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چکیده
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Introduction: Bursa of Fabricius plays an essential role in the avian immune system. The maturation and differentiation of the B cells, responsible for the humoral immunity, occurs in this organ. Its shape can be variant, from round to cylindrical. The inner blades contain lymphoid follicle packs within a net of conjunctive tissue, covered by a cylindrical or columnar epithelium. In young chickens the bursa grows fast, achieving its top size between 4th and the 12th weeks. It often reduces rapidly after the 20th week. Objective: This work aims at characterizing the Bursa of Fabricius from the histological point of view. Materials and Methods: For the sake of this research, clinic exam and necropsy was performed to 20 White Leghorn chicken of 6 week. The Bursa of Fabricius were taken, fixed in 10% formol, and the histological sections were stained with hematoxilin- eosin. Results and conclusion: It was seen that the surface epithelium covering the inner bursa surface is separated from the follicles by a fine connective tissue which is interrupted in some segments and it is possible to observe a continuousness between this epithelium and the called reticular that divides the marrow cortex. There is no reference of this finding on the revised bibliography on the bursa histology. However, our study demonstrates this element that is even more evident in the infection by the Gumboro disease virus. Another relevant aspect is what is said about apoptosis (natural process in which a cell disintegrates after reaching a certain age or due to poor cell health) normally occurring in the medullar follicles zone.
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