Breeder E. coli vaccination boosts broiler health

Vaccination of broiler breeders against Escherichia coli helps improve the health of their progeny, reports a veterinarian in South Africa.

Although E.coli is ubiquitous in the environment and part of the normal gut flora in chickens, some serotypes of the bacterium can cause serious extra-intestinal infections, especially in chickens that become immunocompromised due to stress, Fambies van Biljon, DVM, of Sovereign Foods, South Africa, told Poultry Health Today.

E. coli infection can lead to a variety of problems such as peritonitis and salpingitis, increased mortality or cellulitis that leads to increased condemnations.

Van Biljon cited a study conducted at Sovereign Foods demonstrating that E. coli vaccination lowered mortality in broiler breeders in lay by about 2.7% at 60 weeks.¹ “This was mainly due to reduction in mortality due to peritonitis from 28% to 15% of total mortality,” he explained.

In chicks from the vaccinated breeders, mortality at 7 days was 1.18%, compared to 1.44% for chicks from unvaccinated breeders, he said. Vaccination was also associated with increased weight gain: chicks from vaccinated birds weighed 188g at 7 days compared to 183g among chicks from unvaccinated birds.

Growing problem

Dionné Rauff, of South Africa’s Deltamune Laboratories, confirmed van Biljon’s impression that transmission of E. coli to broiler chicks is a growing problem in the country. Antibiotics have limited value because mortality tends to occur in the first few days after hatching.

Serotyping of E.coli is uncommon in South Africa, so the prevalence of various strains has not been determined, Rauff noted.

Van Biljon said that for broiler breeders, 22 to 32 weeks of age is a particularly stressful time that increases the chances of E. coli infection. During this time, body weight gain is high and egg production goes from 0% to a peak of about 89%.

In addition, the birds have to adapt to a new environment as they are transferred from the rearing to laying farm. The stress of being stimulated into egg production through increased light exposure and dietary changes puts birds at further risk of E. coli peritonitis and salpingitis, he said.

Broilers, however, can be even more susceptible to E. coli infection because they experience more day-to-day environmental challenges, such as temperature changes, ventilation and dust, van Biljon said. They also face more health challenges, including Mycoplasma and infectious bronchitis.

Method of vaccination critical

Since January 2011, van Biljon has used Poulvac^® E. coli to help protect broiler breeders and their progeny against E. coli infection. The vaccine replaced use of an inactivated E. coli vaccine.

The veterinarian stressed that application of the live vaccine and the frequency of the application are critical to success. Depending on challenge level, vaccination may be repeated during rearing and in lay.

Compared to inactivated vaccines, live vaccines are not only less expensive, but they tend to have no side effects, van Biljon said.

“The reduction in laying mortality has more than paid for the live E. coli vaccine and has resulted in cost savings, with extra day-old chicks in the system,” he said.

Improve antibiotic efficacy

Vaccination is a preventive measure and does not preclude the use of antibiotics to treat birds that become sick, van Biljon said. However, he added that a live E. coli vaccination program can help reduce antibiotic use and thereby maintain efficacy, because resistance can develop when antibiotics are overused or not used correctly.²

He emphasized the importance of using the live vaccine as part of a holistic management strategy. Temperature, ventilation, dust, diet and health issues must be managed carefully to minimize risk of infection. Biosecurity measures must be in place to control other infectious diseases.

Hygiene is critical to reducing the pathogen load in a chicken house after depletion and before placing the next crop, he added. Egg and hatchery hygiene are equally important to reduce transmission of E. coli to chicks, as well as preventing E. coli contamination of water or feed, he said.

1 Abstract for Zoetis E.coli workshop. The use of Poulvac E.coli in an integrated broiler breeder company in South Africa. NJ van Biljon – Sovereign Foods. November 2013 – Madeira.
2 http://mbio.asm.org/content/7/3/e00428-16.full