Minerais complexados com aminoácidos em dietas de poedeiras da fase de cria ao período final de produção

Abstract

Representing 3 to 4% of the live weight of birds, minerals are the organic constituents that act by performing various functions in the animal organism. In commercial practices, poultry diets are supplemented with inorganic salts, which have low bioavailability and high excretion rates. Thus, the use of mineral sources linked to organic molecules appears as an alternative to increase the efficiency of use and reduce the impacts of age on production performance, eggshell quality and environmental pollution. In the period from one day of life to 30 weeks of age, two groups of birds were fed with two mineral sources: inorganic (70, 70 and mg/kg of Zn, Mn and Cu) or reduced inorganic (40, 40, 2 .75 mg/kg Zn, Mn and Cu) associated with minerals complexed to amino acids (30, 30, and 5.25 mg/kg). And during the period from 30 to 93 weeks of age, 640 laying hens, 320 from each initial group, were redistributed into four groups, defining a 2 x 4 factorial arrangement with eight replicates of 10 birds. The treatments consisted of: MI– containing 70, 70, 8 mg/kg of Zn, Mn, Cu from inorganic mineral sources; 2) MCA-AMC – partial replacement of inorganic mineral sources by 30, 30 and 5.25 mg of Zn, Mn and Cu complexed to amino acids; 3) MCA-ZMCFe – partial replacement of inorganic sources by 30, 30, 5, 25 and 40 mg/kg of Zn, Mn, Cu and Fe; 4) MCA-Fe - partial replacement of the inorganic iron source by 40 mg/kg Fe complexed to amino acid. The effects of mineral sources on the variables of productive performance, bone characteristics, egg quality, tissue mineral composition (bone and liver), egg yolk and excreta, as well as blood variables (alkaline phosphatase, corticosterone and triiodothyronine) were evaluated and the effects of sources on the microstructure of eggshells and distribution of mineral elements on the shell. The data obtained were subjected to analysis of variance and means were compared by Tukey's test (P<0.05). There was an interaction effect for the variables of quality of eggs, bone, blood and for the palisade, nipple layers, and width of the nipple buds of the eggshells of birds supplemented with MCA. The use of MCA-ZMC from CF in partial replacement of inorganic sources, and the maintenance of this supplementation in association with MCA-Fe delayed the impacts of age on bone characteristics and eggshell quality during PF, influencing positively the activity of phosphatase, maintenance of bone integrity and thickness of the shell and its microstructures, promoting better quality shells at the end of the production period, without affecting the productive performance of the birds. Partial supplementation of birds with MCA-ZMC from birth to 93 weeks of age did not determine higher mineral concentrations in bone tissue, liver, egg yolk and bird excreta. Only supplementation of birds during the final production phase, independent of supplementation during the growth phase, provided higher concentrations of Fe and Cu in the liver, in addition to Mn in the yolk and excreta of the birds.