Bielorai, R., Division of Animal Nutrition, Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel
Harduf, Z., Division of Animal Nutrition, Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel
Iosif, B., Division of Animal Nutrition, Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel
Alumot, E., Division of Animal Nutrition, Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel

1. The apparent absorption values of individual amino acids from two samples of feather meal (FM) were determined in the lower ileum of chicks fed.on diets containing magnesium ferrite as a marker. 2. The average absorption values for FM amino acids were low, approximately 0.50, as compared with approximately 0.85 for soya bean, used as a control. Values for individual amino acids from FM differed distinctly, ranging from 0.20 to 0.70. Low values were obtained for aspartic acid, histidine, lysine, glutamic acid and cystine. 3. An indication of the low absorption of the previously-mentioned amino acids was obtained by analysing the amino acid composition of the FM residues undigested by pepsin or pancreatin. 4. The reasons for testing the apparent rather than the true absorption are discussed. © 1983, The Nutrition Society. All rights reserved.