scholarly journals A BCWD-Resistant line of rainbow trout is less sensitive to cortisol implant-induced changes in IgM response as compared to a susceptible (control) line

2021 ◽  
Vol 116 ◽  
pp. 103921
Author(s):  
Fatima Quddos ◽  
Patty Zwollo
Keyword(s):  
Rainbow Trout ◽  
Control Line ◽  
Resistant Line ◽  
Susceptible Control ◽  
Induced Changes

pH-Induced Changes in Blood Lead of Lead-Exposed Rainbow Trout (Salmo gairdneri)

1978 ◽  
Vol 35 (4) ◽  
pp. 437-445 ◽  
Author(s):  
Peter V. Hodson ◽  
Beverly R. Blunt ◽  
Douglas J. Spry
Keyword(s):  
Rainbow Trout ◽  
Lead Toxicity ◽  
Blood Lead ◽  
Salmo Gairdneri ◽  
Lead Uptake ◽  
Exposure System ◽  
Test Water ◽  
Induced Changes ◽  
Inorganic Constituents ◽  
Uptake And Release

Blood of juvenile rainbow trout (Salmo gairdneri) exposed to lead in water showed increasing lead concentrations as pH of the test water decreased from 10.0 to 6.0. A decrease in pH by 1.0 unit from any reference pH resulted in an increase of blood lead by a factor of 2.1. Since sublethal lead toxicity is related to uptