Histomorphology and histochemistry of testis of indigenous bull (<i>Bos indicus</i>) of Bangladesh

Abstract

Histomorphological and histochemical features of testes were studied in six adult indigenous bulls (Bos indicus) of two different age groups, 1 year 9 months to 2 years of age (group A) and 2 years 3 months to 2 years 6 months of age (group B) during the period from September 2006 to April 2007 by using Hematoxylin and Eosin (H&E) stain, Verhoeff's stain, Van Gieson's stain and Periodic Acid-Schiff Reaction (PAS) stain. The testes were surrounded by visceral layer of tunica vaginalis (consisted of mesothelium and connective tissue) and tunica albugenia mainly composed of collagen fibers. The seminiferous tubules were tortuous, two ended loops and varying in appearance and the wall of tubules consisted of lamina propria, basement membrane supported by reticular fibers and a lining of complex stratified epithelium consisted of sertoli cells and spermatogenic cells. The sertoli cells are irregulary columnar cells, extended from basal lamina to lumen of tubules and the spermatogenic cells situated between the sertoli cells in an orderly manner with four to eight layers occupying the space between the basal lamina and the lumen of the tubules. There was presence of both spermatid and spermatozoa in the lumen of some seminiferous tubules of testes of bulls of both age groups. The spermatogonia, primary spermatocytes and secondary spermatocytes showed more staining affinity than the spermatid in routine staining technique. The basement membrane of tubules, spermatid and spermatozoa showed positive affinity whereas spermatogonia, primary spermatocytes and secondary spermatocytes showed negative affinity to PAS stain. The interstitial tissues located between the sminiferous tubules, consisted of connective tissue network, mainly composed of collagenous and reticular fibers; blood and lymph vessels with Leydig cells. The Leydig cells were present as single or groups within intertubular spaces. It was concluded that the thickness of tunica albuginea, the stratification of growing spermatogenic cells and cross sectional length and breadth of the seminiferous tubules of testes were higher in the bull of group B than group A and the number of Leydig cells were more in the testis of group A than group B and in between left and right testes, the thickness of tunica albuginea and cross sectional length and breadth of the seminiferous tubules were higher in the left testis but the number of Leydig cells was higher in right testis in both age groups.

Key words: Testis, seminiferous tubule, Leydig cell, indigenous bull

DOI = 10.3329/bjvm.v6i1.1341

Bangl. J. Vet. Med. (2008). 6 (1): 67-74