Infectious bronchitis: using miRNAs to protect egg layers

Authors: Véronique Charreton-Sanford, Dre Neda Barjesteh, Dr. Carl A. Gagnon

CRIPA, Fonds de recherche du Québec, Université de Montréal

Article translated by CRIPA

Article published in La terre de chez nous on May 4, 2023 : https://www.laterre.ca/chroniques/page-de-conseils/bronchite-infectieuse-proteger-la-ponte-doeufs-par-les-miarns/#:~:text=Fausses%20pondeuses,-Chez%20la%20poule&text=Ainsi%2C%20les%20miARNs%20sont%20de,les%20poulaillers%20infect%C3%A9s%20au%20Qu%C3%A9bec.

Infectious bronchitis virus (IBV) is a highly contagious avian coronavirus primarily affecting chickens worldwide. Like the other members of Coronaviridae such as SARS and COVID-19, IBV is a virus with a strong tendency to mutate (1). There are already several variants of the virus, and the constant emergence of new mutations in different countries complicates the development of vaccines.

IBV infection results in infectious bronchitis (IB). For example, sick broilers have difficulty breathing, while laying hens produce fewer eggs due to lesions in their reproductive system or produce eggs with much weaker shells (2). This false egg layer syndrome is a real problem since the absence of production becomes evident only in adult hens, i.e., when the virus is no longer present.

As a disease that leads to complications and high mortality, infectious bronchitis is a major issue for Quebec, which provides more than 20% of Canadian egg production, closely following Ontario (3).

The objective of this research is to identify small molecules known as microRNAs (miRNAs) that could control the spread of IBV.

All the instructions for manufacturing living organisms are contained in very long molecules called DNA. From DNA, "SMS messages" are copied and sent to a "factory" with instructions on manufacturing the materials and tools required to ensure the well-being of the organism. The “SMS messages” are molecules of messenger RNA and the final tools for making proteins (Figure). Viruses such as IBV embed themselves incognito in this messaging system to get their RNA and proteins produced free of charge by animal cells. This is how they multiply.

However, miRNAs are like “anti-SMS” capable of adhering to messenger RNAs and transforming them into “spam emails” thrown directly into the “trash”. Therefore, if we can cause anti-IBV miRNAs to be produced in our pullet cells, then none of the proteins requested in the viral “SMS message” will be created. This could be a way to block exclusively the multiplication of the infectious bronchitis virus.

Refining this strategy could lead to the reduction of the spread of the infectious bronchitis virus. The end result would be to increase animal welfare while reducing economic losses.

Inset

In hens, infection with infectious bronchitis virus (IBV) can cause egg-laying problems that are not detected until adulthood; these birds become false layers. MiRNAs are molecules potentially capable of preventing viral infections like that of IBV. We want to find out if they could be used in prevention and treatment, thus reducing the colossal economic losses in Quebec's infected poultry houses.

Bibliography (Vancouver format)

1. Payne S. Family Coronaviridae. Viruses. 2017;149-58.

2. Morin MEB, Chénier S, Bergeron N. La bronchite infectieuse aviaire au Québec. :7.

3. Stratégies de contrôle de la bronchite infectieuse aviaire dans l’industrie avicole québécoise [Internet]. La Terre de Chez Nous. 2021 [cited 30 sept 2022]. Available on: https://www.laterre.ca/actualites/page-conseils/strategies-de-controle-de-la-bronchite-infectieuse-aviaire-dans-lindustrie-avicola-quebecoise.