Effect of colostomy on the occurrence of dietary [15N]urea in intestinal contents, blood, urine and tissues in chickens fed a low protein diet plus urea.
1. The occurrence of 15N was examined in excreta for 10 h, and in intestinal contents, blood and tissues at 10 h after [15N]urea was fed to conventional and colostomised cockerels. 2. Total-15N excretion and 15N-balance in control chickens were 18.88 and 44.79 mg/kg body weight/10 h), respectively. The former was increased and the latter was decreased by colostomy by 10.75 mg (P < 0.01). 3. Amounts of [15N]urea, [15N]ammonia and [15N]uric acid excreted by control birds were 13.78, 3.90 and 0.18 mg/kg body weight/10 h or 0.73, 0.21 and 0.01 of the total-15N excreted respectively. 4. The [15N]urea, [15N]uric acid and total-15N excreted were all increased after colostomy but [15N]ammonia was decreased (uric acid P < 0.05, others P < 0.01). The increase in total-15N was mostly accounted for by [15N]urea. 5. Colostomy resulted in significantly less total-15N in the contents of the whole intestine (P < 0.01), less total-15N, [15N]ammonia and [15N]urea in the contents of the colo-rectum (P < 0.01) and less total-15N and [15N]urea in the contents of the upper intestine (P < 0.05); it did not affect any in caecal contents. 6. [15N]Urea in blood, liver and kidney (blood P < 0.01, others P < 0.05), and [15N]glutamine amide (P < 0.05) and [15N]uric acid (P < 0.01) in blood were significantly decreased after colostomy. 7. The results support the hypothesis that most of the dietary urea is utilised as the result of a back-flow of ureteral urea into the caeca where it is rapidly converted into ammonia which is then metabolised to other compounds.
Karasawa
Y
Y
Laboratory of Animal Nutrition and Feed Science, Faculty of Agriculture, Shinshu University, Nagano-Ken, Japan.
Maeda
M
M
D000821:Animal Feed; D000818:Animals; D001682:Biological Availability; D002432:Cecum / Q000378:metabolism*; D002645:Chickens / Q000378:metabolism*; D003106:Colon / Q000378:metabolism*; D003125:Colostomy / Q000662:veterinary; D018753:Diet, Protein-Restricted / Q000662:veterinary*; D008297:Male; D014508:Urea / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine
D014508:Urea