ARS | Publication request: Comparison of amino acid digestibility coefficients for soybean meal, canola meal, fish meal, and meat and bone meal among 3 different bioassays

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 15, 2012
Publication Date: May 15, 2012
Citation: Kim, E.J., Utterback, P.L., Parsons, C.M. 2012. Comparison of amino acid digestibility coefficients for soybean meal, canola meal, fish meal, and meat and bone meal among 3 different bioassays. Poultry Science. 91:1350-1355.

Interpretive Summary: Formulating broiler diets on a digestible amino acid (AA) basis is advantageous to broiler producers when compared to formulating on a crude protein basis. Currently, three bioassays are available for determining AA digestibility of feedstuffs; the precision-fed cecectomized rooster assay; the standardized ileal chick assay, and a precision-fed broiler chick assay. The objectives of this study were to compare AA digestibility of several commonly used protein sources; soybean meal, canola meal, fish meal, and meat and bone amongst the three methods. Results of the study indicate that there were no consistent differences in AA digestibility amongst the methods and values were in general agreement, particularly for soybean meal and meat and bone meal which have higher protein contents (49 and 54%, respectively). Differences amongst the methods were observed for fish meal but these differences were not consistent among the different methods or amino acids. Based on the results of this study, all three methods are acceptable methods for determining AA digestibility in soybean meal, canola meal, meat and bone meal, and fish meal in poultry.

Technical Abstract: The objective of this study was to determine amino acid digestibility of 4 feedstuffs [soybean meal (SBM), canola meal, fish meal, and meat and bone meal (MBM)] using the precision-fed cecectomized rooster assay (PFR), the standardized ileal assay (SIAAD), and a newly developed precision-fed ileal broiler assay (PFC). For the PFR, cecectomized roosters were precision-fed approximately 30 g of feed sample, and excreta were collected 48 h postfeeding. For the SIAAD, 16-d-old broilers were fed a semipurified diet containing the feed samples as the only source of protein from 17 to 21 d, with ileal digesta collected at 21 d. For the PFC, 22-d-old broilers were precision-fed10 g of feed sample mixed with chromic oxide, and ileal digesta were collected at 4 h postfeeding. Digestibility coefficients were standardized using a nitrogen-free diet for the SIAAD and PFC and using fasted roosters for the PFR. There were generally no consistent differences in standardized amino acid digestibility values among assays, and values were in general agreement among assays, particularly for SBM and MBM. Differences did occur among methods for amino acid digestibility in fish meal; however, these differences were not consistent among methods or amino acids. The results of the study indicated that all 3 bioassays are acceptable for determining the amino acid digestibility of SBM, canola meal, MBM, and fish meal for poultry.