Applications in in ovo technology

Abstract

By mid-August 1995, 55% of broiler embryos in North America were vaccinated for Marek's disease using the INOVOJECT system, with 201 INOVOJECT machines placed with 16 of the top 25 poultry producers, providing the industry with the capacity to inject in excess of 400 million eggs per month or about 5 billion eggs per annum. In ovo administration of a bursal disease antibody-infectious bursal disease virus (BDA-IBDV) complexed vaccine to specific-pathogen-free (SPF) embryos was safer and more potent than conventional IBDV vaccine alone because it delayed the appearance of bursal lesions, produced no early mortality, produced higher geometric mean antibody titers against IBDV, and generated protective immunity against challenge. In ovo administration of a BDA-IBDV complexed vaccine to broiler embryos generated antibody titers against IBDV sooner than conventional virus vaccinates, and generated protective immunity against challenge Direct DNA injection of plasmid DNA encoding beta-galactosidase into breast muscle in ovo and posthatch was an effective means to achieve both gene transfer and expression, with potential for the development of gene vaccines using plasmids encoding protective antigens from poultry pathogens. In ovo administration of 800 U chicken myelomonocytic growth factor (cMGF), a chicken hematopoietic cytokine for cells of the monocytic-granulocytic lineages, significantly reduced mortality associated with Escherichia coli exposure within the hatcher when compared to PBS controls (6.1 vs 12.4, P < or = 0.05), but not when compared to a yeast expression control. A procedure was developed enabling injection prior to the onset of incubation without compromising embryo viability. This in ovo injection process has opened up the window of embryo development during incubation for intervention, as illustrated by the 100% male phenotype produced in chicks hatching from eggs injected with aromatase inhibitor prior to incubation. These data illustrate some of the in ovo applications presently in use by the poultry industry, and under development or in research at EMBREX.

Comparison ofin ovoand post‐hatch vaccination with particular reference to infectious bursal disease. A review

“…In ovo administration (at embryonation day 18) of IBDV, immune complex vaccine was shown to generate antibodies against IBDV causing protective immunity in both specific pathogen free and broiler embryos (43,46). The same vaccine when administered subcutaneously to one day old chicks resulted in a detectable antibody response (24,43).…”

“…The same vaccine when administered subcutaneously to one day old chicks resulted in a detectable antibody response (24,43). In most studies, it has been clearly indicated that chickens vaccinated as embryos acquire higher antibody levels that are sustained at high levels over the normal broiler's rearing period.…”

“…Ideal vaccines produce complete protection irrespective of the maternal antibody status of chicks when administered either in ovo or on the day of hatch (24,74 to broilers with maternal antibodies (24,43,74). The amount of antibody in the vaccine formula does not neutralize the virus but is sufficient to delay its onset of replication, as compared to the same virus used without antiserum (41).…”

“…In addition to improved safety, the IBDV immune complex vaccine results in enhanced immunity as evidenced by higher antibody titers and/or higher levels of protection following challenge with pathogenic virus strains, when compared to naked virus vaccine (43). Moreover, the infectious virus-antibody complex concept of vaccine development has been tested for avian reovirus (22,23).…”

Cytokines and prevention of infectious diseases in poultry: A review

“…Similarly, birds administered recombinant chicken IFN-g prophylactically before a coccidial challenge were found to have an increased weight gain and decreased oocyst production (Lowenthal et al, 1997;Lillehoj & Choi, 1998). The in ovo injection of recombinant cMGF reduced mortality due to Escherichia coli in the hatcher (Johnston et al, 1995). However, an i.p.…”