Recipient Organization
UNIVERSITY OF DELAWARE
(N/A)
NEWARK,DE 19717
Performing Department
Animal and Food Sciences
Non Technical Summary
Vaccination plays a critical role in the health management of poultry production. Numerous economically important infectious diseases are controlled through vaccination. Hatchery spray vaccination of day-old commercial chickens with live vaccines is a common and convenient method. However, the current spray method is not without limitations. Thus, research seeking improvements in hatchery vaccination administration methods is warranted. This research project aims at developing and evaluating an innovative foam-based vaccination technique at poultry hatcheries to improve vaccine efficacy. Foams including vaccines will be produced and spread onto the chicks. The project will focus on accomplishing the following objectives: 1) to investigate and screen the characteristics of foam candidates and the behavior of the chicks when exposed to the foam; 2) to evaluate selected foam candidates on the viability of live vaccines; 3) to develop a foam generation and delivery system for live vaccines under hatchery conditions; and 4) to conduct verification tests using experimental trials in commercial type chickens. The project is expected to develop an understanding of the mechanisms and performance of the foam based mass vaccination administration method for poultry hatcheries and to demonstrate the robustness, simplicity, versatility, and cost-effectiveness of the method. Outcomes of the proposed study will provide research-based information on the application of foam vaccination, improve health and production performance of poultry and keep American agriculture competitive while ending world hunger.The project objectives would address the priority of AFRI foundational program #5: Agriculture Systems and Technology. It fits well into the goals of Engineering Products, and Processes to Improve Agriculturally Relevant Animal and Natural Resource Systems.
Animal Health Component
40%
Research Effort Categories
Basic
30%
Applied
40%
Developmental
30%
Goals / Objectives
The long-term goal of this project is to develop an innovative, effective, and affordable engineering system to improve animal health and production. The project will focus on accomplishing the following objectives:1) To develop a foam generation and delivery system for live vaccines under hatchery conditions;2) To evaluate the effect of foams produced from the prototype systems on virus viability; and3) To verify system performance using experimental trials in commercial type chickens.
Project Methods
Objective 1: To develop full-scale foam generation and delivery systems for live vaccines under hatchery field conditions1.1 Full-scale foam-based mass vaccination administration for hatchery facilitiesBased on the foam selected empirical model developed from the prototype, the two most effective foams from each protein-based and small molecule surfactant-based group will be selected and a full-scale foam vaccination administration system will be designed and developed with considerations of the most influential variables. Three foam generation systems to create foam will be developed: (1) aspirating for high expansion foam, (2) aspirating for medium and low expansion foam, and (3) pressurized aerosol foam. The foam vaccination administration should be similar to the currently used hatchery spray system. In many hatcheries, 100 chicks are placed in a 23.5 L x 18.5 W x 6 H inch plastic tray, which is transported by an automated conveyor system through vaccine coarse spray nozzles. Static cone shape or flat slot scanning type spray systems are used. The typical spray time for one tray varies from 1 to 5 seconds.1.2 Verifying foam characteristics and refining full-scale prototypesThe prototypes will be tested thoroughly with different foam formulations to determine their performances and operation ranges for different parameters. Foams will be produced and tested for their characteristics, such as formability, foam stability, and virus viability. The results will be compared with design parameters and the prototypes will fine-tuned in Objective 2.Objective 2: To evaluate the effect of foams produced from the prototype systems on chick behavior and virus viability2.1 Evaluate effects of foams on chick behaviors and ingestion volumesFoam from the full scale prototype will be further tested with live day-old chicks. The thermal environment, behavior and response of the chicks exposed to the different foams will be measured and quantified. A fluorescent tracing method using fluorescein will used to determine the volume of foam ingested by chicks. First, a calibration curve will be developed to determine the amount of ingested foam by the chicks to the measured reflection signal of the fluorescent. The calibration curve will be generated by gavaging chicks with known volumes of fluorescein water solution. Day-old Cobb 500 chicks from a hatchery will be used and administered a 0.1% fluorescein solution in foam agent at three different volumes (1, 10, 50, 150, 200, 300, 400, and 500 ml) by gavaging. Three