Artificial rearing of pigs. 11. Effect of replacement of dried skim-milk by an isolated soya-bean protein on the performance of the pigs and digestion of protein.
1. Pigs (twenty-one/diet) were weaned at 2 d of age and given liquid diets (200 g dry matter/l) at hourly intervals during a 26 d experiment. The pigs were fed on a scale based on live weight. The diets contained (g/kg DM): dried skim-milk 730 (diet A), dried whey 508.5, isolated soya-bean protein 218, DL-methionine 3.5 (diet S), and soya-bean oil 270 (diets A and S). Diet T contained equal proportions of diets A and S. Soya-bean supplied 0, 370 and 740 g crude protein (nitrogen x 6.25) kg total crude protein in diets A, T and S respectively. 2. Performance was similar for both diets A and T (P > 0.05). Pigs given diet S scoured severely, and fourteen died. The survivors grew very poorly. Nitrogen retention (g/d per kg live weight) was greater for diet A compared with diet T (P < 0.01), and decreased with age (P < 0.001). 3. Protein digestion was examined in the pigs killed at 28 d of age. The amount of soya-bean protein in the diet did not affect the amount of digesta in the stomach, but soya-bean protein decreased the pH, DM and total N content of the digesta (P < 0.01), and increased, though not significantly (P > 0.05), pepsin activity in the digesta and stomach tissue. Acid secretion into the stomach appeared to be enhanced in pigs given a diet containing soya-bean protein. 4. Amounts of trypsin, chymotrypsin, total N and proportion of non-protein-N in the digesta from the small intestine were similar for both diets A and T. The amounts for both diets were greater in the distal compared with the proximal region of the small intestine (P < 0.05). Chymotrypsin activity in the pancreas was reduced (P < 0.05) in pigs given diet T, although this reduction did not seem to impair digestion in 28-d-old pigs. Trypsin activity in the pancreas was similar for both diets A and T. 5. It seems likely that the neonatal pig does not have the digestive capacity to tolerate the large daily intakes of soya-bean protein when dried skim-milk was totally replaced in the diet (diet S). When half the dried skim-milk was replaced, protein digestion was not impaired in 28-d-old pigs.
D000818:Animals; D004044:Dietary Proteins / Q000378:metabolism / Q000494:pharmacology*; D004063:Digestion / Q000187:drug effects*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism; D008297:Male; D008894:Milk Proteins / Q000494:pharmacology; D009584:Nitrogen / Q000378:metabolism; D014674:Plant Proteins, Dietary / Q000378:metabolism / Q000494:pharmacology*; D013025:Glycine max; D013552:Swine / Q000254:growth & development* / Q000378:metabolism
D004044:Dietary Proteins; D008894:Milk Proteins; D014674:Plant Proteins, Dietary; D009584:Nitrogen