After the food leaves the crop via peristaltic action, it moves into the proventriculus. Also known as the “true stomach”, the proventriculus is where actual digestion begins. The walls of the proventriculus are thick and composed of five layers: a muscle layer, itself composed of three individual layers, a thick layer of glandular tissue, and the inner mucous membrane layer. The glandular tissue produces secretions that begin the process of digestion; these secretions include Hydrochloric acid, which lowers the pH of the digestive system and food mixture, the enzyme Pepsin that helps break down protein, and the hormone Gastrin, which stimulates gastric and pancreatic juice production. The acid and digestive enzymes in the proventriculus break down food more significantly than the enzymes secreted by the salivary glands. At this point, the food has not yet been ground, once softened it moves to the gizzard.
For More Information About Chicken Digestion and Nutrition visit
virtualchicken.com