Correlation Between Mastitis Pathogenic Bacteria and Glutathione Peroxidase Activity in Cows Milk

Abstract

Antioxidant activity of milk is due to the presence of antioxidant anzymes such as catalase, lactoperoxidase, glutathione-peroxidase, xanthin/oxidase, or vitamins and provitamins such as retinoils and carotenoids, tocopherols and ascorbic acid. The aim of this study was to establish a correlation between pathogenic bacteria type involved in cows mastitis and glutathione-peroxidase activity in milk. Determination of the enzyme activity was performed on milk samples, before and after germs inoculation with various dilutions of Streptoccocus spp., Staphylococcus spp. Pseudomonas spp. Escherichia spp. Candida spp. To show the glutathione-peroxidase activity during milk bacteria multiplication, an in vitro protocol for germs development in liquid medium (Muller Hinton agar with milk) was performed. Glutathione peroxidase activity in milk samples was performed on skimmed milk, using a commercial kit (Ransel, Randox Laboratories) and semiautomatic biochemistry analyzer MasterPlus Screen. We observe the fact that development of the pathogenic bacteria in milk is accompanied by a significant increase of glutathione-peroxidase activity. The level of enzyme activity depends on the type of bacteria. The highest values were in milk samples inoculated with Escherichia coli, values that exceeded 10 times the values of normal milk samples. For Streptococcus viridians, Pseudomonas aeruginosa and Candida spp. were established modest results, the lowest values being registered from samples containing Staphylococcus aureus.