Substituting Zinc Bacitracin Antibiotics with Symbiotics for Post-Peak Laying Hens
Oliveira, D. PRabello, C. B. VSantos, M. J. BSilva, W. ARibeiro, A. GSilva, D. AManso, H. E. C. C. CVentura, W. R. L. MSilva Junior, R. VSiqueira, M. ASouza, L. F. ALima, T. S
The objective of this study was to evaluate the effect of adding symbiotics to the diet of laying hens in the post-peak laying period on performance variables, egg quality, and nutrient digestibility. One hundred and ninety-eight 70-week-old Dekalb White laying hens were distributed in a completely randomized design with 6 treatments, each with 6 replications of 5 and 6 birds. The treatments were: corn and soybean meal (CSM); CSM + meat and bone meal (MBM); MBM + 0.05% zinc bacitracin additive (ZnBac); MBM + 0.1% Symbiotics in three phases: layer-type chick, pullet, and laying hen (Symb-S; Symb-G and Symb-L). Data were compared by Orthogonal Contrast. The CSM treatment showed better shell thickness when compared to MBM, and a better percentage of albumen. RF and BacZn showed better yolk coloration. ZnBac showed better yolk weight when compared to Symb-S. CSM and ZnBac increased red and yellow yolk colors and Symb-G had an effect for luminosity. The gross energy apparent metabolizability coefficient (GEAMC) was better for CSM and Simb-G. The crude protein apparent metabolizability coefficient (CPAMC) was better with MBM. The dry matter apparent metabolizability coefficient (DMAMC) was better for MBM, Symb-S, and Symb-L. Thus, it is possible to replace antibiotics with symbiotics for laying hens in the post-peak phase.(AU)
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