Fourteen rc mutant and fourteen normal male birds (Rhode Island Red suie) were employed in a study to determine the effects of rc mutation on semen characteristics, testosterone profile and spermatogenic tissues. Similar birds were randomly selected at 12 weeks of age and placed in 2 separate pens. The birds received similar diet and 16L: 8D light program during the experiment. Semen was collected during weeks 16 – 18 from each bird twice a week and evaluated for semen volume (SV), sperm concentration (SC), total sperm count (TSC), percent sperm motility (%SM), dead sperm (%DS), and sperm metabolic activity (SMA). To determine the testosterone concentration (TC) in plasma, blood was collected on week 12, 16 and 18. Collected testicular tissue was processed and evaluated for somniferous tubule diameter (STD), round spermatid number (RSN), percent-elongated sperm (%ES) and semineferous tubules length (STL). Body weight (BW), comb weight (CW) and testes weight (TW) were determined at the end of experiment (week 20). The SV, TSC, and SM percent were significantly higher in normal birds where as DS percent was significantly higher in blind birds (P<0.05). The SC did not differ significantly between the two groups but the value was higher in normal birds. The sperm metabolic activity in the first hour of collection did not differ significantly between the two groups but after 24 hours; the level of SMA in normal group was significantly increased (P<0.05). The level of TC did not differ significantly between the two genotype groups but normal birds had higher TC in all collections, except for the last one. The STD, RSN, ES percent and STL in control birds were higher as compared to blind birds but the differences were insignificant except for ES percent. The BW, CW and TW between the two groups did not differ significantly but the weights were higher in the normal group than in blind birds. Statistical analysis of semen characteristics, testosterone profile and histological factors indicate detrimental effects of rc mutation in prepubertal blind male birds due to a lack in light receiving.
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