Investigation of seasonal changes in serum testosterone levels and spermatogenesis in Akkaraman rams

2. ABSTRACT This study was conducted to investigate the seasonal changes in serum testosterone levels and spermatogenesis in Akkaraman rams. In this investigation, 120 Akkaraman rams, which were brought to the slaughterhouse for slaughter and whose ages ranged between 14-18 months, were used. Semen was collected by an electroejaculator. Volume, motility, concentration and rate of abnormal spermatozoa were determined in collected semen. Blood samples were taken from jugular vein and centrifuged at 5000 rpm for 10 min. After centrifugation the serum samples were allowed. The amount of testosterone was determined by coated tube RIA method using the serum stored at deepfreeze at -20°C. Tissue samples were taken from testes and cauda epididymides. Histological trimes were prepared in these tissues and examined. Diameters of seminiferous tubule were measured by the ocular micrometer. While the highest values of semen volume, sperm motility, sperm concentration and testosterone were determined as 1.11 ±0.03 ml, 84.66±1.01%, 3.21±0.07xl09/ml and 6.35±0.16 ng/ml respectively, in September, the highest values of diameters of seminiferous tubule were found as 211.80±2.19 um in October. The lowest values of these parameters were determined as 0.56±0.03 ml, 63.32±0.99%, 2.03±0.06xl09/ml, 2.69±0.08 ng/ml and 132.30±1.59 um respectively, in February. Semen volume, sperm motility, sperm concentration, amount of testosterone and diameters of seminiferous tubule reached their maximum levels in autumn and their minimums in winter. Variations of these parameters between months, seasons were statistically significant (p<0.05).There were significant (p<0.01, p<0.05) correlations among semen volume, sperm motility, sperm concentration, amount of testosterone and diameter of seminiferous tubule during four seasons. Spermatogenesis was maintained throughout the year, being the most effective in autumn, but some variations were seen in the structure of testis between autumn and the other seasons. Both mitotic and meiotic divisions increased in autumn compared to the spring, summer and winter. Spermatogonia, primary and secondary spermatocytes, round and elongated spermatids began to increase in middle August, full increases occurred during September-November and began to decline in December. Sertoli and Leydig cell concentrations were not affected by the seasonal changes. Spermatozoa concentration in the cauda epididymides was affected by the seasonal changes and it increased during autumn. In conclusion, spermatological characters and amount of testosterone in Akkaraman rams were affected significantly by changing months and seasons and these features had a positive effect on fertility and showed the most improvement especially in autumn, which is the breeding season for rams. Keywords: Ram, Spermatological Characters, Testosterone, Spermatogenesis, Season.