Relationships between dietary ascorbic acid status and deficiency, weight gain and brain neurotransmitter levels in juvenile rainbow trout,Salmo gairdneri

1989 ◽  
Vol 6 (6) ◽  
pp. 353-365 ◽  
Author(s):  
W. L. Johnston ◽  
E. MacDonald ◽  
J. W. Hilton
1977 ◽  
Vol 34 (11) ◽  
pp. 2203-2207 ◽  
Author(s):  
J. W. Hilton ◽  
C. Y. Cho ◽  
S. J. Slinger

Due to the instability of supplemental ascorbic acid in practical trout diets and the increased metabolism of this vitamin in trout ingesting enviromental toxicants, a method of assessing the adequacy of dietary ascorbic acid and the ascorbic acid status of the trout is required. Two groups of trout grown on ascorbic acid deficient diets produced deficiency symptoms within 16–20 wk. Liver ascorbic acid concentrations in the two groups declined to levels below 20 μg/g when deficiency symptoms appeared. Groups of trout grown on diets containing supplemental ascorbic acid to provide near or in excess of the National Research Council–National Academy of Science requirement for this vitamin after processing showed substantially higher liver ascorbic acid concentrations than the deficient fish. This indicates that the liver ascorbic acid concentration can be used as an index of the ascorbic acid status of the trout and that levels 20 μg/g or lower are marginal and immediate supplementation is required. Key words: ascorbic acid, rainbow trout, nutritional requirements


1977 ◽  
Vol 34 (6) ◽  
pp. 869-878 ◽  
Author(s):  
D. M. Whittle ◽  
K. W. Flood

Static and continuous-flow bioassays utilizing juvenile rainbow trout (Salmo gairdneri) were conducted on a northern Ontario bleached kraft mill effluent to assess the range of acute toxicity and related sublethal effects. The acute toxicity of the total mill effluent, as determined by static bioassay procedures, ranged from a 96-h LC50 value of 14–49.0% vol/vol. The results of these bioassays depended on testing methodology and effluent treatment systems employed by the mill when samples were collected. Continuous-flow bioassays conducted on the effluent Produced 96-h LC50 values of 21.8 and 24.8% vol/vol. Growth rate of juvenile rainbow trout (1–2 g) held under continuous-flow conditions for 18 days was significantly reduced at 6% vol/vol effluent concentration (P < 0.05). Flavor of yearling rainbow trout [Formula: see text] exposed to 3% effluent for 48 h was significantly impaired (P < 0.05). This effluent concentration, the lowest level impairing flavor represents approximately 0.12 of the 96-h LC50 derived from continuous-flow bioassays. No significant flavor impairment was detected in fish exposed for 144 h to a 2% effluent concentration Flavor impairment at a 3% vol/vol effluent concentration, the most sensitive sublethal response measured in this study, may also be the most critical response when assessing the economic impact of a kraft mill discharge to a freshwater ecosystem.


Aquaculture ◽  
1999 ◽  
Vol 180 (1-2) ◽  
pp. 79-87 ◽  
Author(s):  
J.H Blom ◽  
K Dabrowski ◽  
J.D Rapp ◽  
Y Sakakura ◽  
K Tsukamoto

1981 ◽  
Vol 38 (7) ◽  
pp. 739-743 ◽  
Author(s):  
A. B. McKague

Constituents responsible for the toxicity of a sample of bleached kraft chlorination-stage effluent to juvenile rainbow trout (Salmo gairdneri) were investigated. Tetrachlorocatechol, 3,4,5-trichlorocatechol, and 2,6-dichlorohydroquinone were identified and evidence was obtained for the presence of other chlorodihydroxybenzenes in toxic acidic fractions of the sample. Concentrations of 0.46 mg/L 3,4,5-trichloro- and 0.74 mg/L tetrachloro-catechol were estimated in the sample by analytical gas chromatography. Toxic materials in the nonacidic fraction were not identified although the nontoxic dichloromethyl methyl sulfone was isolated.Key words: chlorination-stage effluent, toxicity, pulp mill, chlorocatechols, chlorodihydroxybenzenes


