Influence of season on stereological and histomorphometric characteristics of testes of Ouled Djellal rams in Algeria

Abstract

The aim of this study was to investigate the influence of season on testicular morphometry, on ram body weight,
testosterone concentration and on stereological structure of the testes in Ouled Djellal rams. Twenty seven rams were
randomly selected and the live weight and testicular size were recorded. At the beginning of each season (autumn,
winter, spring), among the study group, three rams were randomly selected, slaughtered and their left testes were
removed and weighed. For microscopic study, tissue samples were excised from the left testes, fixed in formalin
solution and embedded in paraffin and, afterwards, quantitative evaluation was performed. Statistical analysis
revealed that the testicular weight and morphometric parameters of the testes including length, width, thickness and
circumference were significantly (p<0.001) higher during the breeding season (autumn). The lowest seminiferous
tubule diameter (STD) (167.02±6.74µm) was observed in spring and the highest in autumn (212.12±4.94 µm) (p<0.01).
Also, tubular tissue volume and height of the germinal epithelium gradually increased during the spring, with the
highest values noticed in autumn (p<0.05 and p<0.001, respectively). Seminiferous tubule diameter significantly
correlated with scrotal circumference (r=0.54 p<0.001) and with Leydig cell number (r=0.54 p<0.001). Mean serum
testosterone concentrations were inversely related to interstitium volume (%) (r= -0.40 p<0.05) but positively
significantly related to Leydig cell number (r=0.54 p<0.001). Maximal mean serum testosterone concentrations were
observed during autumn (7.81±1.2 ng/ml), whereas minimal concentrations were noticed during spring
(3.38±0.83ng/ml) (p<0.05). It can be concluded that the morphometric parameters and stereological structure of the
testis exhibit seasonal variations in Ouled Djellal rams in Algeria.