The Anatomy and Physiology of the Monogastric Digestive System of Pigs

Introduction and Important Terminology

The pig has a digestive system which is classified as monogastric, or nonruminant. Humans also have this type of digestive system. They have one stomach (mono = one, gastric = stomach). The monogastric digestive system differs from that of a polygastric (or ruminant) digestive system found in cattle, sheep and goats. These animals have one stomach broken into four compartments. Due to the differences in the digestive systems, ruminants can consume different types of feed than pigs. Cattle, sheep and goats can live on hay and pasture, while pigs must eat grains that can be digested more easily.

Digestion is the breakdown of food occurring along the digestive tract. Digestion includes all processes by which foods in the alimentary canal are prepared for absorption. The digestive tract may be thought of as a long tube through which food passes. As food passes through the digestive tract, it is broken down into smaller and smaller units. These small units of food are absorbed as nutrients or pass out of the body as urine and faeces.

The digestive tract of the pig acts to digest and absorb nutrients necessary for the maintenance of cells and growth. Efficient absorption of nutrients depends on each segment of the digestive system functioning to its maximum capacity.

Important terminology:

• Absorption is the process of taking nutrients from the digestive system into the blood so they can be used in the body
• Anatomy is the study of the body’s (or a part of the body’s structure), in this case, the digestive tract of the pig.
• Carbohydrates are the main nutrient that supplies energy to the body (starch and cellulose).
• Enzymes are substances that speed up chemical reactions within the body.
• Fats are energy nutrients which supply 2.25 times as much energy as carbohydrates.
• Physiology is the study of how the body (or a part of the body) works, in this case, the digestive tract of the pig.

Proteins are the nutrients that supply the building materials from which body tissue and many body regulators are made.

Anatomy of the digestive system of a pig

The digestive tract of the pig has the following main parts:

• The mouth.
• The oesophagus.
• The monogastric stomach.
• The small intestine.
• The large intestine.
• Accessory digestive glands (liver and pancreas).