title: [Utilization of 15N marked urea by the laying hen. 2. Incorporation and metabolism of 15N for the synthesis of egg protein].
abstract: In an N-metabolism experiment 3 colostomized laying hybrids received 2870 mg 15N-excess (15N') per animal in 6 days in the form of urea with their conventional feed rations. During the 8-day experiment the 21 eggs laid were separated into eggshell, white of egg and yolk. Weight, N-content and 15N' were determined of the individual fractions of the eggs. On an average of the 21 eggs 4.6% of the heavy nitrogen was in the egg-shells, 50% in the white of egg and 45.5% in the yolk. 2.8%, 4.5% and 5.5% (hens 1...3) of the 15N' consumed were detected in the eggs. The maximum 15N'-output in the white of egg was reached on the 6th day, whereas 15N'-output in the yolk showed a nearly linear increase in the time of the experiment. The results show that labelled nitrogen from urea is incorporated into the egg to a lower degree than after the feeding of 15N-labelled proteins and that the development of its incorporation into the white of egg and the yolk differ from that after the feeding of 15N-labelled native proteins.
mesh_terms: D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004527:Egg Proteins / Q000378:metabolism*; D004528:Egg Shell / Q000032:analysis; D004529:Egg White / Q000032:analysis; D004530:Egg Yolk / Q000032:analysis; D005260:Female; D009584:Nitrogen / Q000378:metabolism; D014508:Urea / Q000378:metabolism*
chemical_list: D004527:Egg Proteins; D014508:Urea; D009584:Nitrogen
vernacular_title: Zur Verwertung von 15N-markiertem Harnstoff bei der Legehenne. 2. Mitteilung. Inkorporation und Stoffwechsel des 15N für die Eiproteinsynthese.