Changes in lipid peroxidation, antioxidant and serum biochemistry parameters: A comparison between pregnant and...

This study aimed to compare the activities of the antioxidant enzymes glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT), as well as reduced glutathione (GSH), lipid peroxidation (MDA), and serum biochemistry parameters in pregnant (P+, n = 13) and non-pregnant (P-, n = 7) bitches in order to elucidate physiological changes in oxidative status associated with pregnancy. Ultrasonography controls were performed on days 25, 35, 45, and 55 in both groups; additionally, a final examination was conducted one day after parturition (PP1) in P+ or day 63 (d63) in P-. Blood samples were collected on day 12 post-ovulation and subsequently in parallel with each ultrasonographic evaluation. On day 55, GPx, SOD and CAT activities, as well as MDA levels were significantly higher in the P+ group compared with the P- group (p < 0.05; p < 0.01). No significant differences were found in GSH concentrations between P+ and P-. Across sampling days, no significant differences were detected in SOD and MDA levels within the P+ group or in GPx and MDA levels within the P- group. No significant correlations were detected between enzyme activities, lipid peroxidation, and antioxidant parameters. The findings indicate that oxidative stress and antioxidant defense mechanisms increase at different stages of normal canine pregnancy, reflecting a physiological adaptation that supports the maintenance of pregnancy.