Bioenergetics and nitrogen balance of the European eel ( Anguilla anguilla ) fed at high and low ration levels
European eel (Anguilla anguilla) were fed either high or low ration levels (1.33 and 0.48% body weight·day 1 ). Eight periods of continuous 24-h respirometry in flow-through conditions were conducted over 70 days to simultaneously examine nitrogen and energy budgets without resorting to the calculat...
| Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1998
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f98-119 http://www.nrcresearchpress.com/doi/pdf/10.1139/f98-119 |
| Summary: | European eel (Anguilla anguilla) were fed either high or low ration levels (1.33 and 0.48% body weight·day 1 ). Eight periods of continuous 24-h respirometry in flow-through conditions were conducted over 70 days to simultaneously examine nitrogen and energy budgets without resorting to the calculation of parameters by difference. Food and oxygen consumption; ammonia, urea, and nitrate-nitrite excretion; and growth production were measured. Nitrogen budgets successfully accounted for 89.6-101.2% of the consumed nitrogen. Energy budgets accounted for 53.4-92.3% of the consumed energy. From the ammonia quotients (AQ), 54.4-57.7% of the available protein was oxidized at high ration, and 59.7-133.5%, at low ration level. To satisfy maintenance requirements, 0.28 mg N·g -1 ·day -1 was required. At 25°C eels were calculated to have a rate of standard metabolism of 83.3 J·g 1 ·day -1 , which is comparable with the range published for other species at this temperature. These data suggest that eels do not have a particularly low metabolic rate, as is commonly assumed in the eel rearing industry, and that the relatively inactive lifestyle associated with the eel masks a metabolic rate in common with other, more active, fish. |
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