Untersuchungen zum N-Stoffwechsel des Broilers mit15N-markiertem Weizen

Abstract

17 broilers received a wheat-soya bean meal-pea nut ration containing an excess of 15N atom% (6.54%). The birds were slaughtered 3, 6, 12, 36, 60 and 108 hours after the last 15N'-intake. Up to 12 hrs after slaughtering the contents of the crop and the stomachs were found to contain a higher excess of 15N atom% than the food. The contents of the small intestine at that time contained only 1/4 of the 15N concentration present in the crop and the stomachs (2.7%). Later on the excess of 15N atom% decreased to 1.7%, 1.4% and 0.8% and was 4 times as high as that found in the crop and the stomach. Higher 15N' concentrations, compared with those in the small intestine, were found in the contents of the caecum, the colon, and the rectum, for a period of up to 12 hrs after administration of the last portion of labelled food. The 15N' concentrations in the crop and the stomachs are due to a more prolonged storage of wheat relative to that of the extracted meals. The interrelationship between the contents of the small intestine and the contents of the higher sections of the gastro-intestinal tract suggests that a secretion of N-containing substances takes place, although it was not possible to determine these substances quantitatively. Values for the excess of 15N atom% in the crop and oesophagus and in the muscular stomach were found to be in close correspondence both with regard to their level and time pattern. The decline in the glandular stomach was more rapid than in the muscular stomach. A very close correlation (r=0.99) was found between the 15N atom% in the contents of the intestine and in the intestinal wall. The N content of the small intestine (expressed as mg) was significantly higher after 3 hrs and 6 hrs of fasting than after a fasting period of 12 hours. Theoretical aspects of the involvement of the intestine in the process of metabolism are discussed in some detail.