Histological study of the central or primary lymphoid tisues of broiler chickens

[Histology was performed in the central or primary lymphoid tisues (thymus and bursa of

Fabricius) of the twelve 25-days-old “Kasila” broilers by observation of H & E stained

sections in the Department of Anatomy and Histology, Faculty of Veterinary Science,

Bangladesh Agricultural University, Mymensingh during the period from March to October

201. Study revealed that the thymus was covered by a thin conective tisue capsule.

Numerous fine septa of conective tisue originated from the capsule and divided the organ

into many incompletely separated lobules. Each lobule was divided into a peripheral cortex

and a central medula. The population of the immunocompetent cels (lymphocytes and

immunoglobulin containing plasma cels) in the cortex were denser rather than that of medula

of the thymic lobule. The bursa of Fabricius was consisting of long thick mucosal folds

(plicae). Numerous folicles filed the lamina propria of each fold and each bursal folicle was

composed a peripheral cortex and a central medula. The population of the immunocompetent

cels in the cortex of the bursal folicle were denser rather than that of medula of the bursal

folicle. The length and width of the thymic lobules were 391.63 ± 25.874 μm and 202.50 ±

15.580 μm, bursal folicles were 594.38 ± 41.205 μm and 464.75 ± 17.721 μm respectively.

This study helps to understand the distribution of immunocompetent cels in the central

lymphoid organ of broiler.