Attenuated coccidiosis vaccine may protect broilers from necrotic enteritis - Interpretive Summary

Necrotic enteritis (NE) can strike young birds seemingly out of nowhere. The disease, which is driven by bacteria and marked by lesions in the gastrointestinal tract, can lead to massive flock mortality.

Poultry scientists have found that flocks can be predisposed to NE when they are infested with Eimeria spp., a microscopic parasite that can infect cells in the gut. The goal now is to figure out the best combination of therapies, vaccines or feed ingredients to strengthen flocks against the threat of NE.

In a new investigation, researchers based in the Netherlands and Spain tested whether giving broilers a combination of an attenuated coccidiosis vaccine (EVANT^®) and feed additives could protect them from Eimeria spp. infestation and reduce the incidence of NE. They reported their findings recently in the journal Poultry Science^®.

Coccidiosis vaccines target parasites such as Eimeria spp. and have been shown to decrease the number of intestinal lesions that can predispose birds to NE. “These vaccines could be a holistic approach to the control of NE disease and an alternative solution to coccidiostats,” write study authors van Eerden, et al.

Broilers in the recent study were also given dietary supplementation with organic acids like MCFA (mainly lauric acid), SCFA (coated butyrate) or PFA (Phytogenic Feed Additives -essential oils plus benzoic acid-). These additives have been shown to improve overall gut health in poultry and there is evidence they have antimicrobial activity.

The birds were then challenged with the microbes E. maxima, a parasite, and C. perfringens, a bacterium. This immune challenge gave the scientists a good idea of how vaccination along with feed additives could support broilers facing pathogens in the gastrointestinal tract.

The researchers found that coccidiosis vaccination decreased intestinal lesions associated with NE while improving bird performance. This held true with or without the addition of feed additives, but the greatest effect was seen with the addition of MCFA to the diet. The vaccine/MCFA combination decreased intestinal lesions associated with NE in vaccinated animals, compared with all treatment groups.

“Therefore, vaccination with a live attenuated coccidiosis vaccine together with in-feed inclusion of MCFA might be a solution to reduce NE in broilers raised antimicrobial- and coccidiostat-free,” write the study authors.

 

The full paper, titled “Efficacy of an attenuated vaccine against avian coccidiosis in combination with feed additives based on organic acids and essential oils on production performance and intestinal lesions in broilers experimentally challenged with necrotic enteritis,” can be found in Poultry Science^® and online here.

DOI: 0.1016/j.psj.2022.101848