Características ósseas para estimar a ingestão de manganês complexado a aminoácidos para aves de postura fase de cria

Abstract

Inorganic mineral sources have lower bioavailability and are commonly supplemented in excess in bird feed to meet requirements, while organic sources are more bioavailable and are included in smaller quantities in the diet. The present study aimed to estimate the ideal intake of manganese complexed with amino acids in the diet of laying hens during the rearing phase using bone variables. 720 Dekalb White chicks aged 1 to 6 weeks were used and distributed in a completely randomized design (DIC) in 6 treatments with 6 replications of 20 birds each. The treatments consisted of isonutritive and isoenergetic diets with levels of complexed manganese inclusion at 25, 37, 49, 61, 73 and 85 mg/kg. At the end of the experimental period, both tibias were collected from 1 bird per experimental plot. To evaluate bone variables, the following were measured and used: bone strength, densitometry (proximal, medial and distal), mineral matter and Seedor index of the tibias. The bone variables obtained were subjected to multivariate data analysis, with multivariate analysis of variance being performed, then the data were subjected to principal component analysis (PCA) and correlation matrix, and based on the results, the variables were subjected to linear and non-linear regression models to estimate the ideal intake of manganese complexed with amino acids for the breeding phase. According to the results of ANOVA and MANOVA and according to PCA, distal densitometry is the most relevant bone variable to make the estimate. The ideal intake of manganese complexed with amino acids was calculated using the models: MnCAA = Rmax.x/(km+x) and MnCAA = - r+ln((-y-Rmin-amp/y-Rmin)/s), and From the inversion of the models, an estimated consumption of 1,767 mg/bird/day of MnCAA was generated for the maximum response of medial tibial densitometry.