| dc.description.abstract | The aim of this study was to determine the serum oxidative status, antioxidant capacity, and oxidative stress index, as well as aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatinine profiles, of dairy cows fed rumen-protected choline during the transition period. A total of thirty dairy cows allotted to one control and two experimental groups (10 animals per group) were fattened from 3 weeks prior to the expected calving date until 3 weeks postpartum. The control group was fed a basal diet, and treatment groups 1 and 2, were fed a basal diet containing 60 g/head/day and 120 g/head/day or rumen-protected choline, respectively. Serum total antioxidant status (TAS) levels for the control group and treatment groups 1 and 2 at the time of parturition were 0.56 ± 0.029ab, 0.45 ± 0.028b, and 0.59 ± 0.036a, respectively. The differences between the groups were statistically significant (P < 0.05). Rumen-protected choline supplementation did not have a significant effect on TAS levels in the third week before parturition and in the first and third weeks of lactation. There were no significant differences (P> 0.05) between the groups in terms of total oxidative status (TOS), oxidative stress index (OSI) or creatinine levels. Serum ALT levels were significantly different (P < 0.05) between the groups at parturition and in the first week of lactation, but not significant (P > 0.05) for the other periods. In addition, the serum AST level was significantly different (P < 0.05) between the groups in the first and third weeks of lactation, but not significantly different (P > 0.05) for the other periods. After removing the effect of groups, time-dependent changes were significant (P < 0.001) for all parameters. The highest values for TAS, TOS and OSI were obtained in the third week before parturition. The values for these parameters decreased during parturition and after the postnatal period. The lowest values for serum ALT and creatinine occurred at parturition. Rumen-protected choline supplementation did not have a significant effect on serum TAS and TOS levels during the transition period. There is a need for further studies of animals with known metabolic profiles, malnourished animals, and those with high milk yields or metabolic disorders. | en_US |
