Thermoregulatory response and oxidative stress indices of rabbit bucks administered ascorbic acid and sodium bicarbonate in a humid tropical environment

Abstract

Abstract Background This study aimed to assess the effect of ascorbic acid and sodium bicarbonate on thermoregulatory response and oxidative stress markers of rabbit bucks during highest temperature-humidity index in a humid tropical environment as a mitigation strategy against impact of high ambient temperature on the animals. Twenty-eight exotic rabbit bucks of 9 months old weighing 2.54 ± 0.23 kg were randomly allotted to four treatments consisting of T1 (Control-2 ml of sterile water), T2 (2 ml of 300 ppm ascorbic acid), T3 (2 ml of 0.30% sodium bicarbonate) and T4 (2 ml mixture of 150 ppm ascorbic acid + 0.15% sodium bicarbonate, administered orally at 48 h interval for 12 weeks. After a month of administration, rectal temperature, ear temperature, respiratory rate and pulse rate were monitored twice daily (8:00 am and 4:00 pm). Semen samples were collected from all bucks weekly for seminal lipid peroxidation and total antioxidant activity assay. Blood samples were collected from all bucks and serum obtained using standard procedure to assay for lipid peroxidation and total antioxidant activity. Results The result revealed that the rabbits were exposed to very severe heat stress for greater part of the day. At week 5, bucks on T2, T3 and T4 had increased respiratory rate at 8 am than those on T1, similar trend was observed at week 4 and 6. At 4 pm, the pulse rate was significantly (p < 0.05) different among the treatments at weeks 11, bucks on T2, T3 and T4 had significantly lowered (p < 0.05) pulse rate than those on T1. The administration of ascorbic acid, sodium bicarbonate and its combination did not significantly (p > 0.05) influence the ear and rectal temperature of the bucks. At week 11, seminal total antioxidant activity of bucks on T1, T2 and T3 was significantly (p < 0.05) lower than bucks on control T4. Lipid peroxidation level was significantly (p < 0.05) lower in bucks on T2, T3 and T4 than those bucks on the control. Conclusion The administration of ascorbic acid, sodium bicarbonate and its combination had enhanced seminal total antioxidant and reduced lipid peroxidation in heat-stressed bucks.