15N-lysine studies in colostomized hens. 2

Over a period of 4 days colostomized hens were given 15N-lysine, and the development of 15N excretion both in the TCA-soluble and the TCA-precipitable fraction of the feces was measured over 8 days. In both fractions the total, lysine, histidine and arginine N and 15N excess (15N') was determined. The apparent digestibility of 14N was 81.2 % +- 1.1 % and of 15N' 93.2 % +- 0.7 % on the average. Labelled N is already excreted in feces 3 hours after application. The TCA-precipitable N is less strongly labelled than the TCA-soluble N. During the application of 15N' the labelling in fecal lysine is nearly one power of ten higher than in total N. The atom-% 15N' of the lysine could also be distinctly detected in arginine and histidine. The quotas of the total 15N' in feces were 3.5 % for arginine-15N' and 0.8 % for histidine 15N'. 15N' was traceable mainly in the soluble fraction. (author)