Avian Infectious Bronchitis Virus, commonly known as IBV, is a highly contagious viral infection that severely affects poultry, especially chickens, layers, and turkeys. Belonging to the Coronavirus family, this RNA virus demonstrates a particular affinity for the respiratory, renal, and reproductive systems of birds. Given its high pathogenicity and rapid spread within poultry farms, it is essential to take adequate preventive measures to protect the welfare of the birds and obtain the highest productive performance from them.

It is mainly transmitted through direct contact with infected birds, as well as through viral particles that are released into the environment through respiratory secretions and droppings of infected birds. The disease spreads rapidly in poultry populations, especially in environments with high bird densities, such as farms and hatcheries.

It is important to note that IBV does not represent a direct risk to public health or food safety. However, due to its high rate of spread and its economic impact on the poultry industry, avian infectious bronchitis is a major concern for poultry producers.

Why should special attention be paid to the clinical presentations in the renal and reproductive systems of IBV?

Although IBV is mainly associated with a respiratory tract infection characterized by clinical signs such as wheezing, coughing, depression, and serous or caseous exudate in the respiratory tract, it is also a virus with strains that present tropism for the kidneys, testicles, and ovary.

The pathogenesis is based on the entry of the virus and replication in the primary area (usually the respiratory tract), dissemination through the bloodstream and arrival in the reproductive and/or urinary tract.

Specifically at the renal level, IBV can cause direct damage to the kidneys and the main signs observed are depression, ruffled feathers, wet droppings, increased water intake and kidney swelling at necropsy. This clinical picture is usually seen especially in broilers.

On the other hand, in layers and breeders the picture in the reproductive system is more common, it generates a decrease in egg production and quality (loss of pigment and shell quality), yolk material can also be seen in the abdominal cavity. In some cases, cysts can be generated in the left oviduct and this problem can have major repercussions because if it affects rearing and rearing layers, it may not be detected until the laying peak and generate what is called “false layers”. In the most severe cases, the infection can lead to infertility in breeding birds, which has a direct impact on the productivity and general welfare of the birds.

In addition to specific problems with the renal and reproductive systems, the disease can weaken the immune system of birds, making them more susceptible to other infections and secondary diseases.

Since IBV can cause damage to multiple organs and systems vital to poultry production, it is crucial to pay special attention to the early detection of the disease and the implementation of effective preventive measures.

Importance of vaccination against IBV

Given the severity of the disease and its impact on poultry production, it is essential to take preventive measures, and one of the main strategies is vaccination. Infectious bronchitis vaccines are available and recommended for use on poultry farms. These vaccines help stimulate the bird’s immune system and develop a protective response against the virus.

There are different types of vaccines available to protect against IBV, and the choice of the appropriate vaccine depends on various factors, such as the type of birds, the production system, the farm conditions and the circulating strains of the virus in the region.

Vaccination should start from an early age, when birds are most susceptible to infection. In addition, it is essential to follow the manufacturer’s recommended vaccination schedule and ensure that the appropriate doses are administered to ensure optimal protection.

However, there are vaccine failures due to different factors, such as the genetic variability of the virus, inadequate administration of the vaccine, lack of follow-up on the vaccination program, or exposure to viral strains other than those included in the vaccine. Vaccine failures can allow the virus to enter farms and the disease to spread.

Use of immunostimulating pronutrients for the treatment and prevention of IBV

A promising strategy to combat avian infectious bronchitis are immunostimulant pronutrients. They are active principles of botanical origin that induce the functionality of the ribosomes and therefore the increase in protein synthesis, they act by linking and stimulating gene expression.

Immunostimulant pronutrients improve general immunity and the specific immune response created by vaccination. They increase the proliferation of mononuclear cells, the production of cytokines (IL-1, IL-6, TNF-α and IFN-γ), the phagocytic capacity, and leukocyte infiltration in the injured area. It also improves the transcription of some genes related to cytokines and stimulates the response of CD4+ and Th2 cells, in addition to inhibiting the expression of the enzyme thyrokinase and therefore the proliferation of tumor cells.

Specifically in broilers, an assay was carried out to evaluate the antibody titer in eight batches against IBV. Two batches were vaccinated against IBV and supplemented with immunostimulatory pronutrients (in the graph they are represented as T1) and the other six only received vaccination against IBV (in the graph they are represented as T2). The results were the following:

The results confirm that immunostimulatory pronutrients improve the specific response against IBV.

Another trial carried out in laying hens showed very similar results, the animals were divided into three groups: T1 (vaccination against IBV and supplementation with immunostimulant pronutrients 5 days before and 5 days after vaccination), T2 (only vaccination against IBV). and T3 (only vaccination against IBV):

The group supplemented with immunostimulating pronutrients (T1) obtained an antibody titer higher than T2 (+45.15%) and T3 (+22.41%).

The combination of proper vaccination and the use of immunostimulating pronutrients can help to reduce the impact of this disease in birds and minimize the associated economic risks.

Finally, emphasize that there are complementary measures such as biosecurity and cleaning and disinfection, which must always be present in all types of farms for the prevention not only of IBV but also of many other pathogens.

Conclusions

In summary, infectious bronchitis in poultry caused by IBV is a highly contagious disease that affects poultry production. Special attention should be paid to the renal and reproductive systems, as the virus shows tropism for these organs. Adequate vaccination is essential to prevent the disease, although vaccination failures can occur. Immunostimulant pronutrients offer an additional promising strategy to strengthen bird immunity and combat IBV and other diseases. A combination of preventive measures ensures the welfare of the birds and a successful poultry production.

The product based on immunostimulant pronutrients is marketed by Biovet S.A. under the name of Alquernat Immuplus and is available in premix and liquid presentation.