食物繊維および蛋白質レベルの蛋白質吸収消化率に及ぼす影響

Abstract

The effects of dietary fiber and protein levels on the digestibility of protein by rats were studied. Young rats were fed either 18% or 40% casein diets containing 5% guar gum or else 4%, 10%, or 20% cellulose for 7, 10, or 15 weeks. Nitrogen intake in rats fed the 40% casein diets was about twice that of rats fed the 18% casein diets, but the fecal N did not increase proportionally with N intake. The apparent protein digestibility in rats fed the 18% casein diets containing 5% guar gum or 20% cellulose was significantly lower than that in_??_ rats fed the 18% casein diet containing 4% cellulose, but with the 40% casein diet much dietary fiber did not decrease protein digestion much. The true digestibility was calculated from the metabolic fecal N, which were derived by extraporation to the y-axis a line relating fecal N in the diets containing 18% and 40% casein. The y-axis represented zero N intake. The true digestibility of casein in the 4% cellulose diet was changed little by its level, but with much dietary fiber the true digestibility of casein was lower at a low protein level than at a high protein level.