Semen analysis and fertility assessment in rabbits: statistical power and design considerations for toxicology studies.
Williams-J; Gladen-BC; Schrader-SM; Turner-TW; Phelps-JL; Chapin-RE
Fundam Appl Toxicol 1990 Nov; 15(4):651-665
The within and between rabbit variability for various parameters analyzed in semen were determined. The endpoints chosen were based on their origin within the male reproductive tract and can therefore be considered as potential functional markers for such sites. An attempt was made to determine the minimum number of sperm required for normal fertility in the New-Zealand-white-rabbit. Sperm concentration and total number were among the most variable parameters analyzed in rabbit semen. The results demonstrated that collecting four ejaculates/male once a week was the least variable of the collection frequencies evaluated. The inclusion of a preexposure period into the study design increased the statistical power for all semen parameters. In assessing a toxic insult on spermatogenesis in the rabbit via semen analysis, a treatment/post treatment period of 9 to 10 weeks is the minimum time that should be considered. The overall variability of a study is comprised of biological and analytical variation, and the latter should be reduced as much as possible. The results showed that one million motile sperm can be considered the minimum number for normal reproductive capacity of the New-Zealand-white-rabbit.
NIOSH-Author; Reproductive-system; Reproductive-effects; Laboratory-animals; Spermatozoa; Cytotoxic-effects; Reproductive-hazards; Comparative-toxicology
Fundamental and Applied Toxicology