Hamedi, S., T. Shomali, R. Akbarian, A. S. Zandi & S. Sadeghi, 2017.

Effect of levamisole on active antibody titres and histomorphometric parameters of immune organs in broiler chickens.

Bulg. J. Vet. Med., 20, No 2, 174–182.

Use of immunomodulators has increased, particularly in poultry production around the world. The study evaluates effect of levamisole HCl (LMS) as an immunostimulatory agent on antibody titres and histomorphometric parameters of caecal tonsils, bursa and thymus of broilers. Sixty chickens were treated with 0 (control), 2, 5, 10, 15 and 25 mg/kg LMS in drinking water for 45 days. Antibody titre against ND, AI, IBD and IB was assayed periodically. At the end of the experiment, histological sections were made from caecal tonsils, bursa and thymus. LMS had no effect on body, caecal tonsil and bursa weights. Treated birds, except those at 15 mg/kg, showed significantly higher antibody titres in some of the sampling occasions. In caecal tonsils, the highest dose had the most remarkable effect. In bursa, the most profound effect of this dose was on number of follicles per plica. Thymus was the least affected organ. In conclusion, LMS administration affected positively active antibody titres and histomorphometric parameters of caecal tonsils, bursa and less profoundly thymus in normal broilers.

Key words: antibody, bursa of Fabricius, caecal tonsil, histomorphometry, levamisole, thymus