E. coli is a germ whose presence is inevitable in poultry intestine. It remains benign if the balance between the animal host and its environment is stable, otherwise it can be potentially dangerous. An infection is enough to turn this germ into a mortal disease; the consequences can sometimes be extremely serious in any kind of poultry; turkey, laying hens, chickens. Below are a few simple guidelines and tips which can be implemented on poultry farms in order to manage and, even better, to anticipate imbalances that lead to colibacillosis.
Lower production, reduced feed and water consumption, diarrhea, dehydration, weight loss, mortality! What is happening in our poultry yards? These manifestations might be due to a ‘colibacillosis disease’. Colibacillosis is probably the most frequent and most devastating bacterial infections in avian pathology, leading to high economic losses.
A normal presence of colibacillosis in poultry
Escherichia coli is a commensal bacterium of the digestive tract of poultry. It is a Gram-negative bacterium which is provided with pili. However, only a few serotypes are pathogenic, including "Avian Pathogenic Escherichia Coli" (APEC). Some very specific serotypes are associated with the colibacillosis syndrome in poultry. Colibacillosis results from the transfer of germs of coli bacillus type, from the lower intestinal system to the other digestive or respiratory organs of the animals. These germs end up fixing themselves and develop quickly at the level of these organs. E. coli is housed in the digestive tract of poultry (turkey, chicken, laying hens, chickens) at a rate of 100 000 to 1 million per gram of feces in a balanced flora.
The colonization of one day-old chick’s intestine by colibacillosis must occur rapidly so that the intestinal flora can achieve the right balance. However, some serotypes of E. coli are known to be pathogenic in poultry... But systematic analysis performed on chickens reveal that these same serotypes (or group of microorganisms) often find themselves in totally healthy broiler flocks. However, an E. coli which is known to be non-pathogenic can be found in bird flocks with high mortality rate! It means that the problem is not only due to the E. coli type but also to the animal defenses.
What are the colibacillosis triggers in poultry flocks?
Colibacillosis can affect any type of poultry, turkey, laying hens, chickens. This disease may occur as a result of a temporary decline in immunity. It may be caused either by a virus or poor environmental conditions. One important pathway of the pathogen is the respiratory tract. This comes from the animal having inhaled dust particles contaminated with E. coli. Such particles can stem from the excrements of healthy animals’ digestive tracts. How can this happen? The bacteria multiplies in the upper respiratory tract. The bacteria ends up colonizing the respiratory tracts because of their adhering properties. Then, they manage to reach the blood part and as a result, they proceed to colonize the deeper organs (liver, intestines ...).
However, colibacillary infections do not always lead to diseases. To prevent disease a relative balance must be struck between a regular and favorable E. coli contained in the intestine, and a E. coli contained in the organs or in the overall network of blood circulation. Many factors can actually break this balance. Among these are environmental stresses (cold, heat, ventilation, dust ...), farming mistakes (feed breakdown, vaccine stress, etc.) and viral transfers.
The two main causes that can lead to these negative situations are:
- A heavy-loaded hepatic condition,
- A weak respiratory status.
Depending on the dominant factor, the first element that must be sought is what triggered the stress. Depending on the nature of the problem, the diagnosis can be complemented by a respiratory solution (ventilation, air flows, ammonia or dust), or a liver-oriented type of solution (type of food, age of the animals, etc...).
How can we avoid imbalance situations which are likely to trigger colibacillosis?
The main objective is to avoid physiological imbalance. First, the factors leading to any form of physiological troubles must be examined. These include the frequency of situations where the initial state of imbalance leads to a more serious condition, the age when the issue occurs, the spatial and material locations, and the type of necrosis chart at play.
It is necessary in many cases to use antibiotic therapy, but this option should not be systematic. Systematic use is not necessarily the right way to act because it is important to identify the bacteria's sensitivity to antibiotics to adapt treatment and avoid resistance appearance, which takes time. The objective is therefore to reduce the amount of external interventions by setting up a genuine action plan for preventive control. However, this medical biosecurity strategy is worrying: the repeated use of antibiotics in cases of undefined risk can cause a high exposure and an increased likeliness of resistant strain emergence.
Antibiotic residues require long withdrawal periods and therefore, they limit the commercialization of products (eggs, meat). As for vaccines, not only are they scarce but proof of their effectiveness in farming context is, as of now, far from being convincing. Conversely, the use of complementary and preventive plant-based solutions can avoid the waiting period inherent to antibiotic delivery and the risk of antibiotic resistance.
In order to minimize the risk of colibacillary manifestation in poultry houses, it is essential to rid the respiratory tract of any elements likely to irritate or to weigh on it. At the same time, we must also avoid dealing with the consequences of hepatic hyperactivity, as these can weaken the animals and make them susceptible to bacteriological attacks.
Would you like to reduce colibacillosis manifestations on your farm or to get more information on preventive measures? If so, do not hesitate to contact our experts!