Utilization of Dietary Urea in Rainbow Trout
作者:
S.J. Kaushik,
K.R. Dabrowski,
H. Dabrowska,
E. Olah,
P. Luquet,
期刊:
Annals of Nutrition and Metabolism
(Karger Available online 1983)
卷期:
Volume 27,
issue 2
页码: 94-106
ISSN:0250-6807
年代: 1983
DOI:10.1159/000176628
出版商: S. Karger AG
关键词: Urea supplementation;Urea utilization;Digestibility;Excretion;Ammoniemia;Uremia;Rainbow trout
数据来源: Karger
摘要:
Experiments were conducted to examine the potential utilization of dietary urea by rainbow trout. A control diet and two diets supplemented with 1 and 3 % of urea were fed to fish. Postprandial levels of urea and ammonia in blood plasma, and postprandial excretion of these metabolites were followed during 24 h. Apparent digestibility of urea in rainbow trout was very high ( > 98%). Maximum values of urea levels in plasma were reached 6 h (32.3 ± 10.2 µg/ml) after a meal in the control fish and respectively 6 h (83.4 ± 18.4 µg/ml) and 8 h (250.3 ± 96.1 µg/ml) after a meal in trout fed 1 and 3% urea diets. Peaks of urea excretion rates appeared 7–9 h after meal, coinciding with the highest circulating urea concentration. Total daily urea excretion amounted to 5.53, 10.43 and 33.80 mg urea N/100 mg N intake in trout fed the control, 1 and 3 % urea diets, respectively. It is concluded that the dietary urea is readily absorbed in the digestive tract of trout but is totally excreted thus leading to no beneficial effect on nitrogen balance. This excretion of urea also takes place passively without any increase in energy
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