Influence of Complexed Zinc Products on Live Performance and Carcass Grade of Broilers

Abstract Hess, J.B., Bilgili, S.F., Parson, A.M. and Downs, K.M. 2001. Influence of complexed zinc products on live performance and carcass grade of broilers. J. Appl. Anim. Res., 19: 49–60. The influence of supplementing diets with zinc (Zn) amino acid complexes on live performance and carcass quality of female (Experiment 1) and male broiler chickens (Experiment 2) was investigated. In Experiment 1, day-old female chicks were fed, under summer conditions, one of 4 dietary treatments: a control and diets supplemented with Zn (40 ppm) from Zn-methionine, Zn-lysine, or a commercial mixture of Zn-methionine and Zn-lysine. During the rearing period, body weight and feed conversion were measured. Randomly selected birds were processed with subsequent evaluation of foot pad lesions and carcass grades. In Experiment 2, male chicks were fed similar diets as Experiment 1, but under cool weather conditions. Live performance variables were measured and randomly selected- birds were processed to assess carcass defects, carcass grade, foot pad lesions and carcass yields. In Experiment 1, feed conversion and foot pad- lesions were reduced (P<0.05) in female broilers fed the Zn-amino acid, complexes, with no consistent alterations in carcass grade other than improvements in wing and back bruising. Body weight of male broilers was improved at 21d with Zn-methionine and Zn-lysine supplemented diets, with improvements in bach bruising. No differences in foot pad quality or carcass yields of male broilers was observed among the dietary treatments (P>0.05). The influence of zinc complexes on broiler live performance, carcass bruising and foot pad quality appeared to vary with environmental conditions.