title: Ileal digestibility of dietary protein in the growing pig and adult human.
abstract: The suitability of the pig as an animal model for predicting protein digestibility in man was evaluated. Healthy adult human subjects (mean body weight 67 kg; n 11) and growing pigs (mean body weight 40 kg; n 15) were fed semi-synthetic mixed meals containing, as a sole source of N, casein (C), hydrolysed casein (HC) or rapeseed isolate (R). There was no prior adaptation to the test meal. Ileal digesta were sampled through a naso-ileal tube (human subjects) or a post-valve T-caecum cannula (pigs) after ingestion of a bolus meal. The protein sources were 15N-labelled. Amino acid (AA) digestibilities were not determined for R. Ileal apparent N digestibility was markedly lower (14-16 %; P < 0.001) in human subjects than in pigs (C, HC, R). Similarly, most apparent ileal AA digestibilities were lower (8 % on average; P < 0.05) in human subjects (C, HC). Ileal true N digestibility was slightly lower (3-5 %; P < 0.001) in human subjects than in pigs (C, HC, R) and most true ileal AA digestibilities were similar (P>0.05) between the species (C, HC). Exceptions were for phenylalanine, tyrosine, lysine, histidine and aspartic acid for which digestibilities were lower (3 % on average; P < 0.001) in human subjects. A similar ranking of the diets was observed for true ileal N digestibility between species. The inter-species correlation for true ileal digestibility was high for N (r 0.98 over 3 x 2 data; P = 0.11) and AA (r 0.87 over 26 x 2 data; P < 0.0001). Overall, this supports the use of the pig as a model for predicting differences among dietary protein digestibility, especially regarding true ileal N digestibility, in man.
authors.affiliation: Riddet Institute, Massey University, Palmerston North, New Zealand.
authors.forename: Amélie
authors.initials: A
authors.lastname: Deglaire
authors.forename: Cécile
authors.initials: C
authors.lastname: Bos
authors.forename: Daniel
authors.initials: D
authors.lastname: Tomé
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Moughan
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002364:Caseins / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism*; D004063:Digestion; D005260:Female; D006801:Humans; D007082:Ileum / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D023421:Models, Animal; D009584:Nitrogen / Q000378:metabolism; D009587:Nitrogen Isotopes; D013552:Swine / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D002364:Caseins; D004044:Dietary Proteins; D009587:Nitrogen Isotopes; D009584:Nitrogen