title: Influence of in-feed zinc bacitracin and tiamulin treatment on experimental avian intestinal spirochaetosis caused by Brachyspira intermedia.
abstract: Thirty individually caged layer hens were inoculated with Brachyspira intermedia, and 20 control birds remained unchallenged. Birds received a diet containing 100 parts/10(6) zinc bacitracin (ZnB), and were monitored for 10 weeks. B. intermedia was recovered sporadically from five of the inoculated birds, and there were no significant effects on body weight, faecal water or egg production. ZnB was presumed to be indirectly inhibiting spirochaete growth, and when removed from the diet, 18 of the 30 inoculated birds rapidly became culture positive. After 4 weeks, 10 of the 30 infected birds were treated with tiamulin at 25 mg/kg for 5 days, and 10 were returned to the diet containing ZnB. Birds receiving tiamulin became spirochaete negative and maintained their egg production, but re-infection occurred. The other 20 infected birds had a significant drop in egg production, but those receiving ZnB showed a reduced colonization by B. intermedia after 3 weeks.
authors.affiliation: Division of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA 6150, Australia. hampson@numbat.murdoch.edu.au
authors.forename: D J
authors.initials: DJ
authors.lastname: Hampson
authors.forename: S L
authors.initials: SL
authors.lastname: Oxberry
authors.forename: C P
authors.initials: CP
authors.lastname: Stephens
mesh_terms: D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000494:pharmacology; D001414:Bacitracin / Q000008:administration & dosage* / Q000494:pharmacology; D002432:Cecum / Q000382:microbiology / Q000473:pathology; D002645:Chickens; D004224:Diterpenes / Q000008:administration & dosage* / Q000494:pharmacology; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005260:Female; D010058:Oviposition / Q000187:drug effects; D011201:Poultry Diseases / Q000188:drug therapy / Q000517:prevention & control*; D013144:Spirochaetales / Q000187:drug effects / Q000254:growth & development; D013145:Spirochaetales Infections / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D004224:Diterpenes; D001414:Bacitracin; C014224:tiamulin