Effect of a 2-month light cycle regimen on testicular parameters of adult Ile-de-France rams

This experiment was conducted in Ile‐de‐France adult rams to examine the target point of a 2‐month light cycle regimen on seminiferous tubule functions, on intertubular compartment and on Leydig cell parameters. Eight rams were subjected to a 2‐month light cycle regimen and were compared to sexually active or inactive rams. In light‐treated rams, testis weight was maintained equal or was higher than that of sexually active rams. Both tubular and intertubular tissues were found significantly higher in light‐treated than in sexually active rams. The mean ratio of basement membrane area of the seminiferous tubules per Sertoli cells and the daily productions of A1 spermatogonia and of leptotene primary spermatocytes were significantly increased in light‐treated rams as compared with sexually active or inactive rams. Meanwhile, the dairy productions of diplotene primary spermatocytes, of round spermatids, of spermatozoa and of the rete testis fluid were not significantly increased in light‐treated as compared with sexually active rams but significantly greater than those of sexually inactive rams. Total volume, total numbers, and individual volumes of Leydig cells were at least equal or higher in light‐treated than in sexually active rams.