Glucose-6-phosphate dehydrogenase, glutathione peroxidase, total glutatione and reduced nicotinamide adenine dinucleotide phosphate in milk cells of subclinical mastitic cows.

This study aimed to determine the levels of milk cell total protein (TP), reduced nicotinamide adenine dinucleotide phosphate (NADPH), total glutathione (tGSH), activities of glucose-6-phosphate dehydrogenase (G6PD) and glutathione peroxidase (GPx) in subclinical mastitic cows. Milk from each udder was collected and grouped by the California Mastitis Test. Then, a somatic cell count (SCC) was performed, and the groups were re-scored as control (5-87 × 103 cells), 1st group (154-381 × 103 cells), 2nd group (418-851 × 103 cells), 3rd group (914-1958 × 103 cells), and 4th group (2275-8528 × 103 cells). Milk cell TP, NADPH, tGSH levels, G6PD, and GPx activities were assessed. Microbiological diagnosis and aerobic mesophyle general organism (AMG, cfu/g) were also conducted. In mastitic milk, TP, NADPH, and tGSH levels, and G6PD and GPx activities were significantly reduced per cell (in samples of 106 cells). In addition, milk SCC was positively correlated with AMG (r=0.561, p⟨0.001), NADPH (r=0.380, p⟨0.01), TP (r=0.347, p⟨0.01) and G6PD (r=0.540, p⟨0.001). There was also positive correlation between NADPH (r=0.428, p⟨0.01), TP (r=0.638, p⟨0.001) and AMG. NADPH was positively correlated with TP (r=0.239, p⟨0.05), GPx (r=0.265, p⟨0.05) and G6PD (r=0.248, p=0.056). Total protein was positively correlated with tGSH (r=0.354, p⟨0.01) and G6PD (r=0.643, p⟨0.001). There was a negative correlation between tGSH and GPx activity (r=-0.306, p⟨0.05). The microbiological analysis showed the following ratio of pathogens: Coagulase-Negative Staphylococci 66.6%, Streptococcus spp 9.5%, Bacillus spp 9.5%, yeast 4.8%, and mixed infections 9.5%. As a conclusion, when evaluating the enzyme and oxidative stress parameters in milk, it is more suitable to assign values based on cell count rather than ml of milk. The linear correlation between the SCC and AMG, milk cell NADPH, TP and G6PD suggests that these parameters could be used as markers of mastitis.

Effects of curcumin and dithioerythritol on frozen-thawed bovine semen.

The aim of this study was to determine the effects of curcumin and dithioerythritol added into bull semen extender on sperm parameters, lipid peroxidation, total glutathione and antioxidant potential levels of bull spermatozoa following the freeze/thawing process. Twenty-seven ejaculates obtained from three bulls were included in the study. Each ejaculate that was splitted into five equal groups and diluted in a Tris-based extender containing curcumin (0.5 and 2 mM), dithioerythritol (0.5 and 2 mM) and no additive (control) was cooled to 5 °C and frozen in 0.25-ml French straws. The extender supplemented with 0.5 mMdose of curcumin led to lower percentage of total abnormality (20.40 ± 2.36%) when compared to the control (30.60 ± 1.47%, P < 0.05). Curcumin and dithioerythritol at 0.5 mM provided a greater protective effect in the membrane functional integrity (54.40 ± 2.09% and 50.00 ± 2.68%), in comparison with control (37.20 ± 1.77%, P < 0.001). Supplementation with antioxidants did not significantly affect the lipid peroxidation and antioxidant potential levels, while the maintenance of total glutathione levels in curcumin 0.5 mM was demonstrated to be higher than that of control, following the freeze/thawing (P < 0.05). Supplementation with these antioxidants prior to the cryopreservation process may be recommended to facilitate the enhancement of sperm cryopreservation techniques.