Changes in the spermatogenesis and plasma concentrations of testosterone in growing guinea fowls

• Published in: Japanese poultry science Vol. 26; no. 5; pp. 326 - 330
• Main Authors: OGAWA, Hiroshi, KUWAYAMA, Takehito, ICHINOE, Kenji
• Format: Journal Article
• Language: Japanese; English
• Published: Japan Poultry Science Association 1989
• Subjects: blood plasma; espermatogenesis; gallina de guinea; guinea fowl; madurez sexual; maturite sexuelle; peso; pintade; plasma sanguin; plasma sanguineo; poids; sexual maturity; spermatogenese; spermatogenesis; testes; testicule; testiculos; testosteronas; testosterone; weight
• ISSN: 0029-0254
• DOI: 10.2141/jpsa.26.326

The present study was conducted to evaluate the process of sexual maturation in male guinea fowls. The birds were reared under a daily lighting schedule of 14 hours light (05:00 to 19:00) and 10 hours darkness. The body weight, testicular weight, diameter of seminiferous tubules and plasma concentrations of testosterone were measured at 0, 4, 8, 12, 14, 16, 18, 20, 24, 28 weeks of age. Left testes of the birds were classified into six stages of spermatogenesis by histological assessment. The following results were obtained. 1. The body weight, testicular weight, and diameter of the seminiferous tubules increased significantly (p<0.01 or p<0.05) up to 12 (body weight) and 14 weeks of age, respectively. Thereafter the body weight and diameter of seminiferous tubules continued to increase with age to maximum values (body weight: 2,012+-33.2g; mean+-S.E.M., diameter of seminiferous tubules: 355.2+-13.6 mu-meter; mean+-S.E.M.) till 28 weeks of age, while the testicular weight showed a maximum value (2.202+-0.086g; mean+-S.E.M.) at 24 weeks of age. 2. Stage of spermatogenesis of the testes advanced between 4 and 16 weeks of age, and spermatogenesis was completed after 16 weeks of age in all birds. 3. The plasma concentration of testosterone stayed below 100 pg/ml till 12 weeks of age and rose to a maximum value (374+-129 pg/ml; mean+-S.E.M.) from 12 to 14 weeks of age. Thereafter the concentration decreased gradually till 20 weeks of age, but it was not stabilized after 20 weeks of age.