Digestibility of amino acids in maize,wheat and barley meal,measured in pigs with ileo-rectal anastomosis and isolation of the large intestine

Maize, soft wheat and barley diets were compiled to have similar crude fibre (CF) concentration by addition of purified cellulose. Protein-free diets, with purified cellulose included at 60 g kg^?1 dry matter (DM) (PF1) and 90 g kg^?1 DM (PF2), were formulated. Each of four littermate, male pigs (22 kg liveweight) was surgically modified to create an ileo-rectal anastomosis with complete isolation of the large intestine. Diets were fed, and the ileal digesta, excreted via the anus, were collected. Endogenous amino acid output was higher after feeding PF2 than PF1. The choice of factor for correction of apparent digestibility (AD) to true digestibility (TD) was based upon CF intake of cereal diet. AD of most essential amino acids was greater in wheat than in maize or barley, although AD of lysine in barley (67.1%) was higher than in maize (56.8%) or wheat (63.4%). TD of most essential amino acids was higher for wheat and maize than for barley, although TD of lysine was similar for all cereals. Lysine and threonine were the most poorly digested essential amino acids in all cereals.