PSVII-28 Additivity of energy concentrations and phosphorus and calcium digestibility in hatchery byproducts fed to nursery pigs

摘要

The objective of this study was to determine the additivity of energy concentrations and phosphorus (P) and calcium (Ca) digestibility in hatchery byproducts. In our previous studies, digestible energy (DE), metabolizable energy (ME), and apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) of P and Ca were determined using 10-kg barrows. Test ingredients were infertile eggs, unhatched eggs, culled chicks, and a mixture (20% infertile eggs, 20% unhatched eggs, and 60% culled chicks). It was hypothesized that determined nutritional values of the mixture is not different from predicted values calculated from nutritional values in each ingredient. A t-test was used to determine the additivity on nutritional values in the mixture. The predicted DE in the mixture was not different from the determined value (4,203 and 4,224 kcal/kg as-is; P = 0.890), and the predicted ME was not different from the determined value (3,990 and 3,998 kcal/kg as-is; P = 0.959). Predicted ATTD and STTD of P in the mixture (46.4 and 58.4%, respectively) were greater than determined values (35.5 and 47.4%, respectively; P < 0.05). However, predicted ATTD and STTD of Ca in the mixture (45.5 and 51.7%, respectively) were less than determined values (58.0 and 64.5%, respectively; P < 0.05). In conclusion, energy concentrations in a hatchery byproduct mixture could be predicted as a weighted mean of energy values in infertile eggs, unhatched eggs, and culled chicks, whereas phosphorus and calcium digestibility values in the mixture were not additive.