Effect of different levels of dietary vitamin A on the embryonic mortality stage, steroidal hormone levels and reproductive organs in Japanese quail

It seems that vitamin A has a role in improving the reproductive performance of bird. The aim of this study was to investigate the dietary effect of five levels of 0, 4000, 8000, 16000 and 32000 IU/kg of vitamin A on ages of embryonic mortality, levels of steroidal hormones and reproductive organs of male and female Japanese quail. 320 adult Japanese quails were used in randomized complete block design with 5 treatments, 4 replicates and 16 birds per replicate with 12 of females and 4 males for 42 days. During experiment, birds had free access to water and feed and the lighting schedule or photoperiod was 16 hours of light. The embryonic death stage was not affected by treatments. In male quail, weight percentage of right testis was affected by experimental treatments. Weight percentage of right testis in the treatment containing 8000 IU/kg of vitamin was lower and the highest percentage was belong to 16000 IU/kg of vitamin A (P