scholarly journals Studies on the nutrition of salmonid fish. The magnesium requirement of rainbow trout (Salmo gairdneri)

1981 ◽  
Vol 45 (1) ◽  
pp. 137-148 ◽  
Author(s):  
D. Knox ◽  
C. B. Cowey ◽  
J. W. Adron
Keyword(s):  
Rainbow Trout ◽  
Weight Gain ◽  
Extracellular Fluid ◽  
Salmo Gairdneri ◽  
Initial Weight ◽  
Muscle Water ◽  
Low Levels ◽  
K Concentration ◽  
Dry Diet ◽  
Dietary Treatments

1. Rainbow trout (Salmo gairdneri) of mean initial weight 35 g were given one of five experimental diets for 20 weeks. The diets contained (g/kg dry diet) 15 calcium, 10 phosphorus and graded levels of magnesium from 0.04 (diet no. 1) to 1.0 (diet no. 5). In a second experiment rainbow trout of mean initial weight 16 g were given one of six experimental diets for 20 weeks. The diets contained (g/kg dry diet): Ca (40), P (30) and levels of Mg from 0.06 (diet no. 6) to 2.0 (diet no. 11).2. In both experiments weight gains were lowest in those trout given diets containing the basal levels of Mg (diet no. 1 and diet no. 6) but increased with increasing dietary Mg concentration. In neither experiment was there any further increase in weight gain once the Mg concentration reached 0.25–0.5 g/kg dry diet; weight gain reached a plateau at this dietary Mg level.3. The following trends occurred in serum electrolyte concentrations as dietary Mg increased. Mg increased in both experiments, in Expt 2 it reached a maximum of 1 mmol/l when the diet containted 0.5 g Mg/kg and did not increase further; sodium was positively correlated in both experiments; potassium decreased and in Expt 2 reached a plateau minimum of 1.7 mmol/l at a dietary Mg concentration of 0.5 g/kg; Ca and P altered little in either experiment.4. In both experiments renal Ca concentrations were greatly increased in trout given diets lacking supplementary Mg; they fell to low levels (3–5 mmol/kg) when diets conained 0.15 g Mg/kg or more. Renal K and P concentrations were negatively correlated with dietary Mg in Expt 2; other electrolytes measured were not altered in concentration by the treatments used.5. Extracellular fluid volume (ECFV) of muscle was negatively correlated with dietary Mg. In Expt 2 it reached a minimal or normal value at 0.5 g Mg/kg diet and did not decease further. Muscle Mg concentration increased with diet Mg in both experiments and muscle K concentration was also correlated with diet Mg in Expt 2. These changes were related to the shift in muscle water. In Expt 1, P concentration was decreased with increasing diet Mg but in Expt 2 its concentration increased, these changes may have been connected with the three-fold difference in dietary P in the two experiments.6. By contrast with skeletal muscle, Mg levels in cardiac muscle increased at low dietary Mg intakes.7. Concentrations of electrolytes in liver did not alter with dietary treatments used.8. The results show that Mg requirement of rainbow trout is met by a diet containing 0.5 g Mg/kg diet.

scholarly journals The production of renal calcinosis by magnesium deficiency in rainbow trout (Salmo gairdneri)

1977 ◽  
Vol 38 (1) ◽  
pp. 127-135 ◽  
Author(s):  
C. B. Cowey ◽  
D. Knox ◽  
J. W. Adron ◽  
S. George ◽  
B. Pirie
Keyword(s):  
Rainbow Trout ◽  
Magnesium Deficiency ◽  
Light And Electron Microscopy ◽  
Extracellular Fluid ◽  
Renal Calculi ◽  
Salmo Gairdneri ◽  
List Type ◽  
Calcium Phosphorus ◽  
Dietary Treatments ◽  
Micro Analysis

