LAUSR

Abstract Green tea powder diet supplementation effect on some immunological parameters in broiler chickens has been evaluated. To assess both the effect and the beneficial dose, the diet of 271 day-old Ross 308 male broiler chickens has been supplemented with 0, 0.25, 0.50, 0.75 and 1.00% (w/w) green tea powder in addition to feed. The experiment lasted for 21 and 42 days, respectively, for each value of the green tea supplement and for separate groups of animals. Immune response against Newcastle disease, influenza viruses and sheep red blood cells, has been determined as well as lymphoid organ (bursa of Fabricius, thymus and spleen) weights. The sero-response to avian influenza ranged between 3.7 and 6.3 lg2 (33 days) and 3.9–3.8 lg2 (42 days) for all the animals treatment groups. The total sero-response to sheep red blood cells was moderate, in a range from 1.7 to 1.5 lgT after 21 and 42 days, respectively. The plots of the weight of immune organs did not show any relation between organ weight and immunoglobulin titre. While additional data would be needed to assess the optimum supplement feed dose, it can be concluded that green tea feed supplementation is not likely to be able to induce any negative effects on immunological parameters.