Effects of broiler breeder flock age on egg quality, Salmonella maternal antibody transfer, and Salmonella colonization resistance in broiler progeny

Commodities

Practices

Salmonella is a common cause of foodborne disease in humans, and high Salmonella load in commercial and backyard flocks is a challenge that negatively affects poultry production. Broiler breeder Salmonella vaccination programs reduce Salmonella load and induce Salmonella-specific maternal antibody transfer from hen to chick. These antibodies play critical roles in early chick health, but maternal antibody transfer is highly variable and may be influenced by production factors. However, the causes or correlations (like egg quality) of variable maternal antibody transfer in domesticated poultry remain unstudied. By understanding how maternal antibody transfer can be improved, established poultry production practices could be optimized to meet national agriculture initiatives. Therefore, this project will investigate the role of broiler breeder flock age (~35 and ~55 weeks old) on internal and external egg quality and determine how these parameters correlate with maternal antibody levels and Salmonella colonization resistance in progeny. By evaluating hatching egg quality, quantifying Salmonella-specific maternal antibodies in egg and chick, and conducting a live Salmonella challenge, this project will determine if broiler breeder flock age and egg quality affect hatch performance and chick health outcomes. Moreover, this project will contribute to growing evidence that internal and external hatching egg quality may contribute to early chick immunophysiological development. This project will directly support American poultry farmers by optimizing a broiler's physiological processes, reducing Salmonella load, and decreasing associated management costs, therein increasing profit over the long-term and improving quality of life for farmers, farm employees, and their communities.

The proposed project will address three objectives in a two-year timeframe:

1. Evaluate internal and external egg quality parameters and maternal antibody levels in the yolk and albumen of eggs obtained from the same broiler breeder flocks at approximately 35- and 55-weeks old (wo).
2. Quantify Salmonella-specific antibody levels at hatch among chicks obtained from the same broiler breeder flocks at approximately 35- and 55-wo.
3. Determine the protective effects of Salmonella-specific passive immunity at hatch among chicks obtained from the same broiler breeder flocks at approximately 35- and 55-wo after a low- or high-dose live Salmonella challenge.

We hypothesize that egg quality parameters will be altered as a broiler breeder flock ages, which will impact hatch performance, correlate to an egg's maternal-derived antibody content, and influence the capability of Salmonella to colonize newly hatched chicks.