Evaluation of Fertility Response and Transient Sterility Following N-Ethyl-N-Nitrosourea Exposure in Male Japanese Quails
Abdulhakeem T. Hassan-Okoh
Department of Animal Production, Faculty of Agriculture, University of Ilorin, Ilorin, Nigeria.
Ayokunle A. Toye *
Department of Animal Production, Faculty of Agriculture, University of Ilorin, Ilorin, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
In Nigeria, Japanese quail production faces significant challenges due to the bird’s small size, which results in low meat yield and limited consumer acceptance. These constraints highlight the need for genomic improvement strategies aimed at enhancing economically important traits such as body size. As an initial step toward genomic improvement, this study investigated whether administering N-ethyl-N-nitrosourea (ENU) as a chemical mutagen could induce transient sterility in male Japanese quails—a critical marker of successful germline mutagenesis. A total of ninety male Japanese quails were randomly assigned to one of three groups for this study: an ENU treatment group, a sham shock solution control group, and a normal saline control group. Each group received its respective treatment solution via intraperitoneal injection, with dosages adjusted according to individual body weights and administered once a week for three consecutive weeks. Fertility and semen quality parameters were evaluated both before and after the treatments. Specifically, the ENU-treated cocks were injected with a total dose of 300 mg ENU per kilogram of body weight, delivered in three weekly fractions of 100 mg ENU/kg. Fertility in ENU-treated cocks decreased significantly during weeks 1, 2, and 3 post-treatment, but no significant differences were observed from weeks 4 to 6. Although there was an early decline in fertility, transient sterility was not induced, as fertility remained relatively high. Semen quality parameters showed no statistically significant differences between ENU-treated and control cocks. The study concludes that the dosage regimen was insufficient to induce transient sterility in Japanese quail cocks, suggesting that species-specific reproductive physiology, particularly the rapid spermatogenic cycle of Japanese quail, may restrict the mutagen’s effectiveness. To address these limitations, future research should explore alternative dosing strategies that account for the species-specific characteristics of Japanese quails.
Keywords: N-ethyl-N-nitrosourea, Japanese quail, transient sterility, semen, fertility, mutagenesis