Effects of Truttaedacnitis truttae (Nematoda: Cucullanidae) on growth and swimming of rainbow trout, Salmo gairdneri

1980 ◽  
Vol 58 (7) ◽  
pp. 1220-1226 ◽  
Author(s):  
L. R. Russell
Keyword(s):  
Rainbow Trout ◽  
Growth Rates ◽  
Growth Characteristics ◽  
Salmo Gairdneri ◽  
Food Conversion ◽  
Critical Swimming Speed ◽  
Nematode Parasites ◽  
Conversion Efficiencies ◽  
Similar Growth ◽  
Food Consumed

Growth and swimming abilities of fingerling and 1.5-year-old rainbow trout infected with the nematode parasite Truttaedacnitis truttae were examined. Control trout and trout infected in the laboratory with 5, 10, 20, 40, or 80 worms exhibited similar growth characteristics over a 10-week period within each of four experimental groups fed different rations of trout chow (1, 2, 3, or 4% of wet body weight fed per day). Decreasing growth rates showed some correlation with increasing numbers of nematode parasites. Differences between growth rates, amounts of food consumed, and food conversion efficiencies of infected and noninfected fish were not statistically significant. Critical swimming speed, fixed velocity, and burst velocity stamina tests revealed similar swimming abilities in both control and infected trout. Maximum swimming speeds attained and time to fatigue at cruising speeds were more closely related to fish size than to numbers of worms with which fish were infected. Importance to rainbow trout survival of large natural infections with T. truttae is discussed.

scholarly journals Effect of dietary protein level, and an anabolic steroid, ethylestrenol, on the growth, food conversion efficiency and protein efficiency ratio of rainbow trout (Salmo gairdneri)

1982 ◽  
Vol 47 (3) ◽  
pp. 615-624 ◽  
Author(s):  
B. W. Ince ◽  
K. P. Lone ◽  
A. J. Matty
Keyword(s):  
Rainbow Trout ◽  
G Protein ◽  
Anabolic Steroid ◽  
Dietary Protein ◽  
Protein Efficiency Ratio ◽  
Salmo Gairdneri ◽  
Food Conversion ◽  
Efficiency Ratio ◽  
Dietary Protein Level ◽  
Food Conversion Efficiency

1. Three isoenergetic test diets containing 320, 430 and 530 g protein/kg, with (experimental) and without (control) inclusion of an anabolic steroid, ethylestrenol, were given to rainbow trout (Salmo gairdneri) of mean initial weight 27 g, for 60 d.2. After 60 d, all trout groups were given an identical, steroid-free, commercial diet (410 g protein/kg) for a further 30 d, to observe withdrawal effects on growth.3. The weight and length of trout given the 430 and 530 g protein/kg control diets were significantly greater after 60 d than those given the 320 g protein/kg control diet.4. Inclusion of steroid enhanced the weight and length of trout given the 320 and 430 g protein/kg experimental diets, exerting a preferential effect on weight as opposed to length.5. After steroid withdrawal, a significant difference between the weight and length of the 320 g protein/kg control and experimental groups was still apparent.6. An increase in dietary protein increased the food conversion efficiency, and decreased the protein efficiency ratio. Inclusion of steroid increased both these factors over the respective controls.7. Protein assimilation decreased, and faecal nitrogen content increased with increasing dietary protein. In trout given steroid, protein assimilation and apparent digestibility was higher, and facecal N content, lower than the controls.8. Muscle protein increased with increasing dietary protein, and was higher in trout given steroid.9. Relative liver weight increased with increasing dietary protein. Inclusion of steroid resulted in a reduction in relative liver and gut weight, and an increase in kidney weight.10. It is concluded that ethylestrenol promotes both the growth and efficiency of nutrient utilization of trout. The magnitude and duration of these effects are a function of the dietary protein level.

Interpopulation differences in growth rates and food conversion efficiencies of young Grand Banks and Gulf of Maine Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (11) ◽  
pp. 2223-2229 ◽  
Author(s):  
Craig F Purchase ◽  
Joseph A Brown
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Larval Fish ◽  
Food Conversion ◽  
Life History Variation ◽  
Grand Banks ◽  
In The Wild ◽  
Conversion Efficiencies

Geographically separated Atlantic cod (Gadus morhua) stocks in the northwest Atlantic exhibit life history variation and have been shown to differ genetically. The genetic and environmental contributions to phenotypic differences, however, have not yet been measured. We used common environment experiments to evaluate the importance of temperature on the observed growth variation between Grand Banks (GB) and Gulf of Maine (GOM) cod stocks. Larvae from the GB grew faster than GOM larvae at both 7 and 12°C. Growth rates of juveniles were not different, but GB juveniles had higher food conversion efficiencies than those from the GOM (at both ambient and warm temperatures). The results indicate that faster growth of GOM cod in the wild is not due to a higher genetic capacity for growth rate in GOM than in GB fish. The findings give evidence of genetically based phenotypic variation, which is in agreement with molecular studies on population differentiation in cod, and support the theory of countergradient variation in growth rates of larval fish.

