RESUMO
The objective of the study was to evaluate the deposition of selenium in the breast muscle of broilers fed different selenium sources during different periods. Two experiments were carried out with broilers fed 45% sodium selenite (SS) or 2% hydroxy-selenomethionine (HSM) to determine the selenium deposition rate in the muscle tissue. In Experiment 1, 48 broilers were distributed in a completely randomized design with six treatments with eight replicates each, consisting of diets containing 0 Se (0), 200 or 400 µgSS/kg (200 SS, 400 SS), or 100, 200, or 300 µgHSM/kg (100 HSM, 200 HSM, 300 HSM) for 10 days. The highest Se breast content was obtained with 300 HSM diet, followed by 200 SS diet compared to the other treatments. Experiment 2 had a completely randomized design following a plot scheme subdivided in time, and consisted of a basal diet supplemented with 300 µg SS/kg (300 SS), basal diet with 200 µg HSM/kg (200 HSM) or basal diet supplemented with 100 µgSS/kg and 100 µgHSM/kg (100 SS+100 HSM). Dietary Se sources did not influence Se breast content measured on days 3 and 6. However, on days 9 and 12, higher Se breast contents were measured in broilers fed 200 HSM and 100 SS+100 HSM diets compared with those fed 300 SS diet. In conclusion, the supplementation of broiler diets with HSM at 2% for a short period is more efficient to increase selenium deposition in the breast muscle than sodium selenite.
Assuntos
Animais , Carne/análise , Galinhas/fisiologia , Galinhas/metabolismo , Ração Animal/análise , Selênio/análiseRESUMO
The objective of the study was to evaluate the deposition of selenium in the breast muscle of broilers fed different selenium sources during different periods. Two experiments were carried out with broilers fed 45% sodium selenite (SS) or 2% hydroxy-selenomethionine (HSM) to determine the selenium deposition rate in the muscle tissue. In Experiment 1, 48 broilers were distributed in a completely randomized design with six treatments with eight replicates each, consisting of diets containing 0 Se (0), 200 or 400 µgSS/kg (200 SS, 400 SS), or 100, 200, or 300 µgHSM/kg (100 HSM, 200 HSM, 300 HSM) for 10 days. The highest Se breast content was obtained with 300 HSM diet, followed by 200 SS diet compared to the other treatments. Experiment 2 had a completely randomized design following a plot scheme subdivided in time, and consisted of a basal diet supplemented with 300 µg SS/kg (300 SS), basal diet with 200 µg HSM/kg (200 HSM) or basal diet supplemented with 100 µgSS/kg and 100 µgHSM/kg (100 SS+100 HSM). Dietary Se sources did not influence Se breast content measured on days 3 and 6. However, on days 9 and 12, higher Se breast contents were measured in broilers fed 200 HSM and 100 SS+100 HSM diets compared with those fed 300 SS diet. In conclusion, the supplementation of broiler diets with HSM at 2% for a short period is more efficient to increase selenium deposition in the breast muscle than sodium selenite.(AU)
Assuntos
Animais , Carne/análise , Galinhas/metabolismo , Galinhas/fisiologia , Selênio/análise , Ração Animal/análiseRESUMO
An experiment was carried out to evaluate the digestibility and metabolizability of corn and a corn/soy-based diet with the inclusion or not of xylanase and/or phytase in broilers. In the trial, 1,120 broiler chicks were distributed according to a completely randomized experimental design, consisting of 16 treatments, with 10 replicates of 7 birds each. Treatments were evaluated following a factorial arrangement (4 × 2 × 2), with 4 xylanase levels (zero, 50, 100, or 150 fungal ß-xylanase units/kg; FXU), 2 phytase levels (zero or 1,000 phytase units/kg; FTU), and 2 diets (corn/soy or pure corn). The same basal diets were fed from one to 14 d post hatch for all birds, after which the experimental diets were provided until d 25. All birds were euthanized on d 25 for collection of ileal contents. Samples of feed, excreta, and ileal digesta were analyzed for determination of apparent ileal digestibility. The effect of xylanase on the coefficient of apparent dry matter metabolizability and apparent metabolizable energy was increased by the presence of phytase in the complete diet but not in the diet based on pure corn resulting in a diet*phytase*xylanase interaction (P < 0.01; P < 0.001, respectivaly). Equivalent effects were observed for the apparent coefficient of ileal protein digestibility in which xylanase effects were potentiated by the presence of phytase only in the complete diet, resulting in a significant 3-way interaction. In corn there was a limitation in improving digestibility when we added increasing levels of xylanase with phytase. Otherwise in the corn/soy-based diets, the enzymes were potencialized when they were added together. The fact that the effect of xylanase was enhanced by the presence of phytase in complete diets but not in pure corn may be associated with differences in substrate (arabinoxylan and/or phytate) concentration and presentation, diet nutrient balance, or other factors. It can be concluded that the interactive effects of xylanase and phytase can be substantial but may depend on the characteristics of the diet fed.