Effects of dietary protein/energy ratio, ration size, dietary energy source and water temperature on nitrogen excretion in rainbow trout

1995 ◽  
Vol 31 (10) ◽  
Keyword(s):  
Energy Source ◽  
Rainbow Trout ◽  
Water Temperature ◽  
Dietary Protein ◽  
Nitrogen Excretion ◽  
Energy Ratio ◽  
Dietary Energy ◽  
Protein Energy ◽  
Ration Size

Effects of dietary protein/energy ratio, ration size, dietary energy source and water temperature on nitrogen excretion in rainbow trout

1995 ◽  
Vol 31 (10) ◽  
pp. 185-194 ◽  
Author(s):  
F. Médale ◽  
C. Brauge ◽  
F. Vallée ◽  
S. J. Kaushik
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Dietary Protein ◽  
Protein Level ◽  
Dry Matter ◽  
Ammonia Excretion ◽  
Nitrogen Excretion ◽  
Digestible Energy ◽  
Protein Energy ◽  
Ration Size

Postprandial nitrogen excretion was measured on groups of rainbow trout of mean body weight (MBW) 35g, fed, from maintenance to near satiation, diets containing graded levels of digestible energy (14 to 20 kJ/g dry matter) with digestible protein (DP)/digestible energy (DE) ratios of 18 and 23 mg/kJ at each protein level (DP: 32.5 or 37% dry matter). Irrespective of the diet and the ration size, urea-N excretion amounted to 15-16% of ammonia-N excretion. The higher the dietary DP/DE ratio, the greater was the amount of ammonia excreted. At high ration levels (1.5% and 2% of MBW/d), N excretion was 39-40% of digestible N intake for diets with a DP/DE ratio of 18 mg/kJ and 44% of digestible N intake for diets with a DP/DE ratio of 23 mg/kJ irrespective of the dietary protein level. At lower ration levels, N excretion as percent of N intake was higher than at higher feeding levels. Another experiment was performed to compare the effect of dietary lipid and digestible carbohydrate on ammonia excretion in rainbow trout reared at two water temperatures (8°C and 18°C). Neither water temperature nor dietary sources of non-protein energy had any significant effect on N excretion expressed as proportion of digestible N intake.

Maximum Tolerable Level, Digestion, and Metabolism of D-Glucose (Cerelose) in Rainbow Trout (Salmo gairdneri) Reared on a Practical Trout Diet

1982 ◽  
Vol 39 (9) ◽  
pp. 1229-1234 ◽  
Author(s):  
J. W. Hilton ◽  
J. L. Atkinson ◽  
S. J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Glucose Level ◽  
Energy Content ◽  
Liver Glycogen ◽  
Salmo Gairdneri ◽  
Dietary Energy ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Increased Activity ◽  
Tolerable Level

The maximum tolerable dietary level, digestion, and metabolism of D-glucose (cerelose) were investigated in rainbow trout (Salmo gairdneri) reared on practical diets containing optimum protein and lipid levels at two different water temperatures for 12 wk. Liver glycogen levels (LG) and liver:body weight ratios (LB) initially increased with increasing dietary glucose, but leveled off above 10–15% glucose. The plateauing of LB and LG was consistent with the plateauing of liver glucose-6-phosphate dehydrogenase activity (G6PD) and probably overall hexose monophosphate shunt (HMS) activity at high dietary levels of glucose. This indicates that there may be an optimum ratio of digestible carbohydrate to lipid in salmonid diets. LG and LB tended to be higher in trout reared upon the same dietary glucose level in fish reared at 11 °C as compared with those at 15 °C. This may have been caused by increased activity of the HMS as indicated by increased activity of liver G6PD in fish acclimated to 11 °C as compared to trout reared at 15 °C on the same dietary glucose level (when assayed at 15 °C). The digestion coefficient of glucose was uniformly high (96–99%) and not affected by either dietary glucose level (up to 25% of the diet) or water temperature (11 or 15 °C). The maximum tolerable level of glucose in salmonid diets appears to be dependent upon the protein, lipid, and overall energy content of the diet.Key words: trout, glucose digestion, glucose metabolism, maximum tolerable levels, water temperature, dietary energy

The effect of dietary energy source on diet digestibility and growth performance of rainbow trout

1999 ◽  
Vol 1999 ◽  
pp. 222-222
Author(s):  
R.N. Weatherup ◽  
K.J. McCracken
Keyword(s):  
Heat Treatment ◽  
Energy Source ◽  
Body Composition ◽  
Rainbow Trout ◽  
Fish Oil ◽  
Growth Performance ◽  
Fat Deposition ◽  
Dietary Energy ◽  
Raw Starch ◽  
Carnivorous Fish

There is confusion in the literature as to the effects of carbohydrates in the diet of fishes. Warmwater, herbivorous fishes can digest more complex carbohydrates (Shiau and Chuang, 1995) while coldwater, carnivorous fish may digest glucose better. However high levels of dietary glucose may increase fat deposition in the viscera (Bergot, 1979). Furthermore, Kaushik and de Oliva-Teles (1985) reported that heat treatment of raw starch in diets for rainbow trout improved its utilisation. This study was conducted to determine the digestibility of diets containing raw wheat, extruded wheat, glucose and fish oil. The effects of these diets on growth performance and body composition of trout were also determined.

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