Effects of Feeding Methionine Hydroxyl Analogue Chelated Zinc, Copper, and Manganese on Growth Performance, Nutrient Digestibility, Mineral Excretion, and Welfare Conditions of Broiler Chickens: Part 2: Sustainability and Welfare Aspects

This study investigated the effects of the dietary supplementation of mineral methionine hydroxyl analogue chelates (MMHACs) zinc (Zn), copper (Cu), and manganese (Mn) on excreta nitrogen and mineral levels, housing conditions, and the welfare status of broilers. Three-hundred eighty-four day-old Ross 308 male chicks were randomly distributed to four dietary treatments, each consisting of eight replicate pens of twelve birds per pen. The treatments were (1) inorganic trace mineral ZnSO₄ (110 ppm), CuSO₄ (16 ppm), and MnO (120 ppm) (ITM); (2) MMHAC Zn (40 ppm), Cu (10 ppm), and Mn (40 ppm) (M10); (3) inorganic trace mineral ZnSO₄ (110 ppm), tribasic copper chloride (125 ppm), and MnO (120 ppm) (T125); and (4) MMHAC Zn (40 ppm), Cu (30 ppm), and Mn (40 ppm) (M30). Three feeding phases including the starter (days 0–10), grower (days 10–21), and finisher (days 21–42) were used. The findings showed that birds offered MMHACs at both levels had significantly lower Zn and Mn levels, and birds offered the T125 diet had higher Cu levels in the excreta compared to those fed the other diets on days 10, 16, 21, 28, and 42 (p < 0.001). The life cycle assessment showed that MMHAC supplementation at 30 ppm can be expected to improve the sustainability of the poultry industry in terms of reduced emissions into the environment, whereas excreta nitrogen and moisture content, litter conditions, levels of air gases (ammonia, carbon dioxide, and methane), and welfare indicators were similar between the dietary treatments. Hence, the supplementation of MMHACs to broiler diets at 30 ppm could maintain litter quality and welfare status while reducing emissions into the environment and the Zn, Mn, and/or Cu excretion of broilers, therefore reducing the environmental impacts of broiler production.