1.Replicate groups of rainbow trout (Salmo gairdneri) were given one of five experimental diets (diets 1-5) for 16 weeks. The diets contained different amounts of calcium, phosphorus and magnesium and were prepared so that there were three levels of Ca (g/kg): 14 (diet 1), 26 (diets 2 and 3) and 40 (diets 4 and 5), Ca:P being approximately 1:1 in all diets. Diets 1, 2 and 4 had basal Mg levels (not more than 0.063 g/kg) whereas diets 3 and 5 contained supplementary Mg (1.0 g/kg).2.Weight gains of the trout given diets containing supplementary Mg were twice those of trout given diets with basal levels of Mg. At both dietary Mg concentrations weight gain was unaffected by the dietary Ca level.3.Serum Mg levels were significantly reduced in those trout given diets without supplementary Mg. The serum Ca level in those trout given the lowest concentration of Ca in their diet (14 g/kg, diet 1) was significantly greater than in those given higher amounts of Ca in their diets. Serum P levels were not significantly different with any of the experimental diets.4.The renal Ca concentration was increased in trout given diet 3 (26 g Ca/kg; basal Mg levels). No further increase in renal Ca concentration occurred in trout given diet 5 (40 g Ca/kg; basal Mg levels). With diets containing supplementary Mg renal Ca levels were increased at a dietary Ca level of 40 g/kg but not at a dietary Ca level of 26 g/kg. Renal Mg and P concentrations were not significantly different between any of the dietary treatments.5.Renal calculi were demonstrated by light and electron microscopy in tubules of those trout given diets 3 and 5 (basal Mg; 26 and 40 g Ca/kg respectively). Electron-probe micro-analysis showed that these calculi contained or comprised tricalcium phosphate.6.The skeletal muscle of Mg-deficient trout contained significantly more sodium than that of normal trout. It is suggested that this is indicative of an increase in extracellular fluid in the muscle of Mg-deficient trout.

scholarly journals The effect of vitamin E and oxidized fish oil on the nutrition of rainbow trout (Salmo gairdneri) grown at natural, varying water temperatures

1984 ◽  
Vol 51 (3) ◽  
pp. 443-451 ◽  
Author(s):  
C. B. Cowey ◽  
Elizabeth Degener ◽  
A. G. J. Tacon ◽  
A. Youngson ◽  
J. G. Bell
Keyword(s):  
Rainbow Trout ◽  
Weight Gain ◽  
Vitamin E ◽  
Fish Oil ◽  
Water Temperature ◽  
Tocopheryl Acetate ◽  
Salmo Gairdneri ◽  
Oxidized Oil ◽  
Dietary Treatments ◽  
Oxidized Fish Oil

1. Groups of rainbow trout (Salmo gairdneri) of approximate mean initial weight 8 g were grown in outdoor tanks over a 14-week period at water temperatures between 12° (start) and 6° (end). Four diets were used. Two contained non-oxidized fish oil (120 g/kg) with or without supplementary DL-α tocopheryl acetate and two contained moderately oxidized fish oil again with or without DL-α-tocopheryl acetate. The measured selenium content of the diets was 0.10 mg/kg.2. No significant differences occurred as a consequence of the use of moderately oxidized oil compared with the corresponding treatments using non-oxidized oil. Significant differences did occur between dietary treatments that contained supplementary DL-α-tocopheryl acetate and those that did not. These differences applied to weight gain, haematocrit, erythrocyte fragility, mortalities, liver and muscle tocopherol concentrations and lipid peroxidation of liver mitochondria in vitro. Liver glutathione peroxidase (EC 1.11.1.9) activity was unaffected by the dietary treatments used and the proportions of fatty acids in polar lipids of liver and muscle were little changed by the diets used. Severe muscle damage occurred in trout given diets lacking supplementary DL-α-tocopheryl acetate.3. Previous experiments carried out on rainbow trout at a constant water temperature of 15° (Hung et al. 1981; Cowey et al. 1981, 1983), using diets lacking supplementary vitamin E, did not lead to differences in weight gain, pathological changes or mortalities.4. Vitamin E requirement may increase as water temperature decreases; minimum dietary requirements for vitamin E measured at a constant water temperature of 15° may not be valid under practical conditions where water temperatures vary over the year.

