Factors affecting vitamin utilization
Raw soybean contains enzyme lipoxygenase which can be destroyed by heating for 5 min with steam at atmospheric pressure. Lipoxygenase catalyses oxidation of carotene, the precursor of vitamin A. Diets with raw kidney beans produces muscular dystrophy in chicks and lambs by reducing plasma vitamin-E. Autoclaving destroys this factor. Eating sweet clover causes fatal hemorrhagic condition in cattle, known as ‘sweet clover disease’. Dicoumarol (anti-vitamin K) present in sweet clover is responsible for this condition by reducing prothrombin levels in blood thereby affecting blood clotting.
Rachitogenic activity (antivitamin D) of isolated soy protein (unheated) has been found with chicks and pigs. Autoclaving eliminates the rachitogenic activity. Nutritive value of linseed meal for chicks can considerably improve after water treatment and autoclaving. Niacitin, an antagonist of niacin is found in maize, wheat bran etc. which causes perosis and growth depression.Many of the NCFR contain substances that are deleterious to animal health. If these feedstuffs are used without treatment death may occur in extreme cases. Fortunately, methods are now available to detoxify most of these compounds.The chemical compound ‘tannins’ are wide spread in feedstuffs such as salseed meal and tamarind seed hulls but the ruminants can tolerate a much higher concentration of tannins than the poultry. These tannins can inhibit the activity of rumen microbes and depress the digestion of protein and fiber. On the other hand, tannins have been used to protect proteins from breakdown in the rumen.