Effect of exogenous melatonin and different photoperiods on oxidative status and antioxidant enzyme activity in Chhotanagpuri ewe

AIM: The present study was conducted to evaluate the effect of exogenous melatonin under different photoperiods on oxidative status in Chhotanagpuri ewe. MATERIALS AND METHODS: A total of 42 non-pregnant, non-lactating Chhotanagpuri ewe, having body weight ranging between 14.11±0.09 and 15.38±0.06 kg, were selected and were isolated from rams 2 months before melatonin administration. The selected animals were allocated randomly into seven groups, namely, Group I (normal control), Group II (long day [LD] control), Group III (LD+melatonin administration orally, 3 mg/day), Group IV (LD+melatonin administration subcutaneously, 1 mg/day), Group V (short day [SD] control), Group VI (SD+melatonin administration orally, 3 mg/day), and Group VII (SD+melatonin administration subcutaneously, 1 mg/day) comprising six animals in each group. Rams were then introduced into each group after completion of exogenous administration of melatonin. Blood samples with anticoagulant in vials were collected from each animal day before the start of the experiment and thereafter every month up to 5(th) month. Hemolysate was prepared for estimation of oxidative stress parameters such as malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT). RESULTS: It was observed that the level of MDA was significantly (p<0.05) higher in LD groups (Group II, III and IV) in comparison to control and SD groups (VI and VII) at 1(st) month. MDA concentration after exogenous administration of melatonin was significantly (p<0.05) decreased in Group IV and VI in comparison to 1(st) month. SOD was significantly (p<0.05) higher in SD groups (V, VI, and VII) at the 1(st) month in comparison to 0 day. After exogenous administration of melatonin, SOD concentration was significantly (p<0.05) higher in Groups III and IV in comparison to 1(st) month. CAT was significantly (p<0.05) higher in SD groups (V, VI, and VII) in comparison to control and LD groups. After exogenous administration of melatonin, CAT concentration was significantly (p<0.05) higher in Groups III, IV, VI, and VIII in comparison to Groups I, II, and V. At the 3(rd) month, CAT concentration significantly (p<0.05) decreased in Groups III, IV, VI, and VII in comparison to 2(nd) month of experiment. However, a decreasing trend of CAT was observed in all the groups from 3(rd) to 5(th) month. CONCLUSION: The present experiment revealed that exogenous melatonin was able to reduce significantly the level of MDA and increased the activity of SOD and CAT in Chhotanagpuri ewe.