title: Dietary antibiotic growth promoters enhance the bioavailability of alpha-tocopheryl acetate in broilers by altering lipid absorption.
abstract: The influence of intestinal microbial bile salt deconjugation on absorption of fatty acids and alpha- and gamma-tocopherol was investigated in a trial with Ross 208 broilers. Birds (n = 1600) were assigned to 4 dietary treatments: no supplementation or supplementation of antibiotics (salinomycin, 40 mg/kg feed and avilamycin, 10 mg/kg feed), and inclusion of either animal fat (10 g/100 g feed) or soybean oil (10 g/100 g feed) in the diet. At d 7, 14, 21, and 35 of age, the intestinal number of the bile salt hydrolase-active bacteria Clostridium perfringens, the concentration of conjugated and unconjugated bile salts, the ileal absorption of fatty acids and tocopherols, and the blood plasma concentrations of tocopherols were measured. All variables were significantly influenced by bird age. C. perfringens counts were lower and bile salt concentrations were greater in birds fed soybean oil. The supplementation of antibiotics reduced the numbers of C. perfringens in the small intestine and reduced the concentration of unconjugated bile salts. The ileal absorption of fatty acids and alpha-tocopherol, as well as the plasma concentration of alpha-tocopherol, was greater in birds fed antibiotics. The absorption and plasma concentration of gamma-tocopherol were not influenced by antibiotics. Unlike gamma-tocopherol, which is present solely as the free alcohol, the major proportion of dietary alpha-tocopherol is present as alpha-tocopheryl acetate, which requires a bile salt-dependent enzymatic hydrolysis before absorption. In conclusion, proper digestion of lipid-soluble compounds is highly dependent on an adequate concentration of bile salts in the small intestine to provide proper lipid emulsification and activation of lipolytic enzymes.
authors.affiliation: Department of Animal Nutrition and Physiology, Danish Institute of Agricultural Sciences, Research Centre Foulum, DK-8830 Tjele, Denmark.
authors.forename: Ane
authors.initials: A
authors.lastname: Knarreborg
authors.forename: Charlotte
authors.initials: C
authors.lastname: Lauridsen
authors.forename: Ricarda M
authors.initials: RM
authors.lastname: Engberg
authors.forename: Søren K
authors.initials: SK
authors.lastname: Jensen
mesh_terms: D000375:Aging / Q000378:metabolism; D000581:Amidohydrolases / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001647:Bile Acids and Salts / Q000378:metabolism; D001682:Biological Availability; D043182:Carboxylesterase / Q000378:metabolism; D002645:Chickens; D003016:Clostridium perfringens / Q000201:enzymology / Q000302:isolation & purification; D015169:Colony Count, Microbial; D004032:Diet; D005227:Fatty Acids / Q000378:metabolism; D007082:Ileum / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects; D007422:Intestines / Q000382:microbiology; D008049:Lipase / Q000378:metabolism; D009844:Oligosaccharides / Q000008:administration & dosage*; D011714:Pyrans / Q000008:administration & dosage*; D024505:Tocopherols / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics; D024502:alpha-Tocopherol / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D000095662:Polyether Polyketides
chemical_list: D000581:Amidohydrolases; D000900:Anti-Bacterial Agents; D001647:Bile Acids and Salts; D043182:Carboxylesterase; D005227:Fatty Acids; D008049:Lipase; D009844:Oligosaccharides; D011714:Pyrans; D024505:Tocopherols; D024502:alpha-Tocopherol; C010327:salinomycin; D000095662:Polyether Polyketides; C006653:avilamycin; C023154:choloylglycine hydrolase