scholarly journals The effect of dietary lysine levels on growth and metabolism of rainbow trout (Salmo gairdneri)

1984 ◽  
Vol 52 (1) ◽  
pp. 115-122 ◽  
Author(s):  
M. J. Walton ◽  
C. B. Cowey ◽  
J. W. Adron
Keyword(s):  
Rainbow Trout ◽  
Intraperitoneal Injection ◽  
Response Curve ◽  
Salmo Gairdneri ◽  
Hepatosomatic Index ◽  
Dietary Requirement ◽  
Saccharopine Dehydrogenase ◽  
Lysine Concentration ◽  
Low Levels ◽  
Dietary Treatments

1. Groups of rainbow trout (Salmo gairdneri; mean weight 5 g) were given diets containing 10, 12, 14, 17, 21, 24 and 26 g lysine/kg diet for 12 weeks.2. By analysis of the growth values the dietary requirement of lysine in this experiment was found to be 19 g/kg diet. A similar requirement value was obtained from a dose-response curve of expired 14CO2 (following an intraperitoneal injection of L-[U-14C]lysine) v. dietary lysine concentration.3. Liver concentrations of total lipid and carnitine and activities of lysine-α-ketoglutarate reductase (saccharopine dehydrogenase (NADP+, lysine-forming), EC 1. 5. 1. 8 ) in the liver were not significantly different in fish from the different dietary treatments. Hepatosomatic index, however, was higher in those fish given low levels of dietary lysine.

scholarly journals The effect of low dietary manganese intake on rainbow trout (Salmo gairdneri)

1981 ◽  
Vol 46 (3) ◽  
pp. 495-501 ◽  
Author(s):  
D. Knox ◽  
C. B. Cowey ◽  
J. W. Adron
Keyword(s):  
Superoxide Dismutase ◽  
Rainbow Trout ◽  
Packed Cell Volume ◽  
Control Diet ◽  
Haemoglobin Concentration ◽  
Plasma Potassium ◽  
Salmo Gairdneri ◽  
Feeding Period ◽  
Initial Weight ◽  
Dry Diet

1. Rainbow trout (Salmo gairdneri) of mean initial weight 15 g were given either a low-manganese or control diet containing 1·3 and 33 mg Mn/kg dry diet respectively.2. Weight gains over a 24-week feeding period were the same for both groups of trout.3. Hepatosomalic index, blood packed cell volume and haemoglobin concentration, plasma protein and the activities of aspartic aminotransferase(EC 2.6.1.1)and alanine aminotransferase(EC 2.6.1.2) were unaffected by dietary Mn intake.4. Plasma potassium and iron levels were increased in the trout given the low-Mn diet.5. The hepatic levels of magnesium, sodium, K, zinc, copper, Mn and phosphorus were significantly reduced in the fish given the low-Mn diet.6. In those trout given the low-Mn diet the levels of Mn and calcium in the vertebral ash were significantly reduced.7. The hepatic activity of Cu-Zn superoxide dismutase (EC 1.15.1.1; Cu–ZnSOD) and of Mn superoxide dismutase (EC 1.15.1.1; MnSOD) in cardiac muscle and liver was reduced in the group of trout given the low-Mn diet. The fall in Cu–ZnSOD and MnSOD activities coincided with reduced tissue levels of their respective metal components.

