Gordon King, Animal Science, University of Guelph, Canada
The aim of any feeding program should be to satisfy nutrient requirement at a reasonable cost. This infers provision of a diet balanced for optimum but not usually maximum production. Optimum involves a least cost concept with maintenance of health, proper rate of gain and finish. Each lot of pigs contains individuals with varying requirements for individual nutrients. It is not practical to include sufficient amounts of every nutrient to meet the needs of everyone. If this were done, most of the population would receive excess which, in addition to being costly, could result in less desirable carcasses and even in toxicity. A general guide for growing-finishing pigs might be to provide rations that result in maximum performance for about 85% of animals in a healthy, adequately housed group possessing a genotype for high production and maintained within their comfort zone.
Some of the points to consider are:
Don't forget water
Barley - main energy source for pigs in western Canada and much of Europe.
Oats - excellent for mature animals, particularly if dehulled. Oats are not as good for younger pigs but can provide 20 - 30 % of the total energy source.
Wheat - very good energy source if price is right.
Canola (Oilseed Rape). The meal remaining after oil extraction from Tower or Candle varieties, the common types grown in Canada. Canola meal is an excellent protein source for pigs. The earlier varieties of Rape, still grown in some parts of Europe, contain toxic factors (glycosinolates) that make this meal unsatisfactory for pig diets.
Minerals and Vitamins
The specific needs for minerals and vitamins vary considerably with the age and production stage
of particular animals. Most producers incorporate the appropriate vitamin-mineral premixed into
all diets.
Preservatives. antioxidants, gelatin coatings for vitamins, organic acids,and similar compounds are sometimes included to prevent or reduce deterioration during storage
Flavouring & Colouring Agents. Sweetening and flavourings are common in early wean diets to give milk-like taste. Colours are sometimes used to distinguish diets, particularly if feed is medicated.
Texturing agents may be added to promote pelleting. Eg. molasses to assist passage through screens; beet pulp to improve texture.
Antibiotics - to inhibit or kill bacteria.
Many used, often not pure pharmaceutical grade but rather the dried fermentation product
containing antibiotic residues plus mycelium of the producing fungus.
May prevent degradation of nutrients by bacteria during storage. Producers should do all they can
to minimize and eventually eliminate the routine need for these.
Antifungal & antiprotozoal compounds. These are mainly anthelmintics.
Other Antimicrobials (those not derived from fungi)
CuSo4 An inexpensive additive that may reduce microbial action during storage. Aarsenicals are
also used or this.
Enzymes
The incorporation of various enzymes into pig diets is a relatively new concept. However, if their
production costs can be reduced through biotechnological synthesis or some other practical
procedure, the practice might become universal. Some prospects are: proteases to make protein
more available; b-glucanase to break down complex cereal starches to glucose; cellulase to digest
plant cell walls; and phytases to liberate tightly bound phosphates. Any of these enzymes could
liberate specific nutrients from plant materials so these are available to the animals in greater
quantities.
Probiotics
Usually dried mixtures of lactobacillus and other microflora which, when added to diet, multiply
in gut to displace less desirable and possibly pathogenic species. Most are trade secrets.
Gut Acidifiers.
Citric and fumaric acids maintain acidity of duodenum without altering body's acid:base balance.
Distressed pigs, such as those at weaning, may have impaired gut function so stomach secretes
less acid to control bacterial flora in the intestine. Acidifiers compensate for this.
Immune Stimulants.
Killed or attenuated microorganisms, often given to sows prior to parturition to promote passive
immunity in piglets. Some may also give direct to piglets to promote active immunity.
Chelating Agents.
Claim is that trace elements bound to chelating agents are protected from binding to other
components that may prevent absorption, and then released for absorption at critical part of
intestine.
Emulsifying Agents
Necessary if fat included in diet.
Metabolic Modifiers
Compounds such as beta-agonists or recombinant porcine somatotrophin alter metabolism,
promoting deposition of more muscle. Certainly the pork chops from pigs treated with rpST have
less fat and, in the opinion of most marketing specialists, more consumer appeal. The use of such
pharmaceuticals is certainly a grey area at present but some of the presently available or even
new compounds might evolve into practical methods to modify growth and carcass composition.
The Extension Swine Husbandry Staff at North Carolina State University produce a number of Nutrition Related Topics, including a Swine Nutrition Guide, that provide an informative coverage of nutrition and feeding topics.
Some additional information on nutritional requirements and feeding practices are available in the Swine Care Handbook prepared by the National Pork Producers Council.
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