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24 Feb 2023

Coccidiosis: Understanding the link with intestinal integrity

The correct control of coccidiosis is still the most contentious point in maintaining intestinal integrity, despite the numerous alternative products and vaccines used in the poultry market. As a consequence of the almost always overlapping action of coccidia, intestinal health is affected by bacterial intervention on mucosal cells. Clostridium, salmonella, and the coccidia themselves form one of the trios that currently complicate intestinal integrity, especially when working in a phase of reducing the use of antibiotics.

It is necessary to consider the interactions that occur in the intestine, which can allow coccidia to grow, favoring the damage of epithelial cells, the subsequent increase in the production of cytokines, and later the affectation of mucus-producing goblet cells—developing a process of necrotic enteritis.

Today, the changes that are taking place in the preferences of consumers and large distribution chains put pressure on poultry producers to eliminate the use of antibiotics.

There has been an increase in the number of flocks of birds with alterations in their intestinal integrity that has made the poultry industry investigate more and more alternative products that solve the dysbiosis produced. The different pathogenic species of Eimeria infect several locations in the birds’ intestine, which will decrease their growth or even result in the bird’s death.

Different research papers indicate that the main species of coccidia, such as E. acervulina, E. tenella, and E. maxima, especially the latter, strongly influence the possible colonization of salmonella spp. Research has also shown that necrotic enteritis does not necessarily predispose to further colonization by salmonella spp., and when E. tenella is controlled, the colonization of Salmonella Heidelberg is significantly lower –Hofacre,2007 J Appl Poult Res.–

It is known that using coccidia vaccines influences intestinal integrity even if they are attenuated.

The necessary replication that parasites have to have to produce the desired immunity can sometimes result in significant damage to mucosal cells, especially E. maxima, and favor the action of clostridia, which can lead to a dysbacteriosis at least, which usually requires treatment to return to intestinal normality. An advantage of using the coccidia vaccine is that the prevalence of Salmonella in vaccinated broilers has been 17% lower than in coccidiosis-unvaccinated control birds and 16% lower than in treated broilers with ionophores.

From the studies carried out on the flora of the cecum, it is stated that 70% of its bacteria belong to the Clostridiaceae family and 10% to Lactobacillus spp. On the other hand, the study of the rest of the intestinal flora shows that Lactobacillus spp is the most predominant with 70% (lactic acid-producing bacteria), and Clostridium is only represented with 10%. It means the same types of bacteria are present but in very different proportions.

It must also be taken into account that the cecum is the source of many microorganisms of the normal bacterial flora from the small intestine due to retroperistalsis of the intestines. This reverse movement of cecal contents into the small intestine frequently occurs, making good cecal health important to the overall health of a bird’s intestines.

We must remember that the chicken intestine is a complex organ made up of a balance of bacteria, viruses, and protozoa. When a pathogen such as coccidia upsets this delicate balance, the normal bacterial flora is adversely affected. Pathogenic bacteria may be a small but normal part of the intestinal bacterial flora of a healthy chicken. To prevent them from becoming a more significant part of the normal cecal flora, it is critical that all segments of the intestinal flora can be managed.

The complex ecosystem of the chicken intestine is beginning to be understood, and as our knowledge increases, we will be better able to minimize intestinal disease and have a more efficient growing flock while providing safer and healthier feed for the consumers.