Embryonic Development, Early Growth, and Meristic Variation in Rainbow Trout (Salmo gairdneri) Exposed to Combinations of Light Intensity and Temperature

1975 ◽  
Vol 32 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Wen-hwa Kwain
Keyword(s):  
Rainbow Trout ◽  
Embryonic Development ◽  
Mortality Rates ◽  
Early Growth ◽  
Development Rate ◽  
Salmo Gairdneri ◽  
Initial Weight ◽  
Light Intensities ◽  
Incubation Periods ◽  
Meristic Variation

Lowest mortality rates of rainbow trout (Salmo gairdneri) embryos were obtained at temperatures of 7 and 10 C and light intensities of 0.2 and 20 lx. Temperatures of 3 and 15 C and an intensity of 400 lx were near the thresholds for development. Eggs exposed to 0.2 lx required 111 days to reach 50% hatch at 3 C, but 26 days at 15 C; those exposed to 20 lx, 97 days at 3 C and 25 days at 15 C.Growth rates of rainbow trout 145 days after hatch were significantly different (P < 0.05) at 10 and 3 C, and 20, 2, and 0.2 lx. The fastest growth occurred at 10 C and 2 lx, and the lowest growth at 3 C and 0.2 lx. For increment of body weight it was about 23.8%/day of initial weight and 6.6% at 3 C. At light intensities of 20, 2, and 0.2 lx, the rate per day was 24.7, 17.2, and 11.2%, respectively. However, increases in length occurred at a much reduced rate.Variations in numbers of vertebrae, gill rakers, and fin rays were positively correlated with the embryonic development rate. Longer incubation periods were usually associated with more meristic elements, regardless of the environmental factors involved.

scholarly journals Effect of selenium deficiency on hydroperoxide-stimulated release of glutathione from isolated perfused liver of rainbow trout (Salmo gairdneri)

1986 ◽  
Vol 56 (2) ◽  
pp. 421-428 ◽  
Author(s):  
J. G. Bell ◽  
J. W. Adron ◽  
C. B. Cowey
Keyword(s):  
Hydrogen Peroxide ◽  
Rainbow Trout ◽  
Weight Gain ◽  
Peroxidase Activity ◽  
Selenium Deficiency ◽  
Salmo Gairdneri ◽  
Perfused Liver ◽  
Deficient Diet ◽  
Significant Difference ◽  
Glutathione Disulphide

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.

Turnover and Urinary Excretion of Free and Acetylated M.S. 222 by Rainbow Trout, Salmo gairdneri

1968 ◽  
Vol 25 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Joseph B. Hunn ◽  
Richard A. Schoettger ◽  
Wayne A. Willford
Keyword(s):  
Rainbow Trout ◽  
Aromatic Amines ◽  
Recovery Period ◽  
Free Drug ◽  
Salmo Gairdneri ◽  
Blood Levels ◽  
Drug Elimination ◽  
Drug Excretion ◽  
Anesthetic Concentration ◽  
Low Levels

Rainbow trout: (Salmo gairdneri) anesthetized in 100 mg/liter of M.S. 222 at 12 C excreted the drug in free and acetylated forms via the urine during a 24-hr recovery period in freshwater. Of the M.S. 222 excreted, 77–96% was acetylated. Blood levels of free drug in anesthetized trout approximated 75% of the anesthetic concentration, but the amount of acetylated M.S. 222 was relatively insignificant. The blood and urine were cleared of the two fractions of M.S. 222 in 8 and 24 hr respectively. Low levels of aromatic amines of natural origin occurred in blood and urine and were subtracted from measurements of M.S. 222. Intraperitoneal injections of 10–100 mg/kg of M.S. 222 did not induce anesthesia; however, the 24-hr pattern of drug excretion was similar to that observed after anesthesia by immersion. Only 15–21% of the injected dose was found in the urine, suggesting a second route of drug elimination.

scholarly journals Some effects of selenium deficiency on glutathione peroxidase (EC 1.11.1.9) activity and tissue pathology in rainbow trout (Salmo gairdneri)

1986 ◽  
Vol 55 (2) ◽  
pp. 305-311 ◽  
Author(s):  
J. G. Bell ◽  
B. J. S. Pirie ◽  
J. W. Adron ◽  
C. B. Cowey
Keyword(s):  
Endoplasmic Reticulum ◽  
Rainbow Trout ◽  
Weight Gain ◽  
Vitamin E ◽  
Glutathione Peroxidase ◽  
Glutathione Transferase ◽  
Selenium Deficiency ◽  
Salmo Gairdneri ◽  
Selenium Content ◽  
Glutathione Peroxidase Activity

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.

