Incorporation of intraportal ammonia-N into blood and tissue nitrogenous compounds in chickens fed low and high protein diets

Maeda

1994

1. A study was carried out to investigate whether the back-flow of urine into the caeca benefits the nitrogen economy of adult cockerels fed on a diet containing 100 g protein/kg and when dietary urea is absorbed, excreted into urine and utilised. 2. No significant effects of colostomy on nitrogen utilisation were observed in chickens fed on 100 g/kg protein diet, whereas colostomy was highly effective in decreasing it in chickens on a diet containing 50 g protein/kg plus urea (P < 0.05). 3. Nitrogen utilisation in conventional birds was significantly less when a diet of moderate protein content was fed than when a low protein diet plus urea was fed, but the opposite effect was seen with colostomised birds (P < 0.05). 4. Colostomy increased urea excretion (nitrogen/kg body weight/day) from 4 to 9 mg in chickens fed on the moderate protein diet, but greatly, from 45 to 182 mg, in those fed on the low protein diet plus urea (P < 0.05). 5. Blood urea concentration increased by about 20 mg per 100 ml in 3 h, a value which was maintained up to 6 h but which returned to the prefeeding concentration at 24 h; both control and colostomised chickens on the low protein diet plus urea responded similarly. 6. After feeding urea, half the daily excretion of urea was observed to occur within 6 and 9 h, respectively, in control and colostomised chickens.(ABSTRACT TRUNCATED AT 250 WORDS)

Section: Discussionmentioning

confidence: 68%

Role of caeca in the nitrogen nutrition of the chicken fed on a moderate protein diet or a low rotein diet plus urea

Maeda

1994

“…Further details of the procedures followed for 15 N-determinations of total nitrogen in excreta and intestinal contents, of uric acid in blood, excreta and tissues, and of ammonia in blood, excreta, tissues and intestinal contents have been reported by Karasawa (1986) and Nakata (1986, 1989). [ 15 N]Glutamine amide in blood and tissues and [ 15 N]urea in excreta, intestinal contents, blood and tissues were measured as described by Karasawa and Koh (1987).…”

Section: Methodsmentioning

confidence: 99%

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

Maeda

1995

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.

“…The methods of Karasawa (1986) and Karasawa and Nakata (1989) were used to determine 15 N enrichments of total nitrogen in urine, caecal contents, protein and non-protein N of blood and tissues, uric acid in urine and tissues, and ammonia in urine, caecal contents and blood. Glutamine amide-15 N in blood and tissues and urea-15 N in urine, blood and tissues were measured as described by Karasawa and Koh (1987).…”

Section: Methodsmentioning

confidence: 99%

Occurrence of intraportally‐infused urea‐¹⁵N in the urine of domestic fowl

Koji²,

Maeda³

1992

1. Measurements were made in situ to determine the occurrence of intraportally infused urea-15N in ureteral urine of the fowl. 2. Of the total amount of infused urea-15N, 15% was excreted intact into the urine (90% of urinary total 15N) whereas 9% remained unchanged in the blood (78% of blood non-protein-15N). 3. The proportions of non-protein-15N in the blood, liver and kidney were 12, 3 and 1%, respectively of the infused 15N. Protein-15N was 3% of that infused in blood and much less in liver and kidney. 4. About 1% of the infused 15N was observed in the urinary uric acid, and 3% of the infused 15N in non-protein N, other than urea, ammonia and glutamine amide N, of blood and liver. 5. No appreciable amounts of 15N were present in ammonia and glutamine amide N of blood, liver or kidney and in uric acid of liver or kidney. 6. The caecal contents contained about 1% of the infused 15N with 15% of this as ammonia-15N. 7. It is concluded that intraportal urea is mostly excreted unchanged into ureteral urine of the fowl.