Postpartum nitric oxide, oxidants and antioxidants levels in ewes and their lambs

• Lambs and ewes respond differently during the postpartum period regarding their oxidant and antioxidant metabolism.
• Changes in oxidant and antioxidant status are related to the immune response and tissue lesions.
• Nitric oxide should participate in the immune response of sheep and lambs, and is increased in postpartum.

The aim of this study was to evaluate nitric oxide levels, oxidants and antioxidant levels in multiparous ewes with simple parturition and their respective newborns on an extensive rearing system. Blood samples were drawn from ewes (n = 30) and their respective lambs (n = 30) on days 1, 5, and 10 postpartum in order to measure nitrate/nitrite (NOx) seric levels, total oxidation status (TOS), total antioxidant capacity (TAC), and ferric reducing ability of plasma (FRAP) through biochemical techniques using an automatic analyzer. NOx levels in lambs are significantly increased on days 5 and 10 compared to day 1 postpartum (P < 0.05), reaching higher levels in lambs when compared to ewes (P < 0.05). The TOS postpartum levels did not differ in ewes (P > 0.05). In addition, TOS levels in lambs were higher (P < 0.05) than in their mothers at day 1 postpartum. The TAC levels in mothers and lambs did not differ between day 1 and 5 postpartum (P > 0.05), but the lambs showed a reduction on day 10 compared to their mothers on the same day (P < 0.05). The FRAP levels in ewes was higher on day 10 postpartum when compared to days 1 and 5 (P < 0.05). In lambs, the FRAP levels were not different (P > 0.05), but were superior to those measured in the mothers on days 1 and 5 postpartum (P < 0.05). Based on these results, we conclude that ewes and lambs respond differently to the nitric oxide, oxidant, and antioxidant metabolism at postpartum. These alterations are important for lamb survival and development.