Standardized ileal digestibility of amino acids differs among sources of bakery meal when fed to growing pigs

A multistate experiment involving universities in IL, IN, KY, and MN was conducted as a part of the research efforts by the North-Central Coordinating Committee-42 on swine nutrition. The null hypothesis that there are no differences in the standardized ileal digestibility (SID) of amino acids (AA) among different sources of bakery meal was tested. Eleven sources of bakery meal were procured from swine-producing states in the United States and each source was included in one diet as the sole source of AA. A N-free diet was prepared as well. Diets were prepared in one batch and divided into four sub-batches that were subsequently distributed to the four participating universities. At each university, diets were fed to 12 pigs that had a T- cannula installed in the distal ileum. Pigs were allotted to incomplete Latin square designs with 12 pigs and 4, 5, or 6 periods for a total of 21 replicate pigs per diet. Each period lasted 7 d with ileal digesta being collected from the cannulas on days 6 and 7. Samples were analyzed for AA and the SID of each AA was calculated. Results indicated that there were differences (P < 0.001) in the SID of all AA except Pro among the 11 sources of bakery meal. The differences in SID of AA observed in this experiment were greater than what is usually observed among sources of the same ingredient, indicating that there is more variability among sources of bakery meal than among different sources of other ingredients. This is likely a consequence of different raw materials being used in the production of different sources of bakery meal. Regardless of source of bakery meal, the AA with the least SID was Lys indicating that some of the raw materials in the product streams used to generate the bakery meals may have been overheated. Additionally, the Lys:crude protein ratio in each source of bakery meal was not a good predictor of the SID of Lys, which likely reflects the different raw materials being included in the different meals. In conclusion, the SID of AA varies among different sources of bakery meal and the SID of Lys is less than the SID of all other indispensable AA. Digestibility of amino acids in bakery meal varies among sources. Specifically, the digestibility of Lys is low, which requires the use of other sources of Lys in diets containing bakery meal. Lay Summary Eleven sources of bakery meal were used in a regional experiment to determine digestibility of amino acids. Diets containing each source of bakery meal were prepared at one university and distributed to three other universities. Diets were fed to pigs that had a cannula installed in the distal ileum and ileal digesta were collected from pigs for 2 d following 5 d of adaptation. Results indicated that there is considerable variation in the digestibility of all amino acids among sources of bakery meal, which is likely a reflection of differences in raw material use among different producers of bakery meal. Results also demonstrated that the digestibility of Lys is less than the digestibility of all other amino acids, indicating that some of the raw materials used in the production of bakery meal may have been heat damaged. It may, therefore, be necessary to add additional Lys to diets containing bakery meal.