A HIGH AMYLOSE (AMYLOMAIZE) STARCH RAISES PROXIMAL LARGE-BOWEL STARCHAND INCREASES COLON LENGTH IN PIGS

Young male pigs consumed a diet of fatty minced beef, safflower oil, s kim milk powder, sucrose, cornstarch and wheat bran, Starch provided 5 0% of total daily energy either as low amylose cornstarch, high amylos e (amylomaize) cornstarch or as a 50/50 mixture of corn and high amylo se starch. Neither feed intake nor body weight gain as affected by die tary starch. Final plasma cholesterol concentrations were significantl y higher than initial values in pigs fed the 50/50 mixture of corn and high amylose starch, Biliary concentrations of lithocholate and deoxy cholate were lower in pigs fed high amylose starch. Large bowel length correlated positively with the dietary content of high amylose starch . Concentrations of butyrate in portal venous plasma were significantl y lower in pigs fed high amylose starch than in those fed cornstarch. Neither large bower digesta mass nor the concentrations of total or in dividual volatile fatty acids were affected by diet. However, the pool of propionate in the proximal colon and the concentration of propiona te in feces were higher in pigs fed amylose starch. Concentrations of starch were uniformly low along the large bowel and were unaffected by starch type. In pigs with cecal cannula, digesta starch concentration s were higher with high amylose starch than with cornstarch. Electron micrographic examination of high amylose starch granules from these an imals showed etching patterns similar to those of granules obtained fr om human ileostomy effluent, It appears that high amylose starch contr ibutes to large bowel bacterial fermentation in the pig but that its u tilization may be relatively rapid.