Assessment of low amounts of meat and bone meal in the diet of laying hens by using stable isotopes

Resumo

The aim of this study was to assess whether the inclusion of low amounts of ingredients such as wheat bran, corn gluten and yeast in the diet of laying hens can interfere with the traceability of meat and bone meal (MBM) in eggs and its fractions (albumen and yolk). We used 256 laying hens distributed across eight treatment groups, which consisted of a diet based on corn-soybean-wheat (CSW) bran meal and other diets that had additions comprising gluten and/or (MBM) and/or yeast. To analyse the isotopic ratios (13C:12C and 15N:14N), on the 28th and 56th days, 16 eggs were randomly taken for each treatment (four for each repetition), where eight eggs (two for each repetition) were used to harvest yolk and albumen samples and the remaining eight (two for each repetition) were used to analyse the whole egg. We concluded that detection of 2.0% MBM in the egg and its fractions is possible; however, the results for treatments containing gluten and yeast were not different from those containing MBM. Therefore, the inclusion of 3.0% gluten and/or yeast does not result in different ?13C and ?15N isotopic values in the egg and its fractions compared to the values obtained with the addition of 2.0% MBM in the diet.