Correlations Between Antioxidant Enzymes Activity and Lipids Peroxidation Level in Blood and Milk from Cows with Subclinical Mastitis

Abstract. The aim of this study was the evaluation of enzymatic antioxidant status (catalase, superoxid dismutase) and lipids peroxidation level in blood and milk collected from cows with subclinical mastitis in comparison with healthy cows. The following tests were carried out on the 84 lactating cows, 10 of them having a positive diagnosis, representing 12 % of the total lactating cows. For these 10 cows positive the diagnosis was confirmed by the increased number of somatic cells present in milk. Increasing number of somatic cells in milk affected the activity of antioxidant enzymes studied different. SOD activity does not change significantly in mastitic milk. The average values obtained were between 1.044±0,17 U/ml at milk from healthy cows and 1.066±0,15 U/ml for the mastitis milk. In the case of catalase activity were observed significant variations between normal and mastitis milk. Values obtained in mastitis milk had a higher average 2.09±0.42U/ml, compared to normal where the average was 1.21±0.35U/ml. Increased activity of antioxidant enzymes in milk were correlated with changes in activity of these enzymes in the blood. Thus, SOD activity in blood from healthy cows had mean values of 1688.4±165.48U/g Hb while in cows with mastitis mean values were 1764.5±110.46U/g Hb. For catase activity, the mean values were 1.46±0,32 U/g Hb in normal blood, while in blood from cows with subclinical mastitis were 2.05±0.17U/g Hb. In milk samples was noted that an increased level of somatic cells can be correlated with an increase in the concentration of MDA, so with increased lipid peroxidation processes