Biotin supply by large bowel bacteria in minipigs: evidence from intracaecal avidin.
The influence of a change of colonic availability of biotin on biotin status was studied. This was done by inhibition of biotin absorption by intracaecal avidin infusion. Five adult minipigs with a permanent caecal 'T' cannula were fed on a semi-synthetic, biotin-deficient diet for 4 months. Following an 8-week adaptation period there were nine sequential 1-week infusion periods with or without oral lactulose or antibiotics. Avidin infusion during weeks 2, 5 and 8 amounted to 18 mg/d (13 U/mg). Plasma biotin concentrations were not changed by avidin infusions. There was a significant average 84% rise in faecal biotin excretion during the avidin periods. Urinary biotin output following avidin decreased by 21%. This is taken as evidence that biotin synthesized by colonic bacteria is available for host metabolism. A rough estimate shows that under basal conditions 1.7-17% of the metabolic allowance may be covered by this metabolic route.
Scholtissek
J
J
Bundesanstalt für Milchforschung, Kiel, Federal Republic of Germany.
Barth
C A
CA
Hagemeister
H
H
Frigg
M
M
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001360:Avidin / Q000008:administration & dosage / Q000494:pharmacology; D001419:Bacteria / Q000378:metabolism; D001710:Biotin / Q000096:biosynthesis* / Q000378:metabolism; D003106:Colon / Q000378:metabolism / Q000382:microbiology*; D004032:Diet; D007408:Intestinal Absorption / Q000187:drug effects; D008297:Male; D013552:Swine; D013556:Swine, Miniature / Q000378:metabolism / Q000382:microbiology*
D001360:Avidin; D001710:Biotin