Correlation of Reproductive Histological Characteristics with Age, 5α-Reductase and Androgens in Arabi Rams (Ovis aries)

The aim of this study was to evaluate the correlation between histological features of the reproductive system and age, 5α-reductase-2 (5αR2), and androgenic hormone levels in Arabi rams. Thirty Arabi rams were used in three age groups: lambs, rams with 9-12 months of age in the early puberty period, and adult rams with 3-4 years of age. Blood samples were collected to evaluate the serum 5αR2, testosterone, and dihydrotestosterone (DHT) concentrations. Subsequently, testes, epididymis, and prostate samples were collected after slaughter of the animals for histologic evaluations. Serum concentrations of 5αR2, DHT, testosterone, and the number of testicular spermatocytes, spermatids, and Leydig cells in adult rams were higher (P 0.05) than those in lambs and early puberty rams. The highest (P 0.05) population of spermatogonia cells was observed in early pubertal rams. There was a significant (P 0.05) increase in the diameter of the seminiferous tubule and its lumen, the germinal epithelium’s thickness, and the epididymis’s epithelial thickness in relation to age. The epithelial thickness and the secretory vesicle diameter of the prostate increased (P 0.05) with age. There were significant (P 0.05) positive correlations between germinal epithelium thickness and testosterone (r=0.81) as well as DHT (r=0.81) concentrations; however, it was not significant (P 0.05) for 5αR2. In conclusion, at the beginning of sexual maturity, the tissue structure of the reproductive system in rams does not reach its full development, and it is only after physical maturity that these structures reach their full development.