Effects of dietary β-mannanase supplementation on the additivity of true metabolizable energy values for broiler diets

다국어 초록 (Multilingual Abstract)

Objective: This experiment was conducted to determine the effects of dietary ${\beta}$-mannanase on the additivity of true metabolizable energy (TME) and nitrogen-corrected true metabolizable energy ($TME_n$) for broiler diets. Methods: A total of 144 21-day-old broilers were randomly allotted to 12 dietary treatments with 6 replicates. Five treatments consisted of 5 ingredients of corn, wheat, soybean meal, corn distillers dried grains with solubles, or corn gluten meal. One mixed diet containing 200 g/kg of those 5 ingredients also was prepared. Additional 6 treatments were prepared by mixing 0.5 g/kg dietary ${\beta}$-mannanase with those 5 ingredients and the mixed diet. Based on a precision-fed chicken assay, TME and $TME_n$ values for 5 ingredients and the mixed diet as affected by dietary ${\beta}$-mannanase were determined. Results: Results indicated that when ${\beta}$-mannanase was not added to the diet, measured TME and $TME_n$ values for the diet did not differ from the predicted values for the diet, which validated the additivity. However, for the diet containing ${\beta}$-mannanase, measured $TME_n$ value was greater (p<0.05) than predicted $TME_n$ value, indicating that the additivity was not validated. Conclusion: In conclusion, the additivity of energy values for the mixed diet may not be guaranteed if the diet contains ${\beta}$-mannanase.