BackgroundParturition is supposed to be related to oxidative stress, not only for the mother, but also for the newborn. Moreover, it is not clear whether consecutive pregnancies, parturitions, and lactations are similar to each other in regards to intensity of metabolic processes or differ from each other. The aim of the study was to compare dynamic changes of antioxidative parameters in colostrum and milk of sows taken during 72 h postpartum from animals in consecutive lactations. Activities of glutathione peroxidase (GSH-Px), glutathione transferase (GSH-Tr), and superoxide dismutase (SOD), and amount of vitamin A and C were measured. Healthy pregnant animals were divided into 4 groups according to the assessed lactation: A -1st lactation (n = 10), B - 2nd and 3rd lactation (n = 7), C - 4th and 5th lactation (n = 11), D - 6th - 8th lactation (n = 8). The colostrum was sampled immediately after parturition and after 6, 12, 18 and 36 h while the milk was assessed at 72 h after parturition. Spectrophotometric methods were used for measurements.ResultsThe activity of antioxidative enzymes and the concentration of vitamin A increased with time postpartum. The concentration of vitamin C was the highest between the 18th and 36th h postpartum.ConclusionsDynamic changes in the values of antioxidant parameters measured during the study showed that sows milk provides the highest concentration of antioxidants in the 2nd and 3rd and 4th and 5th lactation giving the best defence against reactive oxygen species to newborns and mammary glands.

The aim of the study was to evaluate the profile of antioxidant parameters in ewes' colostrum and milk in relation to breed during 5 d post partum. Total antioxidant capacity (TAC) was analysed and the activity of the enzymic antioxidants, glutathione peroxidase (GSH-Px) and glutathione transferase (GSH-Tr), as well as the concentration of the non-enzymic antioxidants, vitamin C, vitamin A and beta-carotene, were measured. Samples were collected from healthy animals belonging to two ewe breeds: Berrichon du Cher (n=15) and Uhrusk (n=15) kept in the Podlasie Province (Poland). Colostrum was sampled directly after parturition, as well as after 12, 24 and 48 h later and milk was sampled 5 d after parturition. Colostrum and milk for the evaluation of all parameters except for vitamin A and beta-carotene were centrifuged, and the supernatant was used for further analysis. Spectrophotometric methods were used for biochemical measurements. The results showed dynamic changes of antioxidative parameters within the time period examined. TAC values and GSH-Px activity increased significantly during the experiment. GSH-Tr activity showed a similar tendency in Uhrusk ewes but an opposite relationship in Berrichon du Cher. Concentrations of examined vitamins followed the increasing trends noticed in the activities of antioxidative enzymes. Moreover, differences between breeds in the evaluated parameters were detected; these differences were not unequivocal however. The results are also a source of not previously published physiological antioxidant profile in colostrum and milk of ewes over the post-partum period.

As colostrum provides the initial substrate supply, of immunological compounds and antioxidants to the neonate, the aim of the present study was to determine the antioxidative/oxidative status of bovine colostrum and milk. Colostrum was collected from healthy dairy cows (n=15) immediately after parturition, 6, 18, 36 h and 7 days later. The total antioxidant capacity (TAC) expressed as µmol/g protein was determined spectrophotometrically at 532 nm based on the reduction of tri-pyridyl-s-triazine (TPTZ). The indirect analysis of the intensity of lipid peroxidation - LPI, (expressed as µmol/g protein), corresponding to oxidation of peroxides, was measured spectrophotometrically at 505 nm. The TAC values have gradually increased from the 6th hour to day 7 (36h vs. 0h and day 7 vs. 0h; p<0.01) and were maximal in mature milk (day 7) (day 7 vs. 36h; p<0.05) whereas LPI values slightly fluctuated within the same period reaching maximal values at 36h (36h vs. 0h, 6h, 18h; p<0.05). In parallel, the ratio TAC/LPI has progressively increased from 71.6 (0h) to 177.6 (day 7). No overall positive correlation between TAC and LPI values was evidenced during the studied period. These results demonstrate dynamic changes of antioxidant systems while LPI remained stable, providing efficient neutralization of radical oxygen species.