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.

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.

Hematological Aspects of the Thermoacclimatory Process in the Rainbow Trout, Salmo gairdneri

1967 ◽  
Vol 24 (11) ◽  
pp. 2267-2281 ◽  
Author(s):  
Mary Anne DeWilde ◽  
A. H. Houston
Keyword(s):  
Rainbow Trout ◽  
General Problem ◽  
Carrying Capacity ◽  
Packed Cell Volume ◽  
Salmo Gairdneri ◽  
Blood Oxygen ◽  
Hemoglobin Content ◽  
Oxygen Capacity ◽  
Higher Temperature ◽  
Oxygen Carrying Capacity

The blood oxygen capacity of the rainbow trout has been investigated as a function of thermal acclimation in terms of erythrocyte abundance, packed cell volume, hemoglobin concentrations, and mean erythrocytic volume and hemoglobin content. Fish at the lower acclimation temperatures employed (3, 7 C) were characterized by relatively low erythrocyte counts, hematocrits, and hemoglobin levels. Mean erythrocyte volumes tended to be relatively high, whereas mean erythrocytic hemoglobin content was somewhat below that typical of the higher temperature groups. In general, animals held at intermediate temperatures (11, 14, 17 C) showed significant increases in oxygen-carrying capacity by comparison with cold-acclimated fish. Finally trout at 21 C typically had larger numbers of somewhat smaller red cells, more hemoglobin, and higher levels of hemoglobin per erythrocyte than either the low- or intermediate-temperature fish. Significant differences were observed between summer and fall–winter series of trout, particularly with respect to hemoglobin levels. The results are discussed in relation to the general problem of respiratory thermoadaptation.

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.

Effect of Diet on the Immune Response of Rainbow Trout (Salmo gairdneri)

1984 ◽  
Vol 41 (8) ◽  
pp. 1244-1247 ◽  
Author(s):  
Vicki S. Blazer ◽  
Richard E. Wolke
Keyword(s):  
Immune Response ◽  
Rainbow Trout ◽  
Control Diet ◽  
Serum Antibody ◽  
Peritoneal Macrophages ◽  
Salmo Gairdneri ◽  
Yersinia Ruckeri ◽  
Nonspecific Resistance ◽  
Commercial Diet ◽  
T Cell Migration

To compare the effect of diet on the immune response of rainbow trout (Salmo gairdneri), we maintained fish on either a commercial feed or a laboratory prepared (control) diet for 12–16 wk before antigenic exposure. The immune response to two antigens, sheep red blood cells (SRBC) and Yersinia ruckeri, was assessed. Both T-cell (migration inhibition factor) and B-cell (plaque-forming cell) responses to SRBC were measured. The plaque-forming cell response and the humoral (serum antibody) responses to Y. ruckeri were assayed. In addition, the phagocytic ability of peritoneal macrophages was assessed as a nonspecific resistance factor. We found that fish maintained on the commercial diet had a significantly lower immune response when compared with fish fed the control diet, although all fish appeared healthy and suffered no mortalities throughout the experiment. We indicate the importance of considering the effects of diet on immunity and disease resistance in future feed formulations.

Ecophysiology and Mercury Accumulation of Rainbow Trout (Salmo gairdneri) When Exposed to Mercury in Various Concentrations of Chloride

1986 ◽  
Vol 43 (3) ◽  
pp. 710-714 ◽  
Author(s):  
Barbara Z. Walczak ◽  
U. Theodore Hammer ◽  
P. Ming Huang
Keyword(s):  
Rainbow Trout ◽  
Chloride Concentration ◽  
Plasma Potassium ◽  
Salmo Gairdneri ◽  
Plasma Sodium ◽  
Mercury Accumulation ◽  
Cell Counts ◽  
Plasma Sodium Level ◽  
White Blood Cell Counts ◽  
Chloride Concentrations

Rainbow trout (Salmo gairdneri) mortality was 100% when exposed to HgCl2 (2–10 μg∙Hg2+∙L−1) for 14 d in a natural low chloride medium. There was no mortality if the medium contained 100, 200, or 400 mg Cl−∙L−1 or more. Accumulation of mercury was highest in kidneys (0.65–13 μg∙g−1), spleen (0.31–4.2), gills (0.46–4.15), and liver (0.53–2.1) but accumulations differed for periods of exposure (14 or 42 d) and chloride concentration in the medium (100 or 200 mg Cl−∙L−1). In rainbow trout exposed to HgCl2 for 42 d, there were significant increases in plasma sodium level at 200 mg Cl−∙L−1 and significant decreases in plasma potassium, albumin, α1-globulin, and β-globulin levels in 100 mg Cl−∙L−1. No significant changes occurred in these parameters at other chloride concentrations or in erythrocytes, hematocrit, mean corpuscular volume, white blood cell counts, or chloride plasma levels. Although chloride concentrations in the media affect mercury accumulation by different organs as well as affecting physiological functions, there appears to be no direct relationship except for reduced mortality.

