Coccidiosis, intestinal health and their relationship to pathogen loads of harvested broilers

For more than 60 years, antibiotics and synthetic anticoccidials have teamed up to keep coccidiosis under control and produce least-cost meat, said Donald Waldrip, DVM, senior technical services veterinarian with Zoetis.

Now, with some poultry companies reducing or eliminating the use of ionophores — a type of antibiotic — there’s more pressure on the synthetic anticoccidials. Producers therefore need to be more cognizant of rotation patterns.

Food safety has also become a greater concern. “We know animals that aren’t treated with antibiotics [may] carry a higher bacteria load. When they enter the processing plant with higher bacteria numbers, the carcass at the end has more bacteria on it,” Waldrip told Poultry Health Today.

“One of the first bacteria mentioned in conjunction with antibiotic-free (ABF) production is Salmonella,” he added.

Higher bacteria load

Larger loads of bacteria in ABF production frequently signal an increase in the amount of Salmonella found in the environment and on the birds, as well as in the intestinal tract during processing.

The presence of large number of coccidia in the intestinal tract also contributes to a thinner, more fragile tract. According to Waldrip, not only is the intestine more easily ruptured during processing, it also exhibits increased porosity due to cellular damage by the cocci. This porosity allows the bacteria to leak through the intestinal tract and travel to other parts of the body spreading bacteria — frequently Salmonella — to the carcass as well as additional products on the processing line.

Researchers and veterinarians are studying Salmonella and exploring ways to reduce its transmission.

In the paper, “Salmonella intervention strategies on the farm,” the late Scott M. Russell, PhD, University of Georgia, noted that Salmonella spreads through vertical as well as environmental transmission in broilers. Some take-away points from his paper:

Salmonella and the environment

• Found at high levels in litter
• Transferred to birds by rodents, wild birds and insects including beetles and flies

Salmonella and breeding stock

• Spread between birds in the breeder barn
• Spread through semen in artificial and live breeding
• Spread through infected eggshells at hatch
• Spread to grow-out houses on delivery through incoming chick paper pads

Salmonella interventions

• Colonize of bird’s intestines with good bacteria
• Use competitive-exclusion products starches such as isomaltooligosaccharide (IMO)
• Vaccinate breeding stock and broiler chicks when the serotype in the vaccine closely matches the serotype found in a portion of the year’s flock
• Acidify drinking water prior to feed withdrawal to reduce the spread of Salmonella during processing