activities decreased by on average 19% and 33%, respectively, after parturition and then rose to values seen before parturition, but there was no effect of feeding regimen during the dry period. Activities of LCAT and PLTP were significantly correlated with cholesterol and phospholipid concentrations in LDL and HDL2. Plasma LCAT activity, as measured with exogenous substrate, and PLTP activity were both positively correlated with HDL3 phospholipid levels. LPL activity in adipose tissue dropped after parturition, the drop being smaller after feeding ad libitum during the dry period. It is concluded that the drop in adipose tissue LPL activity post partum is at variance with the simultaneous fall in plasma TAG. Possibly, the decrease in adipose tissue LPL activity helps to channel fatty acids away from adipose tissue into the udder. The post-partum changes in lipid transfer proteins in the blood are in line with the changes observed in the levels of the lipoproteins.

Serum paraoxonase 1 (PON1) activity and lipid metabolism parameters changes in different production cycle periods of Holstein-Friesian, Polish Red and Norwegian breeds

“…In ruminants hepatic estrification exceeds a slow rate of triglyceride export as very low density lipoproteins. Lipid accumulation in the liver might lead to liver failure and fatty liver development (Van der Top et al 2005). Cows have a slow, hepatic very low density lipoprotein (VLDL) secretion rate in comparison to nonrumiants, thus influencing triglyceride serum level, and therefore VLDL is proposed as the main (the most important) triglyceride carrier (Bauchart 1993).…”

“…Nascent HDL particles are formed by lipidation of apoA-1. The lower secretion of VLDL might stand for reduced LDL formation, by intravascular degradation process via intermediate-density lipoprotein (IDL) (Van der Top et al 2005).…”

Metabolic evaluation of dairy cows submitted to three different strategies to decrease the effects of negative energy balance in early postpartum

“…Cholesterol concentration is in between of the reference values for Holstein cows in Rio Grande do Sul (González 2000). Lower serum cholesterol concentrations in the ϐirst weeks postpartum have been related with fatty liver (Steen 2001, Van den Top et al 2005.…”

Valores de referência e influência dos fatores etários, sexuais e da gestação no lipidograma de bovinos da raça Holandesa, criados no Estado de São Paulo

“…A análise da literatura existente sobre a influência da gestação e lactação evidencia que a preocupação maior de diversos pesquisadores (ANDERSEN et al, 2005;BLUM et al, 1983;CHRISTIE, 1981;COSTA, 1991;DUNCAN et al, 1963;DYK, 1995;FAGLIARI et al, 1998;GUEORGUIEVA et al, 1997;HERDT, 1988;HERDT, 2000;KRONFELD et al, 1982;KWEON et al, 1985;KWEON et al, 1986;LACETERA et al, 2005;LEAT, 1967;LONG, 1953;MARQUES JÚNIOR et al, 1996;MAYNARD et al;1931;PEHRSON, 1971;PÖSÖ et al, 1994;RADLOFF et al, 1966;SANTOS, 1998;SHAIBLE, 1932;SCHWALM e SCHULTZ, 1976;SOUZA, 2005;VAN den TOP et al, 2005;VARMAN e SCHULTZ, 1968) foi em avaliar especificamente a influência da lactação sendo que não existem delineamentos experimentais que procurassem isolar esta influência daquelas decorrentes da gestação.…”

“…As possíveis influências que o puerpério exerce nos teores plasmáticos de glicose decorrentes à alta demanda de glicose primariamente para a síntese de lactose (BLUM et al, 1983;KAPPEL et al, 1984;SCHALM;SCHULTZ, 1976;VAZQUEZ-AÑON et al, 1994) den TOP et al, 2005). A diminuição da concentração de triglicérides no sangue no período pós-parto seria explicada pela baixa capacidade hepática em sintetizar e/ou secretar VLDL, e em virtude da entrada lenta e crônica de triglicérides neste órgão, determinaria provável desenvolvimento de esteatose hepática, comprometendo ainda mais o órgão e sua função (GRUFFAT et al, 1996, VAN DEN TOP et al, 2005.…”