The effects of Zinc-methionine and Zinc-glycine supplement on broiler performance and immunity

The effects of two sources of organic zinc on performance and immune responses of broiler chickens were evaluated by using seven-hundred and fifty day-old Arian broiler chickens which randomly allocated in 30 experimental units in a completely randomized design as a 2×3 factorial with two sources of organic zinc (zinc- methionine and zinc- glycine) and three levels of dietary zinc (40, 80 and 120 mg/kg). During the experiment, live body weight (LBW), feed intake (FI) and feed conversion ratio (FCR) were measured weekly. At the end of the experiment (age 42d) two birds from each replicate were bleed and total antibody titer against Sheep Red Blood Cell (SRBC), antibody titer against Newcastle Disease virus (ND) and differential count of white blood cells (WBC) were measured. Dietary inclusion of zinc-methionine improved LBW (day 42), FI (days 0-28) and FCR (days 0-14) in comparison with zinc- glycine (P