Histologic characterization of testicular development in Columba livia (Aves:Columbiformes)

OLEA GABRIELA, SANDOVAL MA. TERESA, HERNANDO ALEJANDRA Y LOMBARDO DANIEL

TANDIL

Jornada; Primeras Jornadas de Cs. Morfológicas de las Sierras de Tandil.; 2011

In birds, the gonads are organized and differ from one pair of genital ridges in ventrAL-medial position to the kidneys. These ridges are composed of primordial germ cells (CGPS), extra-gonadal source. At this stage are "indifferent" and it is possible to differentiate the sexes. Later in the male gonad are organized into seminiferous tubules marrow cells differentiate sex from the CGPs the steroidogenic and support, while in the female the CGPs are restricted to the cortical region. Studies of gonadal development in birds have mostly been addressed in model species such as Gallus gallus domesticus. Zaho et al. (2010), contrary to what is described above, suggest that this taxón does not exist a state of "indifferent" as the sites of colonization of CGPs differ between males and females in the early stages of development. Given these two models, the study of gonadal development in different species of birds will help to elucidate variations in the patterns of gonadal development in vertebrates. This paper describes the histogenesis in testes of Columba livia. For them, analyzed the histological testicular formation of embryos from stage (E) 21 to 44. And infants 4, 13 and 25 days post-emergence (dpe). Histological preparations were made following the techniques of staining with hematoxylin-eosin, Masson trichrome and PAS. Histological analysis shows that from the E. 21 to 24 the gonad is formed by a loose tissue of supporting cells and CGPs evenly distributed. In E. 27 begins the organization of medullary cords which form the seminiferous tubules from E. 37. At the end of embryonic development the testis seminiferous tubules presents solid, formed by spermatogonia and Sertoli cells, surrounded by Leydig cells. In infants between 13 and 25 dpe that constitution remains, however within the seminiferous tubules shows a light. These results allow us to infer an initial state of "indifferentiation" in gonadal development and provide information for comparative studies with other species of birds.