RESUMO
SUMMARY: This study aimed to investigate the microstructure and ultrastructure of the Bursa cloacalis (Bursa of Fabricius) (BC) in young Leiothrix lutea at various days of age (a few days after hatching) using light microscopy and transmission electron microscopy. The bird BC was sampled at 1, 5, 7, and 9 days of age. Immediately after dissection, the structure and integrity of the BC (not degenerative) were retained and the specific temporal features could be visualized precisely. After hematoxylin-eosin staining and uranyl acetate/lead citrate staining, the microstructure and ultrastructure of the BC, respectively, could be observed clearly. The microscopic observations revealed the following: in addition to change in the size of BC or lymphoid follicles, many cavities were found in the BC; the distribution of the lymphoid follicles in Leiothrix lutea was different from that in other birds; and the segregating line between the bursal cortex and medulla became increasingly clear as the age increased. In conclusion, the structural data obtained in this study provides a better understanding of the specific immunological function of the BC in Leiothrix lutea.
RESUMEN: Este estudio tuvo como objetivo investigar la microestructura y ultraestructura de la Bursa cloacalis (BC) en Leiothrix lutea joven unos días después de la eclosión, utilizando microscopía óptica y microscopía electrónica de transmisión. La BC se muestreó a los 1, 5, 7 y 9 días de edad del Leiothrix lutea. Inmediatamente después de la disección, se observó la estructura y la integridad de la CB (no degenerativa) y se pudo visualizar con precisión las características temporales específicas. Después de la tinción con hematoxilina-eosina y con acetato de uranilo /citrato de plomo, pudimos observar claramente la microestructura y ultraestructura de la BC. Las observaciones microscópicas revelaron el cambio en el tamaño de la CB o de los folículos linfoides y además, se encontraron numerosas cavidades en la CB; la distribución de los folículos linfoides en Leiothrix lutea era diferente a la de otras aves; y la línea de segregación entre la corteza bursal y la médula se hizo cada vez más clara a medida que aumentaba la edad. En conclusión, los datos estructurales obtenidos en este estudio proporcionan una mejor comprensión de la función inmunológica específica de la Bursa cloacalis en Leiothrix lutea.
Assuntos
Animais , Bolsa de Fabricius/ultraestrutura , Passeriformes/anatomia & histologia , Tecido Linfoide/ultraestrutura , Microscopia/métodosRESUMO
The allometric relation applied between the body weight and the volume increment of the interfollicular surface epithelium (ISE) showed just one developmental stage during the period analysed (from 16d old embryos through 28 old d chicks). In this single allometric developmental stage the ISE growth is relatively more pronounced than that of the bursa as a whole due to profound cellular modifications which that epithelium undergoes from the primitive undifferentiated epithelial cells through goblet and prismatic cells. The latter could have an endocytic capability due to their primary and secondary lysosomes content. A possible cellular differentiation of the ISE during the histogenesis of the cloacal bursa is also discussed.