title: The effect of commonly used anticoccidials and antibiotics in a subclinical necrotic enteritis model.
abstract: Necrotic enteritis poses an important health risk to broilers. The ionophore anticoccidials lasalocid, salinomycin, maduramicin, narasin and a combination of narasin and nicarbazin were tested in feed for their prophylactic effect on the incidence of necrotic enteritis in a subclinical experimental infection model that uses coccidia as a predisposing factor. In addition, drinking water medication with the antibiotics amoxicillin, tylosin and lincomycin was evaluated as curative treatment in the same experimental model. The minimal inhibitory concentrations (MICs) of all antibiotics and anticoccidials were determined in vitro against 51 Clostridium perfringens strains isolated from broilers. The strains examined appeared uniformly susceptible to lasalocid, maduramicin, narasin, salinomycin, amoxicillin and tylosin, whereas an extended frequency distribution range of MICs for lincomycin was seen, indicating acquired resistance in 36 isolates in the higher range of MICs. Nicarbazin did not inhibit the in vitro growth of the C. perfringens strains even at a concentration of 128 microg/ml. Supplementation of the diet from day 1 onwards with lasalocid, salinomycin, narasin or maduramicin led to a reduction in birds with necrotic enteritis lesions as compared with the non-medicated infected control group. A combination product of narasin and nicarbazin had no significant protective effect. Treatment with amoxicillin, lincomycin and tylosin completely stopped the development of necrotic lesions.
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Research Group Veterinary Public Health and Zoonoses, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Lanckriet
authors.forename: L
authors.initials: L
authors.lastname: Timbermont
authors.forename: M
authors.initials: M
authors.lastname: De Gussem
authors.forename: M
authors.initials: M
authors.lastname: Marien
authors.forename: D
authors.initials: D
authors.lastname: Vancraeynest
authors.forename: F
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: R
authors.initials: R
authors.lastname: Ducatelle
authors.forename: F
authors.initials: F
authors.lastname: Van Immerseel
mesh_terms: D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002645:Chickens; D003015:Clostridium Infections / Q000188:drug therapy / Q000662:veterinary; D003016:Clostridium perfringens / Q000187:drug effects; D003044:Coccidia; D003048:Coccidiosis / Q000150:complications / Q000453:epidemiology / Q000662:veterinary*; D003049:Coccidiostats / Q000627:therapeutic use*; D004195:Disease Models, Animal; D024881:Drug Resistance, Bacterial; D004751:Enteritis / Q000188:drug therapy / Q000209:etiology / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D005503:Food Additives / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests; D009336:Necrosis; D011201:Poultry Diseases / Q000209:etiology / Q000517:prevention & control*
chemical_list: D000900:Anti-Bacterial Agents; D003049:Coccidiostats; D005503:Food Additives