The effect of crude protein and calcium intake on fertility of male broiler breeders.
Broiler parent stock are selected to ensure that good characteristics will be passed to the offspring but management of broiler breeder birds is different to that of broiler chickens. Feeding broiler breeders ad libitum can result in body weight-related consequences such as musculo-skeletal disorders and the inability to mate successfully during natural mating. There is an age-related decline in fertility observed in broiler breeder flocks after 40 weeks of age. Management techniques such as feed restriction and spiking have therefore been employed to prolong and maintain fertility of breeders with increasing age. Feeding a female ration to male broiler breeders may negatively affect reproductive efficiency. The possibility that excess nutrients supplied to male broiler breeders influence fertility cannot be ignored because male fertility has a significant impact on overall flock fertility. Because the female broiler breeder has a higher requirement of protein and calcium, the effects of these on fertility of males fed a female ration are worth considering. The objective of this experiment was therefore to assess the effects of feeding four different diets, keeping feed allocation constant to result in 2 levels of crude protein intake and 2 levels of calcium intake (HP: LC, LP: HC, HP: HC, LP: LC) on semen quality of male broiler breeders in the production phase. An increase in crude protein intake significantly increased (p<0.05) body weight of male broiler breeders after 41 weeks of age with birds fed HP: LC, LP: HC and LP: LC being significantly different to males fed HP: HC. There was a significant CP x Ca intake interaction on male broiler breeder bodyweight after 52 WOA. There was no significant effect of CP intake on sperm concentration and sperm mobility. Calcium intake significantly decreased sperm concentration at 42 and 60 WOA but had no effect on sperm mobility. There was no significant influence of CP intake on sperm concentration with age. There was no significant response in overall log number of inner perivitelline layer sperm holes and across all ages. Log number of IPVL sperm holes declined with age from 37-59 WOA with day 2 post artificial insemination having a higher number of IPVL sperm holes counted across all ages.