Principles of Feeding Pigs and Feed Resources

Nutrition and feeding management are very important aspects of swine production. Therefore it is extremely important that swine producers have a good understanding of the nutrient requirement of swine during each phase of their life cycle, a knowledge of the feedstuff which can be used in swine feeding, and an appreciation for the final point of feeding management in order to raise swine economically.

Unfortunately, many swine farmers keep them in rather poor conditions and so are not able to make as much profit as they should. Swine are particularly affected by dirty, drafty housing and quickly become sick.

They are also affected by poor feeding. The major groups of essential nutrients for pigs are energy, protein, minerals, vitamins, and water.

Read Also: Proper Ways of Feeding Pigs

Gastro-Intestinal Tract (GIT) and Nutrient Utilization

Swine have the ability to obtain nutrients from a wide variety of feedstuff. Historically the wild swine was omnivorous consuming both vegetative and animal feeds in the early days, domestic pigs were allowed to forage on grass, roots refuse, and whatever else is available.

Swine is a simple stomach animal, so it must rely largely on feeds having readily digestible carbohydrates to meet its energy needs.

The gastrointestinal tract (GIT) is important to the animal because it is made up of a number of organs that are responsible for the utilization of food and nutrient.

Furthermore, some knowledge of its anatomy and function is helpful in evaluating feedstuff and formulation of diet.

Some knowledge of how the GIT digest feed and factors that affect feed utilization is important because losses in digestibility have a marked effect on the efficiency of feed utilization.

In addition, many feed-related factors may alter or change the normal functioning of the GIT. Consequently, some degree of familiarity with its anatomy and function is important for a reasonable understanding of practices and problems in feeding livestock.

The more complex carbohydrate, cellulose hemicellulose found in roughage and other fibrous feeds is broken down by microbial fermentation only. Swine do not have a rumen.

The fibrous component of the diet is not utilized as efficiently as in ruminant animals. Also, simple stomach animals like swine are dependent upon certain essential amino acids present in dietary protein from which they build their own body protein unlike the ruminant animal, swine cannot synthesize the essential amino acids from poor quality protein or from non-protein nitrogen sources.

The relative amounts of the essential amino acids in the protein are extremely important to swine.

The alimentary tract of the pig is designed to digest and absorb concentrated foods. The GIT of simple stomach mammalian specie like the pig include the mouth and associated structures:

  • Mouth
  • Salivary glands
  • esophagus
  • Stomach
  • Small and large intestines
  • Pancreas
  • Liver


Principles of Feeding Pigs and Feed Resources
Image: The digestive tract of pigs

These various organs and other structures are concerned with procuring, chewing, and swallowing food and with the digestion and absorption of nutrients as well as with some excretory functions.

Food taken in the mouth is ground into a pulp by mastication. At the same time, it is moistened and mixed with saliva. Saliva contains the enzyme ptyalin which initiates the breakdown of starch into simpler carbohydrates.

The food then passes on into the stomach, which provides an acid environment due to the presence of hydrochloric acid. The gastric juice contains the enzyme pepsin which begins the breakdown of protein.

The small intestine is the major site where food absorption occurs, and digestive juice from the pancreas, liver, and small intestine completes the process of digestion. Digestion has been defined simply as the preparation of food for absorption.

It may include mechanical forces such as chewing or mastication and muscular contraction of the GIT. The overall function of the various digestive processes is to reduce food particles to a size of solubility that will allow for absorption.

Read Also: Pig Housing Design and Requirements

For instance, starch is hydrolyzed to maltose by amylase from the pancreatic juice. Maltose and other disaccharides sugars are broken down by specific enzymes in the intestinal juice, e.g. Maltase, lactase, and sucrose into monosaccharides such as glucose and fructose these are then absorbed through the gut wall.

Trypsin in the pancreatic juice acts on protein to produce polypeptides, which are then broken down to amino acids by various peptidases in the intestinal juice and subsequently absorbed.

Bile which is secreted by the liver serves to emulsify fats into smaller globules, which are then broken down by enzyme lipase into fatty acids and glycerol ready for absorption. Lipase is present in both the pancreatic and intestinal juices.

Absorption includes various processes that allow small molecules of digestible food to pass through the membrane of the GIT into the blood or lymph systems.

The shape of the stomach of different animal species varies thus the relative size within species as well as among species. In swine, the stomach is relatively large with a capacity in the adult on the order of 6-8 liters.

The weight of the stomach and its content is about 4% of body weight as compared to 1% in humans.

Most of the stomach is lined with mucosal cells which produce mucus that serves to protect the stomach lining from gastric secretions. In the central part of the stomach, there are gastric glands that produce a mixed secretion of enzymes and mucus.

These gastric juices are effective in initiating digestion in the stomach. In swine, the small intestine is relatively long 15-20meters. The first portion of secretion is the duodenum which is the side for the production of various digestive juices.

Other juices enter the duodenum from the bile duct, while Other juices are derived from the liver and the pancreas. The small intestine is lined with small finger-like projections the villi, which serve to increase surface area for absorption.

The large intestine is made up of the caecum, colon, and rectum. The relative length and diameter differ considerably in different species of animal.

Pigs are omnivores and will consume a wide range of foods from both plant and animal sources. The natural inclination of the pig is to eat on a ‘little and often basis, and this is likely to maximize both total food intake and the efficiency of food utilization.

Read Also: Recommended Feed Formula for Piglets (Baby Pigs)

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Benadine Nonye

An Agric. Consultant & a Writer (With over 12 years of professional experience in the agricultural industry) - National Diploma in Agricultural Technology - Bachelor's Degree in Agricultural Science - Master's Degree in Science Education... Visit My Websites On: - It's All About Agriculture, The Way Forward! - The Most Reliable Global Agricultural Forum! - The Most Reliable Nigeria's Agricultural Job Board! - For Everything Premium Agriculture! - For Proper Waste Management and Recycling Practices. Join Me On: Twitter: @benadinenonye - Instagram: benadinenonye - LinkedIn: benadinenonye - YouTube: Agric4ProfitsTV - Pinterest: BenadineNonye4u - Facebook: BenadineNonye

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