The aim of the study was to compare the production results, slaughter value, and physicochemical and biochemical parameters of the muscles of Ross 308 broiler chickens. The study included 225 individuals divided into three groups of 75 birds each. Each group was subdivided into three subgroups of 25 birds each (replicates). The control group received zinc (Zn) in the form of zinc oxide (ZnO) and copper (Cu) in the form of copper (II) sulfate pentahydrate (CuSO4·5H2O). Experimental group I received the microelements zinc and copper exclusively in the form of zinc hydroxychloride and dicopper chloride trihydroxide. Experimental group II received zinc and copper in both inorganic and hydroxychloride forms. The obtained results were processed using statistical analysis using the STATISTICA 13.0 2016 program. The significance of differences between groups was inferred based on Tukey’s test. Chickens from the experimental groups were characterized by higher body weight (p ≤ 0.05) and eviscerated carcass weight (p ≤ 0.05) and better feed utilization (p ≤ 0.05). Moreover, compared with the control group, the carcasses of chickens from the experimental groups were characterized by a lower weight of breast muscles (p ≤ 0.05) and skin with subcutaneous fat, a similar weight of leg muscles, and a significantly greater weight of the remaining carcass components (p ≤ 0.01). The use of Zn and Cu in the form of hydroxychlorides in broiler chicken nutrition increased the fat content in the muscles (p ≤ 0.05), the concentrations of Zn and Cu in the liver, and significantly improved the tibial bone strength of broiler chickens. The application of Zn and Cu in the form of hydroxychlorides in the diets (experimental groups I and II) enhanced lipid and protein oxidation processes and the overall antioxidant capacity in the breast muscle. To conclude, dietary supplementation with zinc and copper hydroxychlorides in broilers promotes growth performance, bone strength, and mineral bioavailability, though it reduces breast muscle yield and triggers oxidative stress in these tissues.
Kaim-Mirowski et al. (Fri,) studied this question.