Crude Fiber as a Tracer in Poultry Nutrition Studies

An effective feed tracer or marker must be convenient to apply and be easily and quantitatively measured. It must be inert, not cause intestinal disturbances or illness, and not markedly change the appearance of the feed so as to cause changes in feeding habits or to excite the birds. Excitement can alter the rate of food passage through birds (Henry et al., 1933) (Tuckey et al., 1958). Dye markers such as gentian violet and methylene blue have caused enteritis and constipation in chickens (Kaup and Ivey, 1923). Ferric oxide and powdered charcoal markers caused diarrhea when used in workable quantities (Hillerman et al., 1953). One marker which did not require force feeding and did not affect the bird was chromic oxide (Jensen et al., 1962). However, detection of this marker in feed and feces requires spectrophotometric equipment. A most recent and novel suggestion is to use as a marker the…