Ileal digestibility of amino acids and estimates of endogenous amino acid losses in pigs fed wheat, triticale, rye, barley, maize and sorghum

Forty-three batches of cereals (10 of wheat, 10 of triticale, 5 of barley, 5 of rye, 7 of maize and 6 of sorghum) were analysed and studied for their nitrogen (N) and amino acid (AA) ileal digestibility. Each batch was tested on four castrated male pigs, weighing between 30 and 90 kg, and fitted wit h an end-to-end ileo-rectal anastomosis. Ileal true digestibility (TD) of A A was calculated by correcting ileal apparent digestibility (AD) for basal endogenous AA losses, measured by means of a protein-free diet. Ileal real digestibility (RD) of AA was calculated by correcting AD for total endogeno us AA losses, estimated by a multiple regression model. TD of N and most AA decreased (P < 0.001) from wheat, triticale and maize, to barley and sorgh um and to rye (90.3, 88.7, 89.9, 85.4, 83.7 and 80.1%, respectively, for th e sum of all AA). Estimates of endogenous N losses decreased (P < 0.001) fr om triticale, sorghum and wheat, to maize, barley and rye (on average 3.10, 2.93, 2.63, 2.43, 2.27 and 2.16 g N.kg(-1) DM ingested, respectively). Bar ley excluded, there was a trend toward increasing endogenous AA losses with increasing dietary acid detergent fibre (ADF) concentration (r = 0.57, P < 0.001). Barley caused low endogenous N losses relative to its ADF concentr ation.