Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 10

Over a period of 4 days 12 colostomized laying hens daily received 36 g coarse wheat meal containing 14.37 atom-% 15N excess (15N') together with a conventional ration. After the homogenisation of each oviduct N and 15N' were determined. After the precipitation with TCA the 15N' of the amino acids was analysed in both the precipitate and the supernatant. In addition, the free amino acids and the peptides were determined in the TCA soluble fraction. The atom-% 15N' in the total N and in the non-basic amino acid N showed a parallel decrease; it diminshed from 1.75 atom-% 15N' to 0.64. Of the three basic amino acids, lysine shows the lowest labelling at all four measuring points. The quotas of non-basic amino acid 14N and 15N' in the total 14N and 15N' of the oviduct are the same and amount to 53%. In contrast to this, the quota of the 14N of the basic amino acids in the total 14N of the oviduct only amounts to 21.6% and that of 15N' only to 15.4%. The average atom-% 15N' of the free amino acids 12 h after the last 15N application is 1.54 and is considerably above that of the peptides with 1.15 atom-% 15N'. 36 h after the last 15N application the ascertained value of 1.25 is identical in both fractions. The labelling of the free amino acids decreases more quickly than that of the peptides the more time has passed after the last 15N application. (author)