Prediction of the standardized ileal true digestibility of amino acids from the chemical composition of oilseed meals in the growing pig

Digestibility experiments using growing pigs fitted with an ileorectal anas tomosis were performed to measure the standardized ileal true digestibility (ITD) of amino acids in five cotton seed meals (CSM) and three palm kernel meals (PKM), differing in their level of non starch polysaccharides (NSP), as expressed by NDF content and the nitrogen content of NDF (N NDF). The N DF content in CSM ranged from 273 to 475 g kg(-1) on dry matter (DM) and th e crude protein content from 384 to 506 g kg(-1) DM. The latter values were not correlated with the NDF content. For PKM, NDF varied from 592 to 686 g kg(-1) and the crude protein content from 151 to 177 g kg(-1). Results obt ained for CSM clearly demonstrate a curvilinear relationship, except for me thionine, between ITD of amino acids and NDF content. Furthermore, if the c omposition of the CSM as ash, fat, total nitrogen, nitrogen from NDF (N NDF ) and total gossypol (TGOS) contents is known (g kg(-1) DM), the quantity o f digestible amino acid can be predicted for lysine, threonine and tryptoph an with reasonable precision, but less for sulfur amino acids. As an exampl e for lysine, dLys (g kg(-1) DM) = 6.5116(1.0939) + 0.1411N(0.0158) - 0.167 3NNDF(0.0091) - 0.0124NDF (0.0010) R-2 = 0.993, For PKM, the relationships were more difficult to assess because of a narrow range in NDF level and th e heterogeneity of response between pigs, especially for the higher NDF con tents. In addition, the current data confirmed that the nitrogen content in the NDF fraction of NSP, often considered in ruminant protein nutrition, c ould be also an useful predictor of true ileal digestible values for select ed amino acids in the pig, (C) 2001 Elsevier Science B.V. All rights reserv ed.