Variação sazonal na morfologia dos ductos eferentes distais em codorna doméstica mantida em cativeiro experimental

Abstract

Neste estudo diferenças expressivas foram observadas na estrutura dos ductos eferentes distais (DED) de codorna doméstica Coturnix coturnix, da variedade italiana, mantida em cativeiro experimental durante dois anos, durante as quatro estações do ano. A variabilidade morfológica dos DED foi mais marcante na primavera e no outono, eqüivalendo às fases ativa e quiescente do ciclo reprodutivo anual (ciclo testicular) nesta ave. Nessas fases do ciclo, diferenças significativas foram observadas na ultraestrutura das células principais (P) e ciliadas (C) do epitélio de revestimento tubular e nos calibres tubulares. Estes tiveram valores médios maiores na primavera, com valores similares no verão e no inverno, e valores médios menores observados no outono. Na primavera, no citoplasma apical de células P, notou-se maior complexidade organelar, inferindo-se a ocorrência de processos endocitóticos ativos. A quiescência outonal caracterizou-se por redução do calibre tubular dos DED, luz tubular vazia de espermatozóides, degenerações de organelas citoplasmáticas e debridamentos citoplasmáticos apicais em células P e C. No inverno e verão, correspondentes às fases recrudescente e regressiva, respectivamente, do ciclo testicular nesta espécie, os dados obtidos foram, de modo geral, similares aos observados na primavera.

Some expressive differences were noted on the distal efferent ducts (DED) morphology in domestic quail of the Italian variety along the year. The birds were maintained on experimental captive breeding along two consecutive years, before the morphologic studies. Morphologic differences on the DED had been more evident in spring and autumn respectively, the active and quiescent phases of the annual testis cycle. Variability more expressive was noted among the principal (P) and ciliated (C) epithelial cells and in tubular diameters of DED, during the two focused seasons. Spring features of DED were marked by relative enlargement of the passageways, with similar results in summer and winter, and characteristic organelle development on the apical cytoplasm of P cells, allowing to conclude presence of active process of endocytosis. Autumn quiescence was marked by an enfolding pattern of all the tubular passageways, lacking of spermatozoa and small amount of heterogeneous material inside their luminal compartments, followed by presence of ultrastructural degenerative features in apical cytoplasm of P cells and C cells in DED passageways. Tubular features verified in DED during winter and summer were minor and similar to those described in spring. Summer and winter were respectively considered the recrudescent and regressive phases of the testis cycle in these species, based on the spermatogenesis cycle analysed in all the seasons of the year as well as on the base the morphologic features here found.