Canola Meal in Rainbow Trout (Salmo gairdneri) Production Diets

1983 ◽  
Vol 40 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Ronald W. Hardy ◽  
Craig V. Sullivan
Keyword(s):  
Rainbow Trout ◽  
Weight Gain ◽  
Thyroid Function ◽  
Control Diet ◽  
Normal Growth ◽  
Salmo Gairdneri ◽  
Canola Meal ◽  
Future Research ◽  
Food Conversion ◽  
Organoleptic Quality

Production diets containing up to 20% canola meal were fed for 108 d to rainbow trout (Salmo gairdneri) to evaluate the effects on weight gain, food conversion, thyroid function, and organoleptic quality of market-sized fish. Weight gain was not affected by dietary canola meal level. Food conversion values and organoleptic properties were not influenced by dietary treatments. Feed costs were reduced by $18.70 (U.S.) per metric ton compared to control diet at the highest level of dietary canola meal (20%). Thyroid function was significantly affected by dietary canola meal. Dose-related changes in the histological appearance of the thyroid and alterations of plasma thyroxine and 3,5,3′-triiodothyronine levels indicated that compensatory adjustments in thyroid function allowed normal growth to proceed in the canola-fed fish. Possible mechanisms of dietary glucosinolate influence on thyroid function are discussed and areas for future research are suggested.Key words: canola meal, plasma T4, plasma T3, thyroid histology, goitrogen, glucosinolates, trout growth, food conversion, least-cost diets, organoleptic quality

scholarly journals Free and Total Calcium Concentrations in the Blood of Rainbow Trout, Salmo Gairdneri, During ‘Stress’ Conditions

1985 ◽  
Vol 118 (1) ◽  
pp. 111-120
Author(s):  
PETER ANDREASEN
Keyword(s):  
Rainbow Trout ◽  
Protein Concentration ◽  
Narrow Range ◽  
Haemoglobin Concentration ◽  
Stress Conditions ◽  
Salmo Gairdneri ◽  
Total Calcium ◽  
Plasma Protein Concentration ◽  
Acid Base Status ◽  
Intense Activity

Measurements were made of the free and total calcium concentrations ([Ca2+] and Cat), acid-base status, haemoglobin concentration, haematocrit and plasma protein concentration in the blood of the rainbow trout, Salmo gairdneri. In isolated blood, [Ca2+] was proportional to Cat while log[Ca2+] was inversely proportional to pH. Similar findings have been reported from human blood. During intense activity, [Ca2+] increased by 16% without any significant change in Cat. Neither sustained exercise, hypercapnic acidosis nor hypoxia affected [Ca2+] or Cat. These data indicate that during common natural stress conditions [Ca2+] is maintained within a narrow range.

scholarly journals Studies on the nutrition of rainbow trout (Salmo gairdneri) Magnesium deficiency: the effect of feeding with a Mg-supplemented diet

1983 ◽  
Vol 50 (1) ◽  
pp. 121-127 ◽  
Author(s):  
D. Knox ◽  
C. B. Cowey ◽  
J. W. Adron
Keyword(s):  
Rainbow Trout ◽  
Magnesium Deficiency ◽  
Control Diet ◽  
Plasma Concentrations ◽  
Complete Recovery ◽  
Salmo Gairdneri ◽  
Control Group ◽  
Deficient Diet ◽  
Bone Ash ◽  
And Control

1. For a period of 8 weeks, rainbow trout (Salmo gairdneri), mean initial weight 21 g, were given either a low-magnesium or control diet containing 0·03 and 0·58 g Mg/kg diet respectively. Both groups of trout were then given the control diet for a further 11 weeks.2. Weight gains over the initial 8-week period were lowest in the Mg-deficient trout. Feeding the deficient fish the control diet rapidly improved growth rate until it was the same as that of the control trout.3. Plasma Mg was significantly lower in the Mg-deficient trout at week 8. Feeding with the control diet for 11 weeks did not increase plasma Mg. Few changes were observed in the plasma concentrations of the other electrolytes.4. Renal calcium concentrations were unaffected by dietary Mg levels. Similarly, the renal levels of phosphorus, sodium and potassium all fell within the range found in normal rainbow trout.5. Muscle Mg concentrations were reduced in those trout given the Mg-deficient diet. Feeding with the control diet for a further 11 weeks increased muscle Mg but the level was still significantly lower than that found in trout given the control diet for 19 weeks.6. The bone ash Mg concentration was significantly lower, and the Ca higher, in the deficient fish at week 8, when compared with the control group.7. When compared with the value at the start of the experiment, total bone Mg fell slightly in the deficient trout over the initial 8-week period, but increased in the control group of fish. Feeding with the control diet for a further 11 weeks increased total bone Mg in both Mg-deficient trout and control trout.8. The results show that the Mg deficiency imposed on the rainbow trout was of limited severity and almost complete recovery was obtained when the control diet was fed.

scholarly journals Effects of Hot and Sweet Red Peppers (Capsicum annuum) as Feed Supplements on Pigmentation, Sensory Properties and Weight Gain of Rainbow Trout (Onchorhynchus mykiss)

2016 ◽  
Vol 16 (3) ◽  
pp. 825-834 ◽  
Author(s):  
Mahmut Yanar ◽  
Hakan Murat Büyükçapar ◽  
Yasemen Yanar
Keyword(s):  
Rainbow Trout ◽  
Weight Gain ◽  
Control Diet ◽  
Fish Muscle ◽  
Sensory Properties ◽  
Red Pepper ◽  
Control Group ◽  
Initial Weight ◽  
Carotenoid Accumulation ◽  
Red Peppers

AbstractThis study was conducted to evaluate the effects of diets, including 0.5, 2 and 4.4% dried hot or sweet red pepper and a control diet without added red pepper, on pigmentation, sensory properties and weight gain of rainbow trout, with average initial weight of 60 g, for a rearing period of 80 days. Both red pepper types had similar effects on the carotenoid accumulation, weight gain and sensorial properties of the fish (P>0.05). Total carotenoid accumulation in the fish muscle increased significantly with increasing inclusion of red peppers. However, only the diet consisting of 4.4% hot or sweet red pepper provided adequate carotenoid accumulation in the fillet of the fish, that is, the desired colouration in the fish. Fish fed diets containing red peppers exhibited higher appearance and colour scores compared to control group (P<0.05). Irrespective of being hot or sweet, red pepper can be successfully used as an alternative natural carotenoid source in rainbow trout diets.

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