chicks will be used per volume. Ten minutes after administering the fluorescein mixtures, the chicks will be euthanized by an approved method and the upper gastrointestinal tract, including esophagus, crop, proventriculus and gizzard, was removed. The removed upper gastrointestinal tract will be placed into an 80-ml Seward filter bag with 1 ml dH2O and double-bagged with a 118-ml black Whirl-Pak bag. The samples will be stomached for 1 min at a speed of 120 rpm and liquid samples in the bags were then placed onto a 96-well polystyrene plate at a 1:2 dilution to determine the optical signal using an absorbance reader (ELx800, Bio-Tek Instruments. Inc., Vermont, USA) at 490 nm excitation level. A standard curve will be created. In each trial, 50 newly hatched chicks will be contained in 50% of the area of a standard plastic chick tray (each tray for 100 chicks) with paper bottom to test the responses of the birds to foams (0.25 to 0.4 g) with different foam temperatures. Fluorescein will be added into the foam agent to create 0.1% concentration. Green food dye will be added to the foam agents and foams will be topically applied to chicks. Foams will be administrated to the chicks trays by the prototypes developed in Objective 1 and compared with coarse spray. A video recording system will be used to capture the behaviors and the response of the chicks exposed to the different treatments over a 10-min period. An ethogram has been developed by our group to analyze the different behaviors using coding software.2.2 Evaluation of the effect of foam candidates on virus viabilityThe prototype will be tested thoroughly with different foam formulations to determine their performances and operation ranges for different parameters. Foams will be produced and tested for their characteristics, such as formability, foam stability, and virus viability. The top two foam candidates selected from Objective 1 for vaccine transport will be evaluated for their effect on the vaccine virus(es). A commercially available IB virus vaccine(s) will be used for the studies as it is routinely applied via spray to baby chicks in the U.S. Favorable foam preparations will be further studied to optimize the prototypes and determine the effect of field prototypes with chicks on virus viability and immune responses.Objective 3: To conduct verification tests using experimental trials in commercial type chickens3.1 Efficacy of vaccines delivered to hatched chicks via novel foam deliveryExperiments will be conducted to demonstrate that immune responses generated in birds after foam vaccination under commercial hatchery conditions. Foam candidates that have favorable properties and do not impact virus viability will be deemed acceptable for in vivo evaluation. Newly hatched chicks will be assigned to treatment groups. The eye-drop control treatment group will be vaccinated according to the manufactures' instructions for ocular instillation. The commercial spray control treatment group will be vaccinated as follows. A standard, 100 capacity chick boxes will be divided in a 60%/40% split. Forty chicks will be placed within the 40% section of the box. One 1,000-dose vaccine vial will be reconstituted in 70mL of distilled water. The chick box will be sprayed with a standard full spray dose of 7 mL in a commercial spray cabinet setup. The foam/vaccine candidates will be applied by the field prototypes developed in Objective 1. Foam application equipment will be cleaned and sanitized between vaccine applications to avoid accidental carryover of vaccine between foam treatments. Chicks will be housed Newark in commercial grow-out conditions and they will be offered feed and water ad libitum. Five days post vaccination (DPV), oro-pharyngeal swabbings will be collected from each bird using a plastic shafted, nylon swab. Each swab will be placed in 2mL of cold, sterile TPB containing 10,000 IU/ml penicillin, 10,000 IU/ml streptomycin, and 250 IU/ml amphotericin B for detection of viral IB vaccine nucleic acid by rRT-PCR (Callison et al., 2006).At 14 DPV, lacrimal excretions and serum will be collected from each chicken and screened by a commercial ELISA kit for the presence of antibodies to the IB vaccine (Gelb et al., 1998). Birds in treatment groups 2 through 8 will be challenged with a homologous live IB virus (104.5EID50/bird) administered via eye-drop. Individual tracheal swabs will be collected 5 days post challenge for virus reisolation attempts in specific pathogen free embryonated chicken eggs (Gelb and Jackwood, 2008). Three, 10-day-old embryos will be inoculated with a given swab sample. A result of one lesion-positive embryo out of three will represent a positive virus isolation (a vaccine failure). Conversely, samples yielding no lesion positive embryos will be considered negative for virus isolation (vaccine successfully induced protection). Tracheas will be evaluated for ciliary activity (Cook et al., 1999). Ciliary activity will be observed with an inverted microscope and scored as; 0, all cilia beating; 1, <100% but >50% of cilia beating; 2, no cilia beating. The average total score for each trachea will be calculated.