A total number of eighteen day old Hansli chicks and eighteen day old Vencobb broiler chicks were divided into three age groups viz. group I (up to 1 month), group II (1-3 months) and group III (3-6 months) with six birds in each age group. On each observation day (4th week, 12th week and 24th week), six birds from each breed were used for the study of histochemical features of the thymus, spleen and bursa of Fabricius. It was found that the capsule, septa and tunics of blood vessels revealed age specific PAS activities, whereas the Alcian blue activities varied with age and was restricted to the thymic capsule and trabeculae. The splenic capsule, tunics of blood vessels and intercellular region of splenic white pulp revealed age specific PAS positive activity, whereas the Alcian blue activity was only reported in the splenic capsule of 12th week age Hansli chicken and Vencobb broiler chicken. The apical borders of both follicle associated epithelium and interfollicular epithelium, sub-epithelial region, cortico-medullary junction, medulla of lymphoid follicle, interfollicular connective tissue, central connective tissue core of bursal plicae, walls of blood vessels, tunica muscularis and tunica serosa revealed age specific PAS activities, whereas the apical borders of follicle associated epithelium (FAE), interfollicular epithelium (IFE) and goblet cells of lining surface epithelium, tunica muscularis and tunica serosa showed age specific Alcian blue activities in both the birds.
Key words: Bursa of Fabricius, Hansli, histochemical, spleen, thymus, Vencobb