Nitrogen absorption and endogenous nitrogen along the intestinal tract of chicks.

Six groups of 15 chicks each were fed ad libitum experimental diets that contained between 0.4 and 35 g nitrogen/kg, from 10 to 16 d of age. Soybean meal was the only source of protein, and the marker was magnesium ferrite.

Nutritional value of feather-meal protein for chicks.

Ileal absorption of nitrogen was determined for feather meal (FM) samples, using magnesium ferrite as a marker. Diets containing 15% FM were balanced by linear programming, using two nitrogen absorption values for FM: 55%, as found, or 85%, an average value for standard feeds. When nitrogen absorption of FM was calculated as 55%, the growth of chicks from one to three weeks of age was similar to that of the control chicks.