Prenatal study on the development of testis and epididymis of Gaddi sheep

Abstract

newline The present study was conducted on the testis and epididymis of 68 Gaddi sheep foetii to study gross anatomy, histogenesis, organogenesis and histochemistry in different stages of gestation. The biochemical analysis was done in the foetal fluid. The samples were divided into 4 stages: stage I (31-60 days), stage II (61-90 days), stage III (91-120 days) and stage IV (121 till term) based on their age in days obtained by the formula, Y = 2.74 x X + 30.15, where X is CRL in cm and Y is age in days. The testes were located under the mesonephric kidneys which started descending into the inguinal canal at around 83rd day of gestation and started entering into the scrotum at around 95th day of gestation and finally settled into the scrotum at around 140th day of gestation. All the gross biometrical parameters increased with the increase in age of the fetus. The differentiation of cortex and medulla in the indifferent gonad was observed on 37th day of gestation. The differentiation of tunica albuginea and seminiferous tubules containing large, small and sertoli cells was observed on 46th day of gestation. The differentiation of tunica albuginea into tunica fibrosa and tunica vasculosa was evident on 50th day of gestation. The connective tissue trabeculae divided the testicular parenchyma into lobules which contained developing sex cords on 60th day of gestation. The testicular capsule and connective tissue trabeculae contained abundant reticular and collagen fibers in stage IV of gestation. The diameter of seminiferous tubules, large, small, sertoli and leydig cells increased with the progression of gestation. The epididymal duct appeared grossly as a straight elongated tubular structure adjacent to the testis on 45th day of embryonic life. The epididymal duct was distinguishable into caput, corpus and cauda regions on 70th day of gestation. The gubernaculums appeared as a cylindrical gelatinous mass and was visible in the scrotum on 86th day of gestation and appeared as a regressed knob like structure on