Effect of different acidified wet feeds on protease activities in the digestive tract and on growth rate of rainbow trout (Salmo gairdneri Richardson)

Aquaculture ◽  
1981 ◽  
Vol 22 ◽  
pp. 67-79 ◽  
Author(s):  
Krisna Rungruangsak ◽  
Finn Utne
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Digestive Tract ◽  
Salmo Gairdneri

Differences in Swimming Performance Among Strains of Rainbow Trout (Salmo gairdneri)

1977 ◽  
Vol 34 (2) ◽  
pp. 304-307 ◽  
Author(s):  
Allan E. Thomas ◽  
Michael J. Donahoo
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
New Zealand ◽  
Swimming Performance ◽  
Salmo Gairdneri ◽  
Swimming Ability ◽  
Fish Swimming ◽  
Fish Size ◽  
Swimming Time ◽  
Performance Profiles

Swimming performance profiles, relating fish size to swimming time, were established for three strains of rainbow trout (Salmo gairdneri). No differences were found in slope of regressions; only in level at each size of fish. Swimming performances of New Zealand and Sand Creek strains did not differ, but were superior to the Manchester strain. In stamina results from 189-day-old fish from individual matings of seven strains and various crosses, similar strains and crosses had closely matching profiles whereas profiles of unrelated groups were variable. Comparison of slowest, average, and fastest growing fish within the New Zealand strain showed that swimming ability was not related to growth rate.

Effect of Growth Rate and Size of Fish on Rate of Intoxication by Waterfoorne Lead

1982 ◽  
Vol 39 (9) ◽  
pp. 1243-1251 ◽  
Author(s):  
Peter V. Hodson ◽  
D. George Dixon ◽  
Douglas J. Spry ◽  
D. M. Whittle ◽  
John B. Sprague
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Lake Trout ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Small Fish ◽  
Rainbow Smelt ◽  
Fish Size ◽  
Threshold Size ◽  
Juvenile Rainbow Trout

Three experiments were undertaken to test the null hypotheses that increasing fish size and growth rate do not increase the rate of intoxication of fish by lead. The first experiment demonstrated that there were no significant correlations between weight of fish and either whole-body or blood lead concentrations in feral lake trout (Salvelinus namaycush). The whole-body lead concentration of rainbow smelt (Osmerus mordax) was, however, negatively correlated to wet weight.During the second experiment, an 8-d laboratory exposure of rainbow trout (Salmo gairdneri) to 100 μg/L of total waterborne lead caused a greater uptake of lead by opercular bone in small fish than in larger fish. No relationship was apparent between fish weight and uptake of lead by blood.Chronic exposure of juvenile rainbow trout to lead results in the development of black tails, a symptom of neurotoxicity. The final experiment related the incidence and prevalence of black tails to size and growth rate (ration level) of juvenile rainbow trout chronically exposed to 543 μg/L of total waterborne lead starting with the sac-fry stage. At weights below a common threshold size of 1.5–2.5 g, no black tails occurred; above this threshold the incidence of black tails was a function of growth rate, i.e. the rate at which fish reached the threshold size. The prevalence of black tails was always less in slowly growing fish.These experiments demonstrated that the rate of intoxication by lead, as indicated by uptake rates into tissues and the incidence and prevalence of a symptom of neurotoxicity, did not increase with fish size, but rather with growth rate.Key words: fish, toxicity, lead, fish size, growth rate, neurotoxicity, uptake

Effects of Constant Temperatures and Diel Temperature Fluctuations on Specific Growth and Mortality Rates and Yield of Juvenile Rainbow Trout, Salmo gairdneri

1977 ◽  
Vol 34 (5) ◽  
pp. 639-648 ◽  
Author(s):  
Kenneth E. F. Hokanson ◽  
Charles F. Kleiner ◽  
Todd W. Thorslund
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Mortality Rate ◽  
Constant Temperature ◽  
Specific Growth ◽  
Temperature Fluctuations ◽  
Mortality Rates ◽  
Salmo Gairdneri ◽  
Lethal Temperature ◽  
Specific Mortality

Specific growth and mortality rates of juvenile rainbow trout (Salmo gairdneri) were determined for 50 days at seven constant temperatures between 8 and 22 °C and six diel temperature fluctuations (sine curve of amplitude ±3.8 deg C about mean temperatures from 12 to 22 °C). For constant temperature treatments the maximum specific growth rate of trout fed excess rations was 5.12%/day at 17.2 °C. An average specific mortality rate of 0.35%/day was observed at the optimum temperature and lower. At temperatures in excess of the growth optimum, mortality rates were significantly higher during the first 20 days of this experiment than the last 30 days. The highest constant temperature at which specific growth and mortality rates became equal (initial biomass remained constant over 40 days) was 23 °C. The upper incipient lethal temperature was 25.6 °C for trout acclimated to 16 °C. A yield model was developed to describe the effects of temperature on the living biomass over time and to facilitate comparison of treatment responses. When yield was plotted against mean temperature, the curve of response to fluctuating temperatures was shifted horizontally an average 1.5 deg C towards colder temperatures than the curve of response to constant temperature treatments. This response pattern to fluctuating treatments indicates that rainbow trout do not respond to mean temperature, but they acclimate to some value between the mean and maximum daily temperatures. These data are discussed in relation to establishment of criteria for summer maximum temperatures for fish. Key words: constant temperature, fluctuating temperature, specific growth rate, specific mortality rate, yield, lethal temperature, zero net biomass, rainbow trout, thermal criteria

Growth dynamics of mosaic muscle fibres in fingerling rainbow trout (Salmo gairdneri) in relation to somatic growth rate

1980 ◽  
Vol 58 (9) ◽  
pp. 1535-1541 ◽  
Author(s):  
A. H. Weatherley ◽  
H. S. Gill ◽  
S. C. Rogers
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Fibre Diameter ◽  
Fork Length ◽  
Salmo Gairdneri ◽  
Muscle Fibres ◽  
Experimental Conditions ◽  
Cross Sectional ◽  
Rate Condition ◽  
Epaxial Muscle

We examined the effects of varying water temperature (5, 12, 20 °C), ration size (ad libitum, and 3–4% of dry body weight per day), and injection of bovine growth hormone, on the growth characteristics of the epaxial muscle in laboratory-reared rainbow trout. Although the experimental conditions resulted in differences in growth rate, condition factor (K = W/L3 × 102) and dry weight, we found that, below a fork length of 18–20 cm, an increase in the cross-sectional area of the epaxial muscle occurs mainly by the addition of new fibres. However, between 20 and 25 cm the increase evidently results mainly from an increase in diameter of existing fibres. The relationship between fibre diameter frequency and fork length is characterized, and the implications of this relationship in limiting growth of this species is discussed.

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