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

A note on the performance of artificially reared lambs fed cold milk substitute from birth to slaughter

1971 ◽  
Vol 13 (2) ◽  
pp. 365-368 ◽  
Author(s):  
P. D. Penning ◽  
P. G. E. Bradfield ◽  
T. T. Treacher
Keyword(s):  
Growth Rates ◽  
Dry Matter ◽  
Live Weight ◽  
Carcass Composition ◽  
Milk Replacer ◽  
Food Conversion ◽  
Milk Substitute ◽  
The Mean ◽  
Voluntary Intake ◽  
Conversion Efficiencies

SUMMARYTwo groups of five lambs were removed from their dams within 48 hr of birth and artificially reared to a slaughter weight of approximately 32 kg on a milk replacer given cold, hay and concentrates. Voluntary intake of the feeds was recorded together with growth rates and carcass composition of the lambs.The two groups of lambs were slaughtered at 58 or 67 days of age with growth rates of 459 and 433 g/day, respectively. The mean milk replacer dry matter consumed per lamb was 34·9 kg and 39·3 kg and concentrate dry matter intakes were 3·1 kg and 4·1 kg. Intakes of hay were negligible. Food conversion efficiencies were 0·70 and 0·67 kg of live-weight gain per kg of dry matter consumed. The mean carcass weights were 18·1 kg and 19·5 kg with mean muscle, bone and fat contents of 48·7%, 16·2% and 35·1 % for lambs slaughtered at 58 days and 48·0%, 14·7% and 37·2% for those slaughtered at 67 days.

Environmental Salinity: Its Failure to Influence Growth of Atlantic Salmon (Salmo salar) Parr

1975 ◽  
Vol 32 (10) ◽  
pp. 1821-1824 ◽  
Author(s):  
H. M. Shaw ◽  
R. L. Saunders ◽  
H. C. Hall
Keyword(s):  
Body Weight ◽  
Atlantic Salmon ◽  
Fresh Water ◽  
Salmo Salar ◽  
Growth Rates ◽  
Food Conversion ◽  
Instantaneous Growth ◽  
Atlantic Salmon Salmo Salar ◽  
Conversion Efficiencies ◽  
Maintenance Ration

Growth of Atlantic salmon (Salmo salar) parr was studied at environmental salinities of 0.1, 10, and 20‰ in relation to daily rations of 0, 1.0, 1.5, 2.2, and 2.9% of dry body weight. Instantaneous growth rates and food conversion efficiencies for fish in each salinity were similar. Maintenance ration was slightly more in 20‰ than in either the salinity approximately isosmotic with blood (10%) or in fresh water (0.1%).

Sublethal Toxicity of Cyanide to Rainbow Trout (Salmo gairdneri) at Different Temperatures

1982 ◽  
Vol 39 (10) ◽  
pp. 1389-1395 ◽  
Author(s):  
Tibor G. Kovacs ◽  
Gérard Leduc
Keyword(s):  
Rainbow Trout ◽  
Growth Rates ◽  
Swimming Performance ◽  
Dry Weight ◽  
Liver Glycogen ◽  
Salmo Gairdneri ◽  
Sublethal Toxicity ◽  
Different Temperatures ◽  
Wet Weight ◽  
Flow Through

At sublethal levels cyanide was more potent at lower temperatures. This was verified in 20-d laboratory growth experiments carried out on juvenile rainbow trout (Salmo gairdneri) in flow-through aquaria maintained at 6, 12, and 18 °C. Cyanide concentrations in the range of 0.005–0.045 mg∙L−1 HCN significantly reduced growth rates (wet weight, dry weight, and fat), the effective concentrations increasing with temperature. Some adaptation to cyanide seemed to occur as manifested by faster growth rates. Liver glycogen and lactic acid monitored for 20 d in rainbow trout exposed to 0.015 mg∙L−1 HCN showed an initial shift towards glycolysis, followed by a return to aerobic respiration. This response, however, varied with temperatures. Previous exposure to cyanide markedly reduced swimming performance of the fish tested at their acclimation temperatures, but in the absence of the toxicant. The effect also increased with decreasing temperatures.Key words: cyanide, sublethal toxicity, rainbow trout, temperature, growth, swimming, liver metabolites

An Initial Evaluation of Ethylene Oxide for the Sterilization of Formulated and Pelleted Fish Feeds

1973 ◽  
Vol 30 (2) ◽  
pp. 269-274 ◽  
Author(s):  
T. J. Trust ◽  
A. J. Wood
Keyword(s):  
Carbon Dioxide ◽  
Rainbow Trout ◽  
Ethylene Oxide ◽  
Growth Rates ◽  
Initial Evaluation ◽  
Salmo Gairdneri ◽  
Gas Mixture ◽  
Carbon Dioxide Gas ◽  
Fish Feeds ◽  
Better Than

Satisfactory sterilization of dried pelleted fish foods was achieved with an ethylene oxide–carbon dioxide gas mixture (20:80). The growth rates of juvenile rainbow trout (Salmo gairdneri) fed on feed so sterilized were comparable to or better than those of trout fed the same feed not sterilized.

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