By Dr. Denise Heard
U.S. Poultry & Egg Association
TUCKER, Ga. — During the Spring 2023 Research Competition, the U.S. Poultry & Egg Association and the USPOULTRY Foundation approved and funded seven new and innovative research projects. The research funding was approved by the boards of directors of both organizations, based on recommendations from the Foundation Research Advisory Committee.
Research funded out of the Comprehensive Research Competition and Board Research Initiatives included studies for poultry specific diseases, food safety, animal welfare and breeder management. The following paragraphs serve as a brief synopsis of these projects.
· “DNA Immunization as a Safe and Economical Vaccination Strategy Against Infectious Laryngotracheitis Virus (ILTV) to Enhance Mucosal Protection in Primary Sites of Infection.” University of Georgia.
Control of infectious laryngotracheitis (ILT) by vaccination is a critical step in maintaining healthy and profitable poultry production. Nearly all long-lived poultry in the United States is vaccinated against ILT. Commonly, either a recombinant vaccine of the Herpesvirus of Turkey (HVT) or Fowl pox virus (FPV) vectors or with live attenuated vaccines of the chicken embryo origin or tissue culture origin types are used. However, there are specific drawbacks with each of the current types of ILT vaccines.
The objective of this proposal is to demonstrate that a safe and cost-effective mucosal immunization strategy is effective using adjuvanted DNA plasmids expressing known immunogenic ILTV glycoproteins delivered by calcium phosphate nanoparticles.
· “Use of Qualitative and Quantitative Microbial Data to Determine if Turkey Pre-chill and Post-chill Sampling Are Predictive of Salmonella enterica Contamination in Ground Turkey.” Kansas State University.
The USDA Food Safety and Inspection Service has recently taken great interest in reducing salmonella in poultry, specifically, the newly announced proposed framework to reduce salmonella infections linked to poultry. As their requirements for the poultry industry increase, it is evident that publicly available data to support the industry in responding to this heightened regulatory atmosphere is lacking, especially for the ground turkey industry.
This project seeks to fill a critical gap in data and documentation for the poultry industry, through formally evaluating the relationship between indicator microorganisms and Salmonella at pre-chill and post-chill. Furthermore, it will determine whether this method can accurately predict contamination of Salmonella at final grind, which will enhance the capacity of the turkey industry to respond to regulatory requirements.
· “Investigation into the Contributions of Rooster, Hens and Social Dynamics on the Reduced Hatchability in Broiler Breeders.” Auburn University.
In recent years, reductions in fertility and hatchability of broiler breeder eggs have disrupted the supply of chicks. While this may be due to selected growth traits in this industry and the negative correlation with reproductive characteristics, little is known regarding the impact of selection on the mating behavior of modern commercial broiler breeder flocks.
This project aims to improve our understanding of the social dynamics on mating interactions and determine its impact on fertility and hatchability rates, as well as to further our understanding of the individual roles of the hen and the rooster on declining hatchability rates as the flock ages.
· “Discovery of Novel Anthelmintic Resistance Genes to Reduce Production Loss Caused by Blackhead Disease.” Northwestern University.
Heterakis gallinarum, the vector of the parasitic protozoan Histomonas meleagridis, is a determining factor in the control of Blackhead disease, which causes 80-100% mortality in infected turkeys and 10-20% mortality in infected chickens. Long-term survival and transfer of H. meleagridis between flocks is dependent on the hardiness of the H. gallinarum embryos because these parasitic protozoa survive only a short time in the environment.
Thus, the reduction of Blackhead disease and its associated production losses are dependent on the control of H. gallinarum. The number one barrier to the control of H. gallinarum is the efficacy of approved anthelmintic treatments, specifically the benzimidazole (BZ) fenbendazole (FBZ), which is the only anthelmintic approved for use in poultry. This study will generate the first high-quality assembly of Heterakis gallinarum. Further, novel loci associated with benzimidazole resistance in Heterakis gallinarum will be identified to inform future control strategies and diagnostics.
· “Control of Enterococcus cecorum Through Identifying Its Dynamics of Adaptation to the Chickens and Its Environment.” Mississippi State University.
Enterococcus cecorum (E. cecorum) has been associated mainly with osteomyelitis of the free thoracic vertebra in chickens, vertebral osteoarthritis (colloquially named “kinky back”). However, an important increase in the reports of this bacterium producing systemic lesions and having tropism for cartilages resulting in the presentation of femoral head necrosis and synovitis have been reported in the last three years. These conditions produce a negative impact on the broiler industry because of the economic losses represented by the high mortality and morbidity caused by leg problems impairing the chickens from getting feeders and drinkers. Additionally, bacteria from the genus Enterococcus exhibit high antimicrobial resistance and can contribute to the current bacteria antibiotic resistance problem.
The objectives of this study are to 1) recognize the dynamics of E. cecorum in vertical integrations by the identification and characterization of isolates recovered from breeders, hatcheries and broilers, 2) differentiate nonpathogenic from pathogenic E. cecorum isolates, and 3) identify E. cecorum survival times under different environments, materials and disinfectants.
· “Identifying a New Pre-Harvest Gold Standard Salmonella Sampling Strategy to Predict Salmonella Burden on Broiler and Turkey Flocks Arriving for Processing.” University of Georgia.
Salmonella reduction is a key focus for the broiler and turkey industries. Recent advancements in PCR-based methods have improved our ability to quantify salmonella, but the challenge of reproducibility between samples has demonstrated that former best practice pre-harvest sampling approaches must be reevaluated.
The overall objective of the proposal is to create a sampling strategy utilizing the most consistent method for pre-harvest salmonella screening in broilers and turkeys that best reflects the salmonella burden on birds at pre-scald (i.e., prior to any antimicrobial interventions during processing). In doing so, the research will provide industry with an updated gold standard pre-harvest sampling method for salmonella.
· “Updated Decision Support Tool for Supplemental Heat Requirements in Barn Depopulation During an HPAI Outbreak.” Iowa State University.
Rapid and humane depopulation of birds in barns is a key step in limiting viral load in the environment and subsequent disease spread. Few depopulation options exist for the egg industry. The ventilation shutdown plus
supplemental heat, generally referred to as VSD+, is “permitted in constrained circumstances” and is often the only viable choice in egg production, given limitations in housing arrangement, foam or CO2 availability, or the sheer number of birds that limit use of manual methods. VSD+ requires accurate estimation of the quantity of supplemental heat needed.
How much heat is required is highly variable, depending on outside temperature, building leakage, and bird numbers and strain. This project will provide a decision tool which will be a reliable and accurate means of determining supplemental heat requirements for implementing VSD+.
Dr. Denise Heard is director of research programs with the U.S. Poultry & Egg Association based in Tucker, Ga. She can be reached by e-mail at dheard@uspoultry.org.
