The relationships of glucose-6-phosphate dehydrogenase, glutathione peroxidase, nicotinamide adenine dinucleotide phosphate and glutathione with milk quality parameters

In this study, it was aimed to determine the relationship between with G6PD, GPx, NADPH, rGSH and milk yield and milk quality, to evaluate the effect of these parameters on milk quality, in Holstein cattle. Milk samples were collected from 20 healthy Holstein cattle. Milk yield was obtained from routine farm datum. The analyses of milk fat %, protein %, lactose %, non-fat dry matter %, urea % and casein % were held by "milk components measuring instrument", and G6PD and GPx activities in milk cell supernatants along with NADPH, rGSH and the total protein levels were assessed by spectrophotometric methods. Milk lactose levels (%) were negatively correlated with milk cell G6PD activity (r=-0.574, P<0.05) and NADPH levels (r=-0.485, P<0.05). Milk cell G6PD activity (r=0.708, P<0.01) and milk cell NADPH levels (r=0.609, P<0.01) were positively correlated with somatic cell count. A positive correlation (r=0.630, P<0.01) was determined between the somatic cell count and milk cell NADPH levels. In conclusion, there was no correlation between milk yield and milk quality parameters with the related parameters, except for lactose levels, in healthy cattle milk. It is suggested to investigate the relationship between lactose and G6PD with further studies.