Nutritional evaluation of wheat. 5. Disappearance of components in digesta of pigs prepared with two re-entrant cannulae

[Relations between apparent fecal and apparent ileal crude protein digestibility in swine]

The crude protein and lysine digestibility values available in literature and ascertained in comparative investigations at the end of the small intestine (distal ileum) and in the complete digestive tract (faeces analysis method) of pigs were subjected to a correlation calculation in order to find out whether and to what degree there are relations between apparent 'ileal' and apparent 'faecal' digestibility. For both crude protein and lysine the relation between ileal and faecal digestibility is so close (r = 0.73 resp. 0.85 ... 0.98) so that for practical purposes it is not necessary to determine the apparent ileal digestibility for each feedstuff by means of the complicated cannula method. This can be calculated with great reliability from the experimentally ascertained apparent faecal digestibility. The differences between faecal and ileal digestibility are smaller for lysine (conversion factors 0.92 ... 0.99) than for crude protein (conversion factors 0.89 ... 0.93).

Flow of endogenous and exogenous amino acids along the gut of pigs

Digesta were collected from 5 pigs of 33 kg live weight fitted with re-entrant cannulas in the duodenum (within 20-30 cm of the pylorus) and terminal ileum. The pigs received a diet of barley, soya bean oilmeal and a vitamin and mineral mixture. The flow rates of digesta, total nitrogen and the individual amino acids were measured at different time after feeding and during two 24 h periods. A marked increase in the flow of digesta, nitrogen and amino acids was seen in the duodenum after feeding. Total flow during 24 h of nitrogen and amino acids except His, Val, Leu, Phe and Met exceeded intake. Output of nitrogen and amino acids from the duodenal cannula was 117 and 108% of intake, respectively. A method to calculate the ratio of endogenous amino acids in digesta based on the amino acid composition of digesta, diet and endogenous secretions was developed. The calculated amounts of endogenous amino acids passing the proximal duodenum and terminal ileum were 32.2 and 21.9 g per 24 h, respectively. The greatest amount of endogenous amino acids passed through the duodenal cannula in the first two hours after feeding (2-3 g/h) and then gradually decreased to 1 g per hour. The results are discussed in relation to other studies on the secretion of endogenous protein and its amino acid composition.

Availability to pigs of amino acids in cereal grains. 2. Apparent and true ileal availability

1. Pigs prepared with re-entrant ileal cannulas were used to determine the ileal availability of amino acids in nine cereal grains including five wheats, sorghum (Sorghum vulgare Pers.), maize, barley and Triticale. 2. The average true availability of amino acids in these grains was 0.88 but there were consistent differences in availability among amino acids. Generally, lysine and threonine were among the least available amino acids while glutamic acid and arginine were among the most available amino acids in cereal protein. 3. There was much variation in amino acid availability within a grain species (wheat) as among the other grains.

Digestion in the pig between 7 and 3 d of age. 2. The digestion of dry matter and the pH of digesta in pigs given milk and soya-bean proteins

1. In two separate experiments, forty-four pigs weaned at 4--5 d of age were given diets containing milk or soya-bean proteins until slaughtered at 14, 28 or 35 d of age. 2. The retention times of digesta in the stomach and the entire gastro-intestinal tract did not differ between pigs given pelleted diets containing milk or soya-bean protein. 3. Digesta retention times in the stomach were shorter (61 v. 145 min) in pigs given a milk-protein diet in a liquid form than in pigs given the same diet in a pelleted form. The retention times in the whole gastro-intestinal tract were 42 . 8 v. 29 . 6 h on the respective diets. 4. The total retention time of digesta in the gastro-intestinal tract increased with age of pigs between 14--35 d of age when given pelleted diets but not when given a liquid diet. 5. The daily amount of digesta flowing through the anterior small intestine was unaffected by the source of protein. Greater endogenous secretions into the anterior small intestine were observed when pigs were fed ad lib. than when fed at 2 g nitrogen (45 d dry matter (DM)/kg live weight 0 . 75 per d. 6. The apparent digestion of DM to the ileum of pigs given milk, isolated soya-bean protein (ISP) (Promine D) or soya-bean meal (SBM) protein at 28 d of age was 0 . 826, 0 . 825 and 0 . 644 respectively. 7. The apparent digestion of DM to the ileum of pigs given ISP (Supro 610) significantly increased with age of pigs from 0 . 851 at 14 d of age to 0 . 883 at 35 d of age. No increase was observed for pigs given milk protein. 8. Differences in the digestibility of DM between protein sources were greater to the ileum than over the entire gastro-intestinal tract. The greatest increase in DM digestion from the ileum to the faeces occurred in pigs given SBM (0 . 644--0 . 874). 9. Neither the protein source nor age of pigs influenced gastric pH values, the mean value being 4 . 05. pH increased along the small intestine and was not affected by the protein source of age of pig.