Determinação de metais por técnicas espectroanalíticas em amostras de carne e sangue de bovinos submetidos à dieta com adição de erva-mate (Ilex paraguariensis, St. Hilaire)

Abstract

Given the importance of quality in the bovine meat and its relationship with the diet submitted to animals, this master dissertation has the proposition to evaluate the Ca, Cu, Fe, K, Mg, and Zn concentrations changes in blood and meat of bovines that ingested feed supplemented with yerba mate. The experiment was conducted with 48 male of bovines, which were confined and shared into 4 groups. The first one was feed without the addition of yerba mate and the others had 0.5; 1.0; and 1.5% of yerba mate added to the total mass of their diets. After slaughter, samples of feed and yerba mate, and blood, liver, and muscle of slaughtered animals were freeze-dried, ground and then microwave assisted digested in HNO3 and H2O2 medium. The analytes Ca, Mg, K, Fe, Cu, and Zn were quantified in the feed, yerba mate, and blood by inductively coupled plasma optical emission spectrometry (ICP OES). The same analytes were quantified in the muscle and in the liver by microwave inductively plasma optical emission spectrometry (MIP OES). The methods were validated with the use of certified reference materials and statistically similar results to the certified values were obtained, with appropriates limits of detection and quantification. Principal component analyses (PCA) were performed to evaluate the influence of the addition of yerba mate combined with the variables weight, age, fat layer, and animal genetic in the liver results. The amount of added yerba mate was the leading cause of differences among the analytes results, which were not affected by the other variables. Samples of blood, liver, and muscle presented differences between the analytes concentrations with the different treatments. However, the results showed variations among the different treatments and sample sorts. In muscle matrix, higher levels of evaluated analytes in animals feed diets were obtained with 1.0% mate addition. On the other hand the highest concentration varied between treatments with 0.5 and 1.5% of mate in the samples of blood. By PCA performed with the liver samples, it was observed that except for Fe, the amount of added mate extract caused significant effect compared to control group (0%) and the group receiving the highest dosage of mate (1.5%), especially for K, Mg, and Ca.