Artificial rearing of pigs. 12. Effect of replacement of dried skim-milk by either a soya-protein isolate or concentrate on the performance of the pigs and digestion of protein.
1. Pigs (sixteen/diet) were weaned at 2 d of age and given liquid diets (200 g dry matter/l) during a 26 d experiment. The pigs were fed on a scale based on live weight. Dried skim-milk was the only source of protein in diet U and was partially or totally replaced by a soya-bean isolate (diet B) or a concentrate (diets C and D). Soya-bean protein provided 500, 700 or 350 g/kg total crude protein (nitrogen x 6.25) in diets B, C and D respectively. 2. Performance was similar for diets B and D, but poorer than that of pigs given diet U. The apparent digestibility and retention of N of these diets was similar. Pigs given diet C scoured severely and twelve died. 3. Protein digestion was studied in pigs given diets U, B and D, killed at 28 d of age, at the termination of the feeding experiment. The dry matter content and proportion of N in the digesta in the stomach were reduced in pigs given soya-bean protein. Pepsin concentrations in digesta and stomach tissue were unchanged. 4. The concentrations of trypsin and chymotrypsin in the pancreas were greater in pigs given the soya-bean protein concentrate compared with milk protein, but only the increase in trypsin was significant (P less than 0.01). Digesta from the small intestine of pigs given the soya-bean-protein isolate contained less chymotrypsin (P less than 0.05). There were no differences in the proportion of non-protein-N in the total N in the digesta, suggesting that proteolysis of the milk and soya-bean proteins were equally by 28 d of age.
D000375:Aging; D000818:Animals; D002918:Chymotrypsin / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism*; D004063:Digestion; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000201:enzymology; D008894:Milk Proteins / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D010179:Pancreas / Q000201:enzymology; D010940:Plant Proteins / Q000378:metabolism*; D013025:Glycine max; D013552:Swine / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism
D004044:Dietary Proteins; D008894:Milk Proteins; D010940:Plant Proteins; D002918:Chymotrypsin; D014357:Trypsin; D009584:Nitrogen