Effect of exogenous progesterone treatment on ovarian steroid hormones and oxidant and antioxidant biomarkers during peak and low breeding seasons in dromedary she-camel

BACKGROUND: Research about the effects of progesterone (P(4)) and the relationship of P(4) to oxidative stress has been achieved in ruminants but not enough in camels. AIM: This study evaluated the effect of exogenous P(4) hormone using CIDR for 7 days on blood concentrations of steroid hormones and oxidative status of dromedary she-camels during peak and low breeding seasons. MATERIALS AND METHODS: The present work was conducted on ten dark dromedary she-camels which were synchronized using a controlled internal drug release (CIDR) for 7 days as a reproductive management tool during peak breeding (November-April) and low breeding season (May-October). The blood samples were collected each other day from CIDR insertion until the end of experiment 5 days after the removal of CIDR. Camels were examined for P(4), estradiol (E(2)), and testosterone (T) as well as malondialdehyde (MDA) as indicator of lipid peroxidation and nitric oxide, superoxide dismutase (SOD), and glutathione-S-transferase as antioxidant markers. RESULTS: Results revealed that P(4) was higher during peak breeding season than low breeding season. While the levels of P(4) increased during CIDR insertion and declined at CIDR removal and thereafter during breeding season, its concentrations declined after CIDR application during the non-breeding season. On the other hand, blood E(2) and testosterone levels decreased after CIDR insertion in both high and low breeding seasons with higher serum E(2) concentrations during the peak than the low breeding season. MDA concentrations and SOD activities were significantly (p<0.05) high on day 3 after CIDR insertion during the breeding and non-breeding seasons. During both the seasons, GSH levels decreased after CIDR removal in camels. However, MDA was lower during non-breeding season than high breeding season with no seasonal effect on SOD activity. CONCLUSION: Exogenous P(4) treatment through CIDR in dromedary camels could be more efficient during breeding season than non-breeding season, and effects on circulating oxidant/antioxidant biomarkers and their return to normal levels might refer to the adaptation of camels to CIDR by modulating their oxidant and antioxidant levels.