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-I dry matter (OM) (PFl) and 90 g kg-I DM (PIC?), were formulated. Each of four littermate, male pigs (22 kg liveweight) was surgically modified to create an ileo-rectal anastomosis with complete kolation 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 PFZ than PFl. The choice of factor for correction of apparent digestibility (AD) to true digestibility (TO) was based upon CF intake of cereal diet. A D of most essential amino acids was greater in wheat than in maize or barley, although A D of lysine in barley (67.1%) was higher than in maize (56.8%) or wheat (63.4%). T D of most essential amino acids was higher for wheat and maize than for barley, although T D of lysine was similar for all cereals. Lysine and threonine were the most poorly digested essential amino acids in all cereals.

1. Maize, wheat and barley meals, and a protein-free diet were each force-fed to 24 intact and 24 caecectomised adult cockerels. For each test, birds were starved of solid food for 48 h, fed, and then excreta collected for 48 h. 2. Quantities of nitrogen (N) and amino acids excreted after feeding the protein-free diet did not differ between intact and caecectomised birds. 3. True digestibility coefficients of N and amino acids did not differ between intact and caecectomised birds. 4. Differences between cereals in apparent digestibility of amino acids were inconsistent and more readily attributed to differences between amino acid intake than bioavailability. 5. Differences between cereals in true digestibility of amino acids were confined to higher values for N, aspartic acid, alanine and leucine in maize than in barley or wheat meals.

1. Three isonitrogenous diets were formulated in which soyabean (dehulled), sunflower (hulled) and groundnut (dehulled) meals were the sole protein sources. 2. 50 g of each diet was tube-fed to each of 24 intact and 24 caecectomised cockerels, which had been previously starved for 48 h. Excreta were collected, individually, for 48 h. The concentrations of amino acids in the diets and excreta were determined, and digestibility coefficients calculated. 3. Differences between intact and caecectomised birds for true digestibility evaluations reached significance for threonine, glycine and lysine only. Deamination of threonine and glycine, and synthesis of lysine, in the caeca was implied. 4. Neither the true digestibility of nitrogen, nor that of the sum of the amino acids differed between protein sources. 5. True digestibilities of most essential amino acids, considered individually, in sunflower and groundnut meals were similar to or greater than, those of soyabean meal. Exceptionally, lysine was more digestible in soyabean (0.879) than in sunflower (0.722) or groundnut (0.788) meals.

No abstract

Each of four littermate male pigs of 25 kg liveweight was surgically adapted to create a bypass of the large intestine by ileo-rectal anastomosis. The large intestine was sealed at both ends and a cannula was exteriorised from the lumen to allow any products of residual fermentation to escape. Ileal digesta were excreted via the anus. Three isonitrogenous diets were formulated containing soya-bean or groundnut (dehulled) or sunflower (not dehulled) meals as the sole protein sources. Each diet was fed, in turn, for 7 consecutive days to all pigs, and ileal digesta from feeds on days 5 and 6 (indicated by chromic oxide addition to feeds) were collected. This procedure was conducted twice for each diet. Apparent digestibility coefficients (AD) of nitrogen (N) and amino acids were calculated (as percentages of the respective intake). A D of N and the majority of amino acids of soya-bean and groundnut meals were greater (P<0.05) than those of sunflower meal. In the order soya-bean, groundnut and sunflower meal, coefficients were: for lysine, 87.7, 83.5, 71.0% (standard error of the differences between means (SED) 1-06); for threonine, 81.0, 80.5, 74.4% (SED 1-03); for methionine, 89.1, 84.9, 88.5% (SED 0.49); and for the sum of the amino acids, 85.4, 88.1, 78.8% (SED 0.75).