1976 ◽  
Vol 33 (4) ◽  
pp. 1040-1045 ◽  
Author(s):  
C. B. Cowey

Dietary allowances of nutrients have been formulated mainly from growth–response curves. The use of other criteria, especially those which exploit the biochemical role of nutrients, is discussed by reference to three different nutrients, namely thiamin, magnesium, and essential fatty acids.It is shown that erythrocyte transketolase activity provides a nutritional index of thiamin status in turbot (Scophthalmus maximus). The enzyme is saturated with coenzyme (thiamin pyrophosphate) at a dietary thiamin level of 2.6 mg/kg.Assessment of mineral requirements is shown to present special problems because complex interrelationships exist between some dietary minerals. It is shown that dietary magnesium deficiency (4 mg magnesium/100 g diet) leads to renal calcification in rainbow trout (Salmo gairdneri) at dietary calcium levels of 2.7 g/100 g (Ca: P ratio 1: 1). Elevation of dietary magnesium to 100 mg/100 g under these conditions gave freedom from pathology and enhanced growth.Ratios of certain fatty acids in the tissue phospholipids of rainbow trout are known to provide a useful index of essential fatty acid status. These ratios cannot be applied to turbot as this species does not chain elongate and desaturate 18-carbon acids at appreciable rates. Long chain polyunsaturated fatty acids of the ω3 series must be supplied preformed in the diet of turbot.


1986 ◽  
Vol 56 (2) ◽  
pp. 421-428 ◽  
Author(s):  
J. G. Bell ◽  
J. W. Adron ◽  
C. B. Cowey

1. Duplicate groups of rainbow trout (Salmo gairdneri) were each given partially purified diets which were either adequate or depleted in selenium for 40 weeks.2. Although there was no significant difference in weight gain, liver Se concentration was significantly lower in fish given the deficient diet.3. Glutathione (GSH) peroxidase (EC 1. 11. 1. 9) activity was significantly reduced in liver of Se-deficient fish but a differential assay did not indicate the presence of a non-Se-dependent GSH peroxidase activity, although liver GSH S-transferase (EC 2. 5. 1. 18) was significantly increased.4. Perfusion of livers from trout given Se-adequate diets with t-butyl hydroperoxide (BuOOH) or hydrogen peroxide caused an increase in the rate of release of glutathione disulphide (GSSG) into the perfusate.5. Perfusion of livers from Se-deficient trout with BuOOH or H2O2 did not result in any change in rate of release of GSSG into the perfusate.6. These findings confirm the absence of any compensatory non-Se-dependent peroxidase activity in Se-depleted trout.


1986 ◽  
Vol 55 (2) ◽  
pp. 305-311 ◽  
Author(s):  
J. G. Bell ◽  
B. J. S. Pirie ◽  
J. W. Adron ◽  
C. B. Cowey

1. Two duplicate groups of rainbow trout (Sulmo gairdneri; mean weight 27 g) were given diets of differing selenium content (deficient 0, 025 mg Se/kg; supplemented 1.022 mg Se/kg) for 30 weeks.2. There were no significant differences between treatments in weight gain but packed cell volume, liver vitamin E and liver and plasma Se concentrations were all significantly lower in the Se-deficient trout.3. Ataxia occurred in about 10% of the Se-deficient trout and histopathologies were evident in nerve cord (damage to axon sheath) and liver (loss of integrity in endoplasmic reticulum and mitochondria with appearance of increased vesiculation).4. Glutathione peroxidase (EC 1.11.1.9) activity was significantly reduced in liver and plasma of Se-deficient fish but there was no indication, from differential assay, of any non-Se-dependent glutathione peroxidase activity. Glutathione transferase (EC 2.5. I.18) activity was significantly increased in Se-deficient trout.


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