[Determination of the apparent digestibility of crude proteins in chickens using the alpha-NH2-N method]

Based on a comparison between colostomy, the alpha-NH2-N method introduced by PAHLE et al. (1983, 1985), the HARTFIEL (1963) and the EKMAN (1948) methods of the separation of faecal N and urine N in the determination of the apparent digestibility of crude protein in chickens, extensive studies were carried out with mixed excrement from colostomy experiments and excrement samples from intact animals from digestibility experiments with different feedstuffs. In case of the application of the methods by HARTFIEL and EKMAN there were partly big deviations in the measured results. A modification of the alpha-NH2-N method applied by us showed results which largely agreed with the results of colostomy and the method developed by PAHLE.