Colorimetric and electrophoretic evaluation of lipoprotein fractions in healthy neonatal calves : comparison with results from adult cows and from calves with inflammatory conditions

High density lipoproteins (HDLs) are pivotal in innate immunity and decrease in serum during inflammation. Several studies have been done about lipoprotein changes in transition cows but little is known about their changes in newborn calves. The aim of this study is to provide information about HDLs in newborn calves, by defining the possible age-related changes in healthy calves compared with adults and by assessing the possible differences in calves with inflammation. Lipoprotein electrophoretic separation (reported as percentages) and colorimetric measurement of HDL (HDL-C) were performed on healthy cows and calves in order to identify possible differences in the lipoprotein profile due to the age. Then, age-matched calves with inflammatory conditions were also evaluated. Results showed that in calves HDL% and VLDL% were lower (mean values\ua0\ub1\ua0SD: 77.6%\ua0\ub1\ua08.6% and 2.6%\ua0\ub1\ua02.5%, respectively) and LDL% was higher (19.7%\ua0\ub1\ua07.4%) than in adults (89.0%\ua0\ub1\ua03.9%; 5.2\ua0\ub1\ua02.1% and 5.8%\ua0\ub1\ua03.1%, respectively). Sick calves revealed a decrease of both HDL% (mean values \ub1 SD: 61.0%\ua0\ub1\ua022.1%) and HDL-C (22.8\ua0\ub1\ua011.6\ua0mg/dL) and an increase of VLDL% (12.1% \ub1\ua013.1%) compared with controls (77.6%\ua0\ub1\ua08.6%; 41.5\ua0\ub1\ua011.2\ua0mg/dL and 2.6%\ua0\ub1\ua02.5%, respectively). Paraoxonase-1 activity, influenced by inflammation and oxidation, was measured, and it appeared correlated with HDL% and HDL-C in sick calves. In conclusion, this study revealed that HDLs concentration in healthy calves is lower than in adults, and further decreases in calves with inflammation, likely due to oxidation