title: Gel-Bead Delivery of Eimeria oocysts protects chickens against coccidiosis.
abstract: Vaccines composed of either virulent or attenuated Eimeria spp. oocysts have been developed as an alternative to medication of feed with ionophore drugs or synthetic chemicals. The purpose of this study was to evaluate the use of gel-beads containing a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts as a vaccine against coccidiosis. Newly hatched chicks (Gallus gallus domesticus) were either sprayed with an aqueous suspension of Eimeria oocysts or were allowed to ingest feed containing Eimeria oocysts-incorporated gel-beads. Control day-old chicks were given an equivalent number of Eimeria oocysts (10(4) total) by oral gavage. After 3 days, chicks were randomly assigned to individual cages, and feces were collected between days 5 and 8 postinfection. All samples were processed for total Eimeria oocysts. At 4 wk of age, all chickens and a control nonimmunized group received a high-dose E acervulina, E maxima, and E. tenella challenge infection. Oocyst excretion by chicks fed gel-beads or inoculated by oral gavage was 10- to 100-fold greater than that of chicks spray-vaccinated with the Eimeria oocysts mixture (log 6.3-6.6 vs. log 4.8). Subsequent protection against challenge as measured by weight gain and feed conversion efficiency was significantly greater (P < 0.05) in gel-bead and oral gavage groups compared with spray-vaccinated or nonimmunized groups. Also, gel-bead and oral gavage groups showed no significant difference (P > 0.05) in weight gain and feed conversion efficiency compared with nonchallenged controls. These findings indicate that incorporation of Eimeria spp. oocysts in gel-beads may represent an effective way to deliver live oocyst vaccines to day-old chicks for preventing subsequent outbreaks of coccidiosis in the field.
authors.affiliation: Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Unites States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA. mark.jenkins@ars.usda.gov
authors.forename: Mark C
authors.initials: MC
authors.lastname: Jenkins
authors.forename: Carolyn
authors.initials: C
authors.lastname: Parker
authors.forename: Spangler
authors.initials: S
authors.lastname: Klopp
authors.forename: Celia
authors.initials: C
authors.lastname: O'Brien
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Miska
authors.forename: Raymond
authors.initials: R
authors.lastname: Fetterer
mesh_terms: D000818:Animals; D002645:Chickens; D003048:Coccidiosis / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D004539:Eimeria / Q000502:physiology*; D016786:Eimeria tenella / Q000276:immunology / Q000502:physiology; D005780:Gelatin / Q000008:administration & dosage / Q000627:therapeutic use*; D033661:Oocysts / Q000502:physiology; D011201:Poultry Diseases / Q000276:immunology / Q000517:prevention & control*; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000276:immunology*; D013045:Species Specificity; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D016052:Protozoan Vaccines; D014613:Vaccines, Attenuated; D005780:Gelatin