Friday 22 February 2013

Pig nutrition: minerals and vitamins

Minerals are inorganic elements, which are divided into trace elements (or microminerals) and macrominerals depending on how much of each is present in the animal body. Trace elements are those elements, which the animal needs less than 0,01 % of the dry matter weight of it's tissues. Minerals are needed for three tasks ( (T) after the element name denotes it's a trace element):
  • Building tissues
    • Calcium
    • Phosphorus
    • Magnesium
    • Silicon (T)
    •  Fluorine (T)
    • Sulphur
  • Regulating osmotic pressure and permeability of cell membranes
    • Sodium
    • Potassium
    • Chlorine
    • Calcium
    • Magnesium
  • Catalyzing enzymatic and hormonal regulation
    • Iron (T)
    • Cobalt (T)
    • Zinc (T)
    • Manganese (T)
    • Molybden (T)
    • Selenium (T)
Vitamins are biologically active, organic compounds, which are necessary for normal bodily functions, and cannot be replaced with any other compound. Many vitamins are a part of an enzyme. Vitamins have five basic functions: antioxidant activity, proton/electron recipient, hormonal activity, coenzymatic activity and participation in genetic transcription.

Pigs need to get most of their vitamins from the feed. The vitamin content of feeds decrease during storage and processing,  so especially highly productive animals need vitamin additions. Age, health, stress, diet composition, gender and physiological state affect the need for vitamins. Vitamins of the K- and B-groups are formed in the color by microbes, but absorbancy may be weak. The minimum dose is where no symptoms of deficiency are apparent. The optimum need is the amount of vitamins needed to secure as high a production as possible, health, resistance against illnesses and adequate vitamin reserves.Exceeding the optimum need is costly, since the excess is secreted out from the body. Vitamins may also have toxic effects if the dosage is greatly exceeded for a long period of time.

Pigs are often raised indoors, so they cannot synthetize D vitamin from sunlight at all. Normally pigs could get K and B vitamins from feces, but if there's grating on the floor, this too becomes impossible. The most often needed vitamins are already added to commercial pig feeds and concetrates: A, D and E vitamins, niacin (B3), pantothenic acid (B5), riboflavin (B2) and B12.  Basic vitamin need stays the same for the entire life of a meat pig, but sows and and boars need more vitamin A and D than growing pigs and piglets. Sows and boars also need added choline, folic acid and K-vitamin.

The details of the different vitamins are discussed in another post about vitamins. Some vitamins have specific effects on  pigs:
  • Vitamin E: increases litter size, prevents milk fever, increases immunity on sows and piglets
  • Choline: increases fertility of sows and the amount of piglets born alive. Pigs can synthetize choline from methionine.
  • Vitamin K: additions are needed for pregnant sows, so the vitamin can permeate the placenta and also absorb into the colostrum
  • Biotine: may improve claw health

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