A Study of in vivo Glycine Absorption by Fed and Fasted Rainbow Trout (Salmo Gairdneri)

1981 ◽  
Vol 91 (1) ◽  
pp. 285-292 ◽  
Author(s):  
G. BOGÉ ◽  
A. RIGAL ◽  
G. PÉRES
Keyword(s):  
Body Weight ◽  
Rainbow Trout ◽  
Weight Gain ◽  
Amino Acid ◽  
Acid Concentration ◽  
Dry Weight ◽  
Salmo Gairdneri ◽  
Mucosal Tissue ◽  
Perfusion Technique

The effects of 4 and 8 weeks fasting at 16 °C were studied in rainbow trout, Salmo gairdneri Richardson. After 4 and 8 weeks, the wet weights of the intestine of fasted animals are respectively 64% and 69% lower than those of fed animals. These effects especially concern the mucosal tissue. Glycine absorption (0.5 and 10 mm) was studied using an in vivo perfusion technique. After 4 weeks, the absolute amounts of 0.5 mm glycine absorbed by fasted and fed fish are similar. With 10 mm glycine, the absorption is slightly lower in fasted trout (−19%). After 8 weeks these differences are more marked, with glycine concentrations of 10 mm (−42%). Results expressed per 100 g body weight showed that these differences result partly from a weight gain of fed trout. Absorption expressed in terms of weight of dry intestine is higher in 4 and 8 weeks fasted animals, principally for the lower amino acid concentration (+61% and +111%). Larger differences were apparent when the absorptions were expressed in terms of dry weight of mucosal tissue (+122% and +225%).

Acceptability of Rapeseed Proteins in Diets of Rainbow Trout (Salmo gairdneri)

1978 ◽  
Vol 35 (7) ◽  
pp. 951-962 ◽  
Author(s):  
M. Yurkowski ◽  
J. K. Bailey ◽  
R. E. Evans ◽  
Jo-Anne L. Tabachek ◽  
G. Burton Ayles ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Rainbow Trout ◽  
Weight Gain ◽  
Liver Weight ◽  
Rapeseed Meal ◽  
Economic Benefits ◽  
The Body ◽  
Feed Consumption ◽  
Salmo Gairdneri ◽  
Rapeseed Proteins

Weight gain and feed consumption results showed that rapeseed protein concentrate (RPC) and rapeseed meal (RM) can be substituted for soybean meal (SM) and perhaps partially for herring meal (HM) in rainbow trout (Salmo gairdneri) control (SM–HM) diet and thus have economic benefits. Rapeseed flour (RF) was a poor source of proteins due to its greater effect on thyroid function. Rapeseed proteins have little effect on liver weight, body moisture, liver and body lipid, liver and body sterol content, visual and histological appearance of liver, heart and visceral tissues, or on the flavor, but caused yellow pigmentation of the skin. The levels of individual fatty acids in the diets directly affected the levels of individual fatty acids in the liver and body, while the type and level of dietary rapeseed proteins appeared to have no effect. The levels of fatty acids, 20:1 and 22:1 (includes erucic acid), were lower in the body and even lower in the liver compared with the diets. All test diets, except RPC–HM diet, caused marked thyroid hyperplasia, believed to be due to glucosinolates (goitrogens). However, some compensation for this goitrogenic action must occur because plasma T4 levels indicated a hypothyroid state for only five test diets (highest RPC-containing diet; highest RM-containing diet; all three RF-containing diets). Key words: dietary rapeseed, glucosinolates, feed–gain ratios, growth, lipids, fatty acids, plasma T4, thyroid histology, flavor, weight gain

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