Physiological antioxidative/oxidative status in bovine colostrum and mature milk

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. .