Immunosuppression in commercial poultry reduces growth, egg production, and feed efficiency while increasing mortality and treatment costs, creating significant financial losses for farmers. A holistic approach combining biosecurity, vaccination, stress reduction, proper nutrition, and early intervention can help protect flock health and profitability.
- Immunosuppression causes reduced growth, lower egg production, poor feed conversion, and higher mortality in poultry flocks
- Three classic immunosuppressive pathogens in chickens are chicken infectious anemia virus, Marek's disease virus, and IBDV
- Non-infectious factors like stress, malnutrition, mycotoxins, and red mites also compromise immune function
- Young birds are especially vulnerable because the immune system takes 2-6 weeks to fully develop after hatch
- Protection requires biosecurity, vaccination, stress reduction, quality feed, and early intervention when problems are identified
Immunosuppression in commercial poultry can reduce growth, egg production and feed efficiency while raising mortality and treatment costs, making it a hidden drain on poultry profitability.
“Immunosuppression translates into lost performance for the host and the farmer,” Dr. Silke Rautenschlein, head of the Clinic for Poultry at the University of Veterinary Medicine Hannover, Germany, said an October 20 WATTPoultry webinar sponsored by Boehringer Ingelheim.
Performance losses add up
Immunosuppression is a reduced activation or efficacy of the immune system and can be either transient or permanent. Rautenschlein likens a healthy immune system to “a very balanced orchestra,” in which disruption to one participant affects the rest.
“If you affect one participant of the orchestra, the violin or, in our case, the macrophage, then other factors are also compromised subsequently,” she said.
In the field, the greatest concern is often not the response to the original insult but a weakened response to secondary pathogens. For example, bacteria such as E. coli, which may cause little harm in a healthy bird, can take hold in an immunosuppressed one. Vaccine failure and tumors are also risks.
Producers may see reduced growth, uneven flock size, poorer feed conversion, lower egg production or egg quality and higher morbidity and mortality when immunosuppression occurs. Financial losses come from reduced marketable meat, extra feed, veterinary and medication costs and higher contamination at processing.
Infectious and non-infectious causes
Chicken infectious anemia virus, Marek’s disease virus and IBDV are the three classic immunosuppressive pathogens in chickens. Co-infections can worsen outcomes.
Non-infectious factors also contribute. Stress from transport, heat, overcrowding and temperature swings raises corticosterone, which affects immune cells and can shrink lymphoid organs.
Malnutrition or overnutrition, mycotoxins and red mites can also compromise immunity. Red mite saliva contains immunosuppressive components, she said, because parasites are built to avoid killing their hosts.
Age and genotype matter as well. The immune system takes two to six weeks to develop fully after hatch, leaving young birds especially vulnerable.
A holistic approach to protection
Rautenschlein recommends combining biosecurity, all-in/all-out management, downtime and insect control with vaccination matched to flock health, age and local field pressure. Maternally derived immunity, particularly against chicken infectious anemia virus, depends on parent-flock health and good hatchery practices. High-quality feed, avoiding toxins in feed, water and bedding, stress reduction, attention to light quality and early support for a healthy gut microbiota round out the approach.
When a problem is identified, speed matters.
“We have to act early and as aggressively as possible to really reduce the economic losses,” she said.
To register for upcoming webinars or see On-Demand webinars on related topics, visit: www.wattpoultry.com/webinars.
