title: Transfer of blood urea nitrogen to cecal microbes and nitrogen retention in mature rabbits are increased by dietary fructooligosaccharides.
abstract: To estimate the effect of fructooligosaccharides (FOS) on N utilization, seven mature rabbits were fed a diet containing 5% glucose or FOS for 8 days. During the last 5 days, total feces and urine were collected to measure N levels (Experiment 1). To examine N transfer from the blood to cecal microbes, eight rabbits were fed the same diets as in Experiment 1. After 9 days of feeding, 2 g of glucose or FOS was given orally. Two hours later 20 mg of (15) N-urea was administered via the ear vein, and 1 h later cecal and blood samples were collected (Experiment 2). Urinary N excretion was lowered by FOS feeding (P < 0.05). Total bacterial N and (15) N in the cecum was significantly higher in FOS-fed animals (P < 0.05). Urea N in the cecum was lower in FOS-fed rabbits (P < 0.05). Similarly, (15) N atom % excess of cecal urea N was also lower in FOS-fed rabbits than in glucose-fed rabbits. These results suggest that FOS in the diet increases the transfer of blood urea N to the cecum for bacterial synthesis, thereby increasing N utilization.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
authors.forename: Xiao
authors.initials: X
authors.lastname: Min
authors.forename: Jin
authors.initials: J
authors.lastname: Xiao
authors.forename: Kiyonori
authors.initials: K
authors.lastname: Kawasaki
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.forename: Ei
authors.initials: E
authors.lastname: Sakaguchi
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001806:Blood Urea Nitrogen; D002432:Cecum / Q000382:microbiology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D009584:Nitrogen / Q000378:metabolism*; D009844:Oligosaccharides / Q000008:administration & dosage*; D011817:Rabbits / Q000378:metabolism* / Q000382:microbiology*
chemical_list: D004040:Dietary Carbohydrates; D009844:Oligosaccharides; C116580:fructooligosaccharide; D009584:Nitrogen
keywords: N retention; bacterial N; blood urea; fructooligosaccharides; mature rabbit