Restoration of anticoccidial sensitivity to a commercial broiler chicken facility in Canada.
Poult Sci
; 100(2): 663-674, 2021 Feb.
Article
em En
| MEDLINE
| ID: mdl-33518120
Increasing resistance of Eimeria species to anticoccidial medications is an issue in the broiler chicken industry. Using drug-sensitive strains in live-coccidiosis vaccines has been shown to improve anticoccidial effectiveness in US-based broiler production. In Canada, litter is removed between flocks, which differ from the US industry practice. Thus, we investigated the use of drug-sensitive vaccine strains in a Canadian broiler production facility with suspected anticoccidial resistance. Weekly fecal samples were collected from flocks before, during, and after vaccine seeding to determine oocyst shedding patterns; following the vaccine seeding, OPG counts from similar aged birds were lower than flocks before live-coccidiosis vaccine use. Eimeria species isolates, collected before and after vaccine seeding, were used in 2 anticoccidial sensitivity tests to evaluate their susceptibility to commercially available anticoccidial medications; a low-dose challenge to define parasite replication, and a high-dose challenge to monitor broiler performance. In both experiments, isolates collected after seeding were more susceptible to almost every anticoccidial medication evaluated compared with the isolates collected before seeding. These results demonstrate an improvement in sensitivity to many anticoccidials after the use of live-coccidiosis vaccines at this facility. However, the regulated removal of litter at the end of each flock required under Canadian broiler chicken production management rules could limit the establishment of vaccine-strain Eimeria species in broiler facilities and could shorten the longevity of improved drug sensitivity observed in this study.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças das Aves Domésticas
/
Galinhas
/
Vacinas Protozoárias
/
Coccidiose
/
Coccidiostáticos
/
Eimeria
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Poult Sci
Ano de publicação:
2021
Tipo de documento:
Article