Evaluation of supplemented zinc amino acid complexed mineral on performance of broilers fed diets with different calcium and phosphorous recommendations

    

This study investigated the performance of broilers fed diets formulated to optimize phytate hydrolysis in the upper gut and supplemented with reduced levels of Zn in the form of Zn amino acid complexed minerals (ZnAA). A total of 3,600 d-old straight-run Ross 308 broilers were randomly distributed across 72 floor pens. Birds received 1 of 6 diets (corn-soybean meal based) from day one to 37 d with 12 replicate pens per treatment, in a randomized block design. The control diet (T1) was formulated following Ca and P Aviagen 2021 Breeder recommendations supplemented with 90 ppm ZnSO4. The other 5 diets followed University of Maryland (UMD) Ca & P recommendations. The UMD diet was supplemented with 90 ppm Zn from ZnSO4 (T2) or 20 (T3), 40 (T4), 60 (T5), 80 ppm Zn (T6) as a ZnAA. All diets were supplemented with 2000 FTU phytase/kg feed. Performance data were analyzed by one-way ANOVA, using JMP 16.0. Means were separated by Tukey test when P ≤ 0.05. There was a stepwise improvement (P< 0.05) with increasing Zn for BW, FCR adjusted to mortality (cFCR) and hot carcass weight at 37d was ob[1]served at 20, 40, 60, and 80 ppm ZnAA. Breast yield (g and %) was high[1]est in birds fed 40, 60, and 80 ppm ZnAA compared to the lowest breast yield at 20ppm ZnAA. Birds fed 80 ppm ZnAA had greatest body weight at d 37 compared to birds fed T1 and T2, which were similar to each other. The FCR, however, was negatively affected in control fed birds compared to the UMD counterpart with birds fed T2 or T5 diets having 3.2 and 4.4 points improved FCR, respectively. Zinc in the form of ZnSO4 did not affect any of the carcass parameters measured. Birds fed ZnAA at 60ppm, had fewer scratched carcasses and produced a larger breast yield (g and %) compared to UMD ZnSO4 at 90 ppm and numerically to Control. Under an environment in which absorption and digestion of inorganic Zn from raw materials is maximized, the impact of supplementing diets with ZnAA as the only source of trace mineral goes beyond the performance at farm level. ZnAA at 60 ppm not only led to heavier and more efficient birds at the farm, it yielded birds with fewer scratches in their carcasses and improved breast yield.

Key Words: Zinc amino acid, broiler performance, breast yield, inorganic Zn.