Salivary glands are organs in pigs that produce saliva into the oral cavity. As accessory organs of the digestive system, they play a role in initial food processing. They prepare food for digestion and absorption.
Major Salivary Glands and Their Locations
Pigs have several major salivary glands in distinct regions of the head and neck.
The parotid gland, the largest, is located bilaterally, in front of and below the ear. It lies between the ramus of the mandible and the sternocleidomastoid muscle, extending towards the cheek. Its secretions enter the mouth via the parotid duct (Stensen’s duct), opening on the cheek wall near the upper second molar.
The submandibular gland, also called the mandibular gland, is located below the mandible (lower jawbone). It rests superficial to the suprahyoid and infrahyoid muscle groups and can be partially covered by the inferior portion of the parotid gland. This gland is pear-shaped and positioned inferoposterior to the angle of the mandible. Its secretions enter the mouth via Wharton’s duct, which opens at the sublingual papilla, located under the tongue.
The sublingual glands, the smallest of the major salivary glands, are located beneath the floor of the mouth. They lie on the mylohyoid muscle and are covered by the mucosa of the floor of the mouth, forming a raised sublingual fold. Unlike other major glands, the sublingual gland has multiple small ducts, including a major sublingual duct and several minor sublingual ducts, which open along the sublingual folds.
Functions of Pig Saliva
Saliva serves multiple purposes in a pig’s digestive process and oral health. It lubricates, moistening food particles and aiding bolus formation for easier chewing and swallowing. The amount of mucus in saliva adjusts based on the dryness of the consumed food, with more mucus secreted for dry diets.
Saliva also initiates chemical digestion. It contains amylase, an enzyme that breaks down carbohydrates, specifically starch, into simpler sugars like maltose. While the contribution of salivary enzymes to digestion is minor, it marks the first step in the chemical breakdown of food. Beyond digestion, saliva dissolves food components for taste perception. It also cleanses the mouth, protecting against microorganisms.
Significance of Pig Salivary Gland Knowledge
Understanding pig salivary glands is important across various fields. In veterinary medicine, this knowledge aids in diagnosing and treating salivary gland disorders, such as inflammation or blockages, and in performing surgical procedures in the head and neck region. Analyzing pig saliva can offer a non-invasive method for detecting diseases and monitoring the animal’s physiological status, as changes in specific proteins, metabolites, and microbial composition can indicate health issues.
For agricultural practices, understanding salivary gland function informs strategies for optimizing feed efficiency and managing animal health in swine production. Saliva analysis can be used to assess stress levels in pigs, for example, by measuring salivary immunoglobulin A (IgA) levels, which can fluctuate with acute stress. Pigs are also used as animal models in biomedical research, particularly for studies related to human salivary gland diseases and for producing therapeutic proteins, highlighting their broader scientific relevance.