Site of Injection Crucial to In Ovo Vaccination
Commercial hatchery trial proves viability of site of injection in ovo for optimal flock immunization
RALEIGH, N.C.--How does site of injection affect the immunology of a bird when vaccinated in ovo? This question was addressed at the 2009 Poultry Science Association Meeting where Brett Hopkins, MS, DVM, Ph.D., DACPV, associate director for outcomes research with Pfizer Animal Health, presented data from a large scale commercial hatchery trial comparing the only two commercially available egg injection systems in the United States.
When comparing the accuracy of delivery to the correct site of injection, Hopkins found that Pfizer’s Embrex® Inovoject® System exhibited significantly greater correct in ovo site of vaccine delivery (95.3 percent) as compared with in ovo delivery using Avitech’s ManualJectTM System (52.3 percent).
In conjunction with Chris Williams, MS, Ph.D., director of poultry technical services Pfizer Poultry Health, Hopkins and Williams designed the trial to evaluate the quality of vaccine delivery as measured by site of injection in ovo, noting that the ability to provide protection against disease after hatch begins with the vaccine being delivered to the correct site of injection in the egg.
“Proper vaccination should be the primary criteria used to evaluate an in ovo injection system because uniform vaccine delivery may provide earlier immunity to diseases when performed correctly,” stated Hopkins.
Proper sites of injection were defined as the amnionic sac, subcutaneous injection to the breast, intramuscular injection into the breast or any combination of the previous. Injection and vaccination of the air cell, allantois, yolk sac, a combination of these sites, or no vaccine deposited at all, were classified as improper and therefore provide questionable disease protection.
A 2000 study demonstrates that the efficacy of vaccines delivered in ovo into the amnion or embryo is greater than 90 percent, regardless of day of injection and breeder flock type ,while vaccines delivered in ovo via the allantois or air cell are less than 50 percent effective in providing disease protection.
“Application of the vaccine in other areas of the egg has also been shown to greatly reduce the protective index against disease challenges,” said Hopkins.
Comparison of In Ovo Vaccine Delivery Systems By Injection Site
Table 1: In ovo system vaccine delivery categorized by injection site - AC (air cell), AC/comb (air cell plus any other combination of injection sites), ALL (Allantois), ALL/AM (Allantois/Amnion), ALL/comb (Allantois plus any other combination of injection sites other than amnion), AM (Amnion), AM/comb (amnion plus any other combination of injection sites other than allantois), EMB (embryo), YS (yolk sac)
Comparison of In Ovo Vaccine Delivery
Overall, the Inovoject System performed 871 total injections to eggs with viable embryos while the ManualJect System injected 930 eggs with viable embryos. Of those 871 viable eggs injected by the Inovoject System, 830 or 95.3% were performed at the proper site of injection. The ManualJect System delivered only 486 or only 52.3% at the proper site of injection.
Comparing the different injection sites occurring in good eggs, the Inovoject System injected 730 eggs in the amnion and 95 in the embryo, classifying them as proper injections. In comparison, the ManualJect System had only 336 amniotic injections and 135 embryonic injections, followed by 185 combination injections occurring in the allantois and amnion, which is considered an improper injection.
This study uncovers a primary question of concern when injecting in ovo: Why should producers be concerned about where a vaccine is delivered? Vaccine delivery is critical to an embryo’s integrity and survival and its proper immunization for protection against disease challenges.
“Conducting large scale evaluations in a commercial setting such as this, establishes relative value and importance of proper in ovo injection for our customers,” stated Hopkins. “The objective of this trial was to reassert the importance of site of injection in ovo and its vital role in providing early, effective and uniform protection against disease.”
The Poultry Health Division of Pfizer Animal Health is a leading provider of innovative, high-performance poultry health solutions to the global poultry industry. Built upon the combined strength and experience of Embrex and Pfizer Animal Health, the Pfizer Poultry Health is committed to developing and marketing commercially novel vaccine, mechanical and data management products which continue to provide increasing value to the global poultry health industry. For more information about the Pfizer Poultry Health, visit us online at www.pfizerpoultryhealth.com.