1. Add the vegetable oil to a soup pot over medium heat. Stir in the flour and cook, stirring constantly, until the mixture thickens to a paste and turns medium brown, about 10 minutes. Add the celery, onions and bell peppers and cook until softened, about 5 minutes. Add the chicken stock, turkey meat, Cajun seasoning and bay leaves. Bring to a boil, lower the heat and simmer until the soup thickens slightly, about 30 minutes.
2. Add the file powder, salt, black pepper, cayenne and the oysters with any reserved liquor. Simmer until the mixture thickens slightly, about 5 minutes. Serve over cooked white rice.