Introduction

Vitamins are essential organic compounds required in minute amounts in the diets of humans and animals for normal metabolic function. Vitamins are involved in over 30 metabolic reactions at the cellular level involving carbohydrate, fat, and protein metabolism. All complete feeds made for livestock in confinement are fortified with crystalline or synthetic sources of vitamins. Crystalline vitamins supplement the natural vitamin content of feed ingredients (mainly grains) that are known to be deficient in diet formulations. However, not all the vitamins required metabolically by livestock are provided in a vitamin supplement or premix because: 1) The feed ingredients may contain adequate bioavailable amounts of one or more vitamins or their precursors; 2) the microflora in the digestive tract of adult animals may synthesize adequate amounts under normal conditions; 3) dietary antibiotics may alter the intestinal microflora and their synthesis of vitamins; and 4) the vitamin is synthesized by body tissues. In the latter case, Vitamin C (ascorbic acid) is synthesized in body tissues of most animals, but not in humans (primates) or guinea pigs. The chemistry and commercial synthesis of all the vitamins required for supplementation in human and animal nutrition is well known.

Manufacturers of crystalline vitamins provide guaranteed amounts of vitamins in concentrated supplements known as premixes. The fat-soluble vitamins A, D, E, and K require dietary fat for their absorption from the small intestine. When vitamins A and D (not vitamins E and K) are consumed in great excess, they accumulate in body tissues and eventually produce toxicity. The B vitamins the water-soluble vitamins are not stored in body tissues and need to be provided continuously to maximize metabolic efficiency and prevent vitamin deficiencies.

Gaining Weight 101

Gaining Weight 101

Find out why long exhausting workouts may do more harm than good. Most of the body-building workout and diet regimens out there are designed for the guys that gain muscle and fat easily. They focus on eating less and working out more in order to cut the excess fat from their bodies while adding needed muscle tone.

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