MADISON, N.J. — The rise in the prevalence of “no antibiotics” poultry production has been a “life changer” in poultry production, making necessary new approaches in Salmonella control. The days are gone when the processing plant provided the sole or primary interventions against Salmonella in poultry products, and today the use of live production controls is essential in a holistic approach to control Salmonella.
In an interview with Merck Animal Health, Dr. Martha Pulido Landinez, associate clinical professor, Mississippi State University, outlined a 5-point plan for controlling Salmonella across the poultry live production chain.
“The foundation of an effective Salmonella control program,” she said, “is good management of biosecurity and the chicken’s gut health, protecting the chicken’s respiratory system, providing good quality feed and air in the poultry house, and managing the welfare of the chickens. This is the basis for a flock’s general good health, which, in turn, makes more effective the specific disease-control tools such as vaccination for Salmonella.”
A lot is at stake for Salmonella control outcomes, Landinez said. Not only does the presence of Salmonella in chickens pose a risk in terms of public health, but certain Salmonella serotypes — acting as secondary bacterial infections — can cause severe disease and mortality in chickens at one to two weeks of age. And a serious, longer-term public health risk is the potential development of antimicrobial resistance in these bacterial populations.
“It is important to keep Salmonella loads low on our chicken farms,” she explained. “If we do not control Salmonella there, we are not controlling antimicrobial resistance.”
5 live production priorities for Salmonella control
1. Use diagnostics to monitor Salmonella, identifying transitory and resident serotypes on the farm.
2. Keep Salmonella numbers low inside and outside poultry houses, especially during downtimes between flocks.
3. Breeder flocks and hatcheries must be Salmonella free, especially serotypes S. Enteritidis, S. Typhimurium, and S. Heidelberg.
4. Manage the chicken’s gut and the litter ecosystem to protect flocks from Salmonella exposure.
5. Vaccination of chickens is essential for the control of Salmonella in the poultry integration.
5 live production priorities
Landinez recommends five live production priorities for effective control of Salmonella in the poultry production chain.
- 1. Use diagnostics to monitor Salmonella, identifying transitory and resident serotypes on the farm.
“If you don’t know what serotypes are on your farms, you can’t control Salmonella,” she said.
Transitory serotypes are often weaker and removed by cleaning and disinfection. Resident serotypes, on the other hand, are adapted to the environment and the pests (mice, flies, darkling beetles, roundworms, etc.) residing there. Resident serotypes (such as S. Enteritidis, S. Typhimurium, S. Heidelberg) tend to persist for long periods and exhibit exponential growth.
If certain serotypes are identified in consecutive flocks, review the effectiveness of the cleaning and disinfection process, and analyze the vaccination program. Sometimes, it is necessary to use a specific intervention for a specific serotype. Make sure the disinfectant being used is effective for the Salmonella serotype found. Administer the right vaccine for the serotype and type of flock (pullet, breeder, broiler, etc.).
- Keep Salmonella numbers low inside and outside poultry houses, especially during downtimes between flocks.
“The most important way to keep Salmonella numbers low is to take care of the poultry litter’s condition,” she said.
Wet litter is an environment that promotes the growth of Salmonella, and dry, dusty poultry house conditions promote the respiratory spread of Salmonella in chickens.
Poultry litter is an ecosystem in which Salmonella, and other bacteria such as E. coli, along with Salmonella-harboring pests such as mice, flies, darkling beetles, and roundworms, can survive for a long time. It is important to control those pests inside and outside the poultry house, especially during downtime between flocks.
“If we are able to keep the Salmonella numbers low inside the chicken house and outside the chicken house during the downtime period, I am almost sure that we can have very low Salmonella numbers when the chickens are in the chicken house,” she said.
- Breeder flocks and hatcheries must be Salmonella free, especially of the most important serotypes such as S. Enteritidis, S. Typhimurium, and S. Heidelberg.
Grandparent, parent, and breeder flocks must be Salmonella free, because of their connection with hatcheries and broiler flocks. It is critical to work in each sector to decrease the levels of Salmonella being sent to the other sectors.
The work of keeping hatcheries clean of Salmonella is done mainly on the breeder farms by eliminating dirty eggs through quick egg collection and the training of the pullets to use the nests.
Other steps for keeping hatcheries Salmonella free include good cleaning and disinfection and the regular evaluation of the hatchery’s biosecurity system.
- 4. Managing the chicken’s gut and the litter ecosystem is essential for the control of Salmonella throughout the integration.
Good gut health decreases the multiplication of Salmonella bacteria in the chicken’s intestines and reduces its expression through the feces.
Protect chickens from Salmonella exposure, especially during their first 48 hours in the poultry house. Avoid having chickens eat or breathe Salmonella and other bacteria in the litter.
Disrupting Salmonella and other pathogens in the litter ecosystem is important for maintaining the chicken’s gut health. Work in the poultry house environment and the litter to lower bacterial loads in the litter ecosystem.
- High moisture retention (wet litter), caking, bacterial pathogens, and feed spillage can be major causes of increased Salmonella numbers.
- It is important to control pests (rats, mice, flies, darkling beetles, roundworms, etc.) that can be vectors for Salmonella and other pathogens.
- 5. Vaccination of chickens is essential for the control of Salmonella in the poultry integration and its products.
“Salmonella vaccination is the best tool to decrease the risk of foodborne disease related to Salmonella in chicken products,” Landinez said. “Using vaccines decreases the expression of Salmonella in the bird’s intestines and in that way decreases the chance of the presence of Salmonella in the egg or the chicken meat.
“I find people saying that vaccines are not necessary if there is not a challenge close to their farm. I think that kind of thought is a mistake. Protection against the presence of Salmonella is difficult to achieve because there are many potential sources in which there cannot be zero presence of the pathogen,” she said.
Know the serotypes found on your farm or in your poultry operation and decide what vaccine works best for your farm or company.
Live vaccines provide the necessary cellular immune response in all types of chickens, including broilers. But it is essential to have both live and killed Salmonella vaccines in vaccination programs for pullets, breeders, or commercial layers, she said. Killed vaccines provide the long-lasting humoral response necessary in the long-lived birds.
Essentials for a holistic control effect
Mounting an effective holistic Salmonella control program requires commitment at the corporate level and the deployment of resources and effort across the integrated poultry enterprise.
Landinez explained why: “Salmonella is ubiquitous across the integrated poultry production chain, and the chicken’s intestine can work as a Salmonella factory where the bacteria are multiplied. The presence of even one bacterial cell anywhere along the chain can be multiplied exponentially. For that reason, we need to work in each sector of the integration to decrease the quantity of Salmonella being sent to the next sector.”
The presence of Salmonella in poultry operations and chicken products is a problem of the whole chicken meat supply chain, and ‘live side’ interventions, along with processing plant controls, are crucial for Salmonella control in the poultry integration and its products.