The influence of season and age on the levels of lipids, lipoproteins and enzymes in the serum of Lička pramenka sheep

Abstract

This study aimed to identify seasonal and age related variability in triglycerides (TRI), paraoxonase (PON), stimulated PON (PON I) and cholesterol (CHOL, HDL, LDL) in extensively reared Lička pramenka sheep. The study was conducted 30 randomly chosen non-gravid Lička pramenka sheep on an extensive farm, grouped into three age groups in the Karlovac County, Croatia. Blood was collected by venepuncture of the jugular vein, twice in one year - the first sampling in spring (April) and the second in autumn (October). The results showed that age had no significant effect on any of the investigated indicators, while seasonality significantly affected five out of the six parameters examined. Significantly higher levels of serum lipid components in autumn can be explained by the influence of the traditional way of rearing and feeding Lička pramenka sheep. Furthermore, the results of PON I in all three age groups showed that the sheep are well adapted to the environment and to the rearing system. Future research should be carried out on higher number of farms, and should include more sheep in order to determine objective benchmarks for serum lipids and the enzymes connected to those lipids.