The present study aimed to investigate the effects of olive oil or nigella sativa oil as antioxidant dilutants on semen quality and hatchability upon semen storage at 5^oC. A 3x4 factorial experimental designs was performed including three dilutant sources {semen diluted 1: 1 with lake diluent (LD) sered as a control, semen diluted at 1ml semen: 1ml with LD and supplemented with olive oil or with nigella sativa oil   (1 ml/l00 ml of diluent), respectively} and four storage time (0, 24, 48 and 72 hours at5^oC). A total number of 60 cocks and 180 hens at 38-week-old were used to provide data on sperm assess and hatchability.

The obtained results show significant (P<0.01) increased sperm motility (%), and decreased dead spermatozoa (%), abnormal spermatozoa (%) and acrosomal damage (%) of cocks consequently, better hatchability rate of hens treated with diluted semen with nigella sativa oil (NSO) followed by olive oil (OO) compared to the control during different storage time (0, 24, 48 and 72 hours at of 5 ^oC). Percentage of sperm motility of cocks and hatchability rate of hens were decreased, while dead spermatozoa (%), spermatozoa abnormal (%) and acrosomal damage (%) of cocks were significantly (P<0.01) increased with the advancement of storage time. Therefore, Nigella sativa oil and olive oil could be used to improve the semen quality of cocks when stored at 5°C, up to72 hours, as well as hatchability rate of Mandarah laying hens.