Performance and Some Immunological Parameter Responses of Broiler Chickens to Licorice (Glycyrrhiza glabra) Extract Administration in the Drinking Water

This study was conducted to evaluate the effect of Glycyrrhiza glabra root (licorice) extract (LE) administration through drinking water on the performance and some immunological parameters of broiler chickens. A total of 320 onedayold broiler chicks (Cobb 500) according to a completely randomized design were assigned into four treatment groups, namely 0LE, 0.1LE, 0.2LE and 0.3LE because the experimental treatments comprised a control (no inputs) and/or three levels of LE (0.1, 0.2 and 0.3 mg/L drinking water). There was not a significant difference in body weight; feed intake and feed conversion ratio among the birds given the control or the LE levels during the experiment (P > .05). Similarly, LE supplementation through drinking water had no significant (P > .05) effect on immunological parameters including antibody titers against Newcastle disease and Influenza viruses, heterophil and lymphocyte percentages and heterophil to lymphocyte (H/L) ratio as well as liver and lymphoid organ (bursa of Fabricius, thymus and spleen) weights.