The Digestive Tract of a Pig

The small intestine, colon, and one stomach compartment make up the pig's monogastric digestive system. The cardia, body, and pylorus are three distinct pouches that make up the stomach (Colville & Bassert, 2015). The fundus filters food as it travels from the esophagus into the stomach in the first segment, known as the cardia. The body is the expanded sac, which when empty rests in rugae, or folds. The pylorus is the stomach's exit, and its main purposes are to stop large food items from passing through and intestinal contents from backing up. The sphincter muscles act as the gate control, where it allows food to enter and exit the stomach (Vanhorn & Clark, 2011). Like in the mouth, stomach aids physical digestion. The liver produces digestive acids while the gall bladder releases bile, secretions that break down food substances to simple materials that can be acted upon by digestive enzymes.

The next section is small intestine, which is best known for active digestion and absorption of food materials. The tubular organ is characterized by a narrow diameter and is divided into duodenum, jejunum, and ileum (Herren, 2012). The categorization is based on the chemical processes that take place in each section. The small intestine of the pig empties into the colon through caecum, a small pouch that is largely vestigial. The large intestine is divided into descending, transverse, and ascending sections (Vanhorn & Clark, 2011).

The stomach and the intestinal system of the pig are covered with different types of connective tissues. For instance, a thin and transparent lining epithelium called peritoneum covers the entire abdomen. The subsequent mesentery houses the blood vessels and nerves that serve the small intestine (Michael & Michael, 2013). The omentus acts as the cushiony lining of all abdominal organs, where the connective tissue allows the system to withstand shocks (Vanhorn & Clark, 2011). While it is not part of the main frame of the track, the pancreas is also an important secondary organ in the digestive system of pigs. It secretes trypsin, amylase, and lipase, enzymes that play a vital role in the chemical breakdown once they are released into the digestive tract. The liver also supports the digestion, where it produces bile that is conveyed to the gall bladder

Effects of the Physiological Design on the Basic Nutrient Requirements

The most distinctive element of the physiology of the digestive system of a pig is its monogastric nature, where the stomach has only one compartment. The feature makes it impossible to digest large chunks of roughages and causes physical breakdown at the mouth a vital aspect of food intake. The inability to break the plant materials calls for higher concentrates in the rations, where pig feed should be is low in fiber and high in total digestible nutrients (Cooper & Burton, 2014). The animal is non-ruminant, where the small capacity of the stomach can only hold a limited amount of materials at any given time. The bigger proportion of digestion also takes place in the small intestine. The simplicity makes it hard to make vitamins in the digestive system, thus, B-complex vitamins need to be included in the diet (Cooper & Burton, 2014).

Discussion of why the System Evolved and how animals Benefit from the Design

Like in the case of human beings, pigs represent the primitive condition of ungulates, where their simple digestive system cannot process tough plants fibers efficiently as it happens in ruminant animals. The development is not a shortfall but an adaptability issue, where the pig has evolved to address the problem of being fed all types of food. Following the domestication of wild boars during the Neolithic period, the animal needed to place itself in a position it could survive on food sourced from animals as well as plants. McDougall (2012) confirms the claim, where he notes that the evolutionary closeness between human beings and pigs has triggered physiological changes to suit the human-like diet. Such demand has seen pigs adapt to foods like fungi, roots, fruits, snails, earthworms, carrion, eggs, bulbs, insects, as well as leaves (McDougall, 2012). The adaptability goes beyond digestion, as confirmed by the toughening of the snout as well as the use of forefeet in unearthing food plants.

The broad diet has allowed pigs to be reared in all regions around the globe, even in mountainous terrains, snowy areas, and desert environment. The control and management after domestication have also forced pigs to retain their scavenging and rooting behaviors, an attitudinal element that continues to be expressed, 50 million years after the sus domesticus started distancing itself from the other members of Artiodactyl. Beynon (2014) confirms the omnivorous nature of domestic pigs, where he notes that the animal has continued to experience changes in the genetic code, with the primary aspect being refining its strong sense of smell to distinguish food materials. The claims are best captured by way of life of the self-sufficient wild boar, a member of the pig family that does not only take carrion and hunts rabbits, insects, snakes, and rodents, but can also locate easily digestible vegetable matter, nuts, roots, seeds, and truffles. The nature is expected to sustain the gains, where the evolution will continue to refine the physiology of the digestive system of pigs, with the anatomical changes helping the animal not only cope with new foods but also meet their dietary needs.

Common Issues with Feeding Pig in the context of a production system

One of the feeding aspects in the production system has been the introduction of milk formula, where the bottled feed is replacing sow's milk in weaning piglets. Unlike the formula, colostrum and milk are rich in a variety of growth factors required for the development of intestinal morphology. The mammary secretions trigger rapid postnatal intestinal growth, a dramatic change that arises from endocytosis of ingested immunoglobulins (IGF-1), protein synthesis, and mucosal hyperplasia(Lindberg & Ogle, 2001).. The growth factors also cause specific anatomical developments in the gastrointestinal tissues in neonatal pigs. The case is different in formula-fed piglets, where scientific inquiries have confirmed slow weight gain because of the delayed maturation of interstitial mucosa. Nevertheless, the adverse effects of bottle-feeding have been invalidated by the significance of formula in raising underprivileged and supernumerary piglets. The commercial gains of maintaining the whole stock to maturity subdue the morphometric differences contributed by the formula when compared to milk-borne bioactive compounds such as IGF-1 and insulin. The issue has made formula a valuable product in the industrial production of pigs (Lindberg & Ogle, 2001).



References

Beynon, N. (2014). Pigs: a guide to management. Crowood.

Colville, T. P., & Bassert, J. M. (2015). Clinical anatomy and physiology for veterinary technicians. Elsevier Health Sciences.

Cooper, E., & Burton, D. (2014). Agriscience Fundamentals and Applications (p. 510). Boston, Massachusetts: Cengage Learning.

Herren, R. V. (2012). Science of Animal Agriculture. Cengage Learning.

Lindberg, J., & Ogle, B. (2001). Digestive physiology of pigs. Wallingford, Oxon: CABI Pub.

McDougall, L. (2012). Tracking and Reading Sign: A Guide to Mastering the Original Forensic Science. Rowman & Littlefield.

Michael, A. R., & Michael, D. D. (2013). Anatomy and Physiology of Domestic Animals.

Vanhorn, B., & Clark, R. (2011). Veterinary Assisting Fundamentals & Applications (pp. 4000-4001). Clifton Park, NY: Delmar, Cengage Learning