title: Attenuation of a drug-sensitive strain of a turkey protozoan parasite Eimeria meleagrimitis by selection for precocious development.
abstract: An attenuated line of Eimeria meleagrimitis was established by repeated propagation of the parasite in 9-day old turkey poults and subsequent selection for precocious development. Following 20 passages, the prepatent period decreased from 120 to 104h. A series of experiments were conducted to evaluate the pathogenicity, immunogenicity and fecundity of the newly selected line. Judged by body weight gain, feed consumption and feed efficiency following infection, the attenuated line had appreciably reduced pathogenicity. Immunogenicity of the attenuated line was examined by infecting poults successively with incremental doses of 10(2), 10(3) and 10(4) oocysts at 0, 7, and 14 days of age respectively. No oocysts were detected following challenge with 5×10(2) oocysts, indicating that the attenuated line had retained immunogenicity. Fecundity was assessed by infecting two-week old birds with 5×10(2) oocysts of either parent or attenuated line. Oocyst production from 96 to 240h post-infection showed that the patent period of the attenuated line commenced earlier and was of shorter duration than the parent line.
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States. Electronic address: thilak.rathinam@outlook.com.
authors.forename: T
authors.initials: T
authors.lastname: Rathinam
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States.
authors.forename: U
authors.initials: U
authors.lastname: Gadde
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States.
authors.forename: H D
authors.initials: HD
authors.lastname: Chapman
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D004539:Eimeria / Q000187:drug effects* / Q000276:immunology* / Q000472:pathogenicity; D005243:Feces / Q000469:parasitology; D005260:Female; D005298:Fertility; D011201:Poultry Diseases / Q000188:drug therapy / Q000469:parasitology* / Q000517:prevention & control; D016052:Protozoan Vaccines; D011897:Random Allocation; D012692:Serial Passage / Q000662:veterinary; D014422:Turkeys / Q000469:parasitology*; D014613:Vaccines, Attenuated
chemical_list: D016052:Protozoan Vaccines; D014613:Vaccines, Attenuated
keywords: Attenuation; Eimeria meleagrimitis; Immunogenicity; Pathogenicity; Turkey