Effect of Age on Nitric Oxide Level in Murrah Buffalo (Bubalus bubalis) Neonates

Immune system of calf is more susceptible to oxidative stress during neonatal period due to immature defense system against superoxide radicals. Nitric oxide (NO), a component of bactericidal mechanisms of phagocytic leukocytes, plays a pivotal role in cell-mediated immunity. Present research has addressed many NO-related aspects of neonatal adaptation in the postpartum period. The experiment was conducted on twenty Murrah buffaloes selected from NDRI herd. Approximately 15 ml blood was drawn in sterile heparinised vacutainer tubes from each calf born from these buffaloes, by jugular veni-puncture on day 0 (Before colostrum feeding), followed by day 1, 3, 7, 14, 21, 28, 42, 56, 70,  84,  98,  112 and 126 post birth at 6.00 AM in the morning. Plasma was aliquoted and analysed for total NO by modified Griess Reaction as described by Shoker and coworker. Plasma nitrate and nitrite levels were significantly elevated (P<0.01) at birth in buffalo calves and decreased rapidly within first week of life with mean values decreasing more than 80%. The mean values declined from 797.08±43.62 µM/L (Precolostral levels) to 78.97±68.97 µM/L on day 126 post-birth. The levels afterwards though less than day 7 but were not comparable to mature buffaloes (1.09±0.41 µM/L to 7.63±2.75 µM/L) even after 126 days post birth exhibiting fluctuations in between. Therefore, we can say that buffalo neonates have an immature immune system as compared to the adult. Leukocytes from neonates produce unusually high concentrations of NO when compared with those produced by adult buffalo, thus, buffalo neonates have an immature immune system. Therefore, further research is needed in this aspect to explore the possibility of nitric oxide involvement in the extra-uterine adjustment of buffalo neonate.