EFFECT OF SUPPLEMENTAL ZINC IN EITHER A CORN-SOYBEAN OR A MILO AND CORN-SOYBEAN MEAL DIET ON THE PERFORMANCE OF YOUNG BROILER BREEDERS AND THEIR PROGENY

Experiments were conducted to examine effects of supplemental Zn on reproductive performance of young broiler breeders (BB) and evaluate the immunocompetence of their progeny. At 20 wk of age, 36 floor pens of 5 male and 30 female BB were fed either a 1) corn soybean meal (CSB) diet; 2) CSB supplemented with ZnO; 3) CSB supplemented with Zn-Met; 4) milo and corn-soybean meal (MCSB); 5) MCSB supplemented with ZnO; 6) MCSB supplemented with Zn-Met. These diets contained 72, 112, 112, 83, 123, and 123 mg Zn/kg of diet, respectively. All progeny received the same unmedicated CSB starter diet, and therefore treatments were derived from the potential carryover of the BB diets. Supplemental Zn in either a CSB or MCSB diet resulted in no differences in egg weight, fertility, hatchability, chick weight, immune response variables, and foot pad scores of BB. The CSB diet increased (P < .05) BB antibody titers to SRBC when compared with MCSB grain sources. Supplemental Zn-Met in either a CSB or a MCSB diet fed to BB increased (P < .0001) cutaneous basal hypersensitivity to phytohemagglutinin-P in their progeny. Supplemental ZnO increased (P < .04) antibody titers to SRBC in the progeny of BB given a CSB or MCSB diet. However, progeny from BB given CSB diet had higher (P < .04) antibody titers to SRBC than progeny from BB given MCSB diet.