effect of melatonin and vitamin e on frozen semen characteristics of fars indigenous roosters

seventy four 9-month-old fars indigenous roosters were randomly divided into three equal groups. the first group was exposed to 14 hours light and 10 hours darkness. the second group was exposed to the same lighting schedule as the first one and supplemented with 3 mg/kg of body weight edible melatonin daily. the third group was finally exposed to 24 hours of constant light. semen was collected four times at 20 day intervals through abdominal massage the semen samples of every 8 roosters in each group, being pooled. the pooled semen samples of the first group were supplemented with either 4 vs. 8 mg/ml of vitamin e or 3 vs. 6 mm of melatonin, respectively. the pooled semen samples were frozen, and then thawed after 2 weeks past. semen characteristics including ph, sperm motility, sperm viability, sperm membrane integrity and malondialdehyde (mda) concentration were evaluated before freeze and after thawing. the interaction between the treatment and freezing process was significant (p