South African Journal of Animal Science
On-line version ISSN 2221-4062
Reports on the influence of dietary crude protein on male broiler breeder fertility are not consistent, and therefore an experiment was conducted to determine the effect of three isoenergetic diets containing 10.5%, 12.6% and 15% crude protein, respectively, on Ross broiler breeder male fertility from 26 to 41 weeks of age. Feed allocation was the same for each treatment, and was done according to breeder recommendations. Fertility was assessed by determining the number of sperm trapped in the outer perivitelline layer of eggs laid after artificial insemination with a fixed volume of semen collected from 12 males per treatment. Semen concentration, motility and morphology were also determined. Crude protein intake had a significant effect on the rate of decline in fertility post insemination. This resulted in a longer predicted length of the fertile period over all ages when eggs were fertilised with sperm obtained from males that received 12.6% CP diets (14.5 d) than males that received 10.5% and 15% CP (7 and 8.6 d respectively). There was, however, no treatment effect on the measures of live sperm with normal motility or morphology.
Keywords : Cockerel; insemination; perivitelline membrane; nutrition; reproduction.