Histological, Histochemical and Immunohistochemical Characterization of the Testis of Double-spurred Francolin (Francolinus bicalcaratus) in a Reproductive Cycle

The double-spurred Francolin is a feral bird and remains undomesticated with very little known about its reproductive capability. This study aimed to know the structural integrity of its testis. Birds (n=5), were obtained during the dry and rainy seasons from their natural habitat in Kano, stabilized and acclimatized for two weeks in the Experimental Animal House of the Veterinary Anatomy Department, University of Ibadan. The birds were weighed, sedated and sacrificed by decapitation. The testis was removed and fixed in neutral buffered formalin and then processed histochemically for Reticulin fibres using Gordon and Sweet’s stain and Collagen fibres using Verhoff-Van Gieson stain. Paraffin-embedded sections of each fixed testis were cut and stained with Haematoxylin and Eosin, then immunostained for structural proteins with monoclonal antibodies against Vimentin, Desmin, Pancytokeratin and Alpha smooth muscle Actin. Results indicated that the mean histomorphometric values for testis and epididymis observed were highest in the early rainy season and late rainy season but lowest in the early dry season for all indexes except for the testicular capsule thickness which was lowest at the late rainy season and highest at late dry season. The testicular capsule and peritubular layer immunostained for alpha-smooth muscle actin, desmin, pancytokeratin and vimentin and were thickest during the late rainy season. The capsule was positive for collagen fibres mostly restricted to the tunica albuginea. The testicular capsule is rich in collagen and would be actively involved in keeping the testis from total collapse when it regresses in the late dry season.

Key Words: histology, histochemistry, immunohistochemistry, testis, morphometrics Francolinus bicalcaratus