Forsøksdyr: Immunoglobulin response to Syngamus trachea infection in the domestic chicken (Gallus gallus domesticus).

Godkjenningsdato 23.03.2020

Godkjenningsperiode 30.06.2020-01.09.2020

The purpose of this experiment is to characterize avian immune response to infection by the parasitic nematode, Syngamus trachea, in the domestic chicken (Gallus gallus domesticus). S. trachea is a problem in the poultry industry because infection of young chickens can cause symptomatic infection and reduced weight gain. In this study we will determine which immunoglobulin subtype (IgG, IgA or IgY) is elevated due to infection of chickens by S. trachea. We will also monitor plasma concentrations of chicken immunoglobulins throughout the progression of the infection, which will allow us to characterize the role of immunoglobulins in S. trachea infection trajectory.

The results from this experiment are important in their own right and will be published in a scientific journal. The experiment will also be a pilot for a future study that seeks to evaluate the immune response of the house sparrow (Passer domesticus) to S. trachea infection. S. trachea is also prevalent in wild birds and may affect ecological processes by reducing the size of wild bird populations. S. trachea infection has been shown to reduce reproductive success and survival in the house sparrow, and this future study will evaluate how environmental exposure to toxic metals may influence house sparrow immunity to S. trachea. Thus, the planned experiment in chicken will allow us to develop efficient methods for elucidating the consequences of S. trachea infection and to refine avian immunoglobulin quantification methods, so that number of house sparrows required for the future experiment is reduced.

To conduct the current experiment, we will raise five domestic chickens to adulthood in a 3x3x3m room containing enrichment materials within the NTNU animal facility. The chickens will be handled daily by animal handlers to encourage familiarity with people. Once they have reached adulthood, we will induce S. trachea infection by introducing eggs of the parasite orally. We will monitor immunoglobulin levels by taking a small blood sample every 7 days.

S. trachea infection is not typically symptomatic in adult chickens due to their larger respiratory system and stronger immune system. We will, however, monitor them daily for signs of disease or distress using a criteria sheet attached to this application. Disease symptoms, usually found in juvenile chickens, include coughing, sneezing, head shaking, gaping, loss of appetite and anemia. In the unlikely event that the adult chickens develop mild disease symptoms, or appear distressed, we will terminate the experiment immediately.

The experiment will be conducted over a 2-month period, after which the chickens will be euthanized by injection of a lethal dose of Sodium pentobarbitone intraperitoneally by a veterinarian.

We cannot avoid using animals for this experiment because S. trachea requires an avian host to complete its life cycle. We use the domestic chicken as the animal host because adult chickens are typically not harmed by the parasite and chickens are accustomed to, and less stressed by, captivity. We will use five chickens to account for the fact that infection will likely not occur in all individuals.