The Effect of Gibberellic Acid and Vitamin E Addition to the Drinking Water of Broiler Chickens on Some Productivity, Physiological and Immunological Parameters

Abstract

Ninety chicks one day old were divided into three treatments. In which 30 chicks: control treatment was considered the first one, 150 ppm Gibberellic acid were added to the drinking water of treatment two, and 150 ppm Gibberellic acid and 30 mg per liter vitamin E for the third treatment. Weekly, chick’s weights were taken for the whole of studying period of 49 days. Liver weight, dressing percentage, and humoral immunity against Newcastle virus disease and liver enzymes ALT and AST were measured 2 times during the experiment. These 2 tests were done at 32 and 49 days old. Results of the experiment had shown no significant differences in weekly body weight and dressing percentage. Meanwhile, average liver weights of T2 and T3 were significantly higher comparing with the control on the age of 49 days at (p≤0.05). The antibody titers against NDV (both tests mean) were significantly higher (p≤0.05) in T2 compared to the average of the two periods for the third and the first sets individually.Aspartate aminotransferase (AST) effect was significantly higher in T2 and T3 comparing with the first set at 49 days aged broiler chickens, but 32 days old test showed the reverse. On the other hand, alanine aminotransferase (ALT) shows no significant differences between treatments in both times. Generally speaking, significant increases in the average levels of the three treatments of AST and ALT at the second test (49 days old chickens) as compared with average them at the first test.