Effect of partial replacement of inorganic zinc and manganese with zinc methionine and manganese methionine on live performance and breast myopathies of broilers

Summary Feed cost represent between 60 to 70% of total poultry production cost, therefore including the correct amount of nutrients helps to improve feed efficiency and reduce production cost as less feed is required to obtain the same amount of weight gain or egg production. The level of zinc (Zn) and manganese (Mn) are typically overlooked as these minerals are usually included in the mineral premix. However, the level and form of both minerals can influence broiler performance and processing yield. This study was conducted to evaluate the effect of chelated Zn (ZinMet®) and Mn (ManMet®) on broiler performance, processing yield, and incidence of breast myopathies in broilers fed antibiotic free diets. A total of 1,280-day-old male YPM x Ross 708 broilers were randomly distributed among 4 treatments (16 replicates/treatment; 20 birds/pen). Broilers were vaccinated against coccidiosis at the hatchery, placed on litter which was top dressed with pine shavings, and raised to 46 d of age on 1 of 4 diet regimes with or without chelated Zn or chelated Mn and Zn. All diets were formulated to include 100 ppm supplemental Mn and 100 ppm supplemental Zn and formulated to be equal in methionine concentration to account for the methionine contribution of chelated Zn and Mn. Treatment 1 contained 100 ppm Zn and 100 ppm Mn from ZnSO4 and MnSO4; in treatment 2, 40 ppm Zn from ZnSO4 were replaced with chelated Zn; in treatment 3, 40 ppm Zn and 40 ppm Mn from ZnSO4 and MnSO4 were replaced with chelated Zn and Mn; and in treatment 4, 80 ppm Zn from ZnSO4 were replaced by chelated Zn on d 1 through 35 and 40 ppm Zn on d 36 through 46. Birds received a 1 × 106 cfu/ml of C. perfringens in the drinking water on d 14. Feed intake and BW were determined at 14, 35, and 46 d and feed conversion ratio (FCR) calculated by considering the weight of the mortality. On d 47, 10 birds per pen were processed to determine chilled carcass weight an on d 48, carcasses were deboned to determine meat yield and incidence of breast myopathies. Data were evaluated using ANOVA procedure and means separated by Tukey's HSD procedure with statistical significance considered at P≤0.05. Broilers fed diets with 40 ppm of chelated Zn and Mn sources had a trend towards higher BW (P=0.056) in comparison to birds fed diets containing only inorganic Zn and Mn sources. Replacement of 40 ppm of inorganic Zn and Mn with chelated Zn and Mn improved FCR (P≤0.05) and increased carcass weight (P≤0.05). Birds fed inorganic Zn and Mn had lower breast meat weight (P≤0.05) compared to the other treatments. The incidence of breast myopathies was not influenced by the source of Zn and Mn. The inclusion of chelated Zn and Mn improved FCR, carcass weight, and breast meat weight of broilers from 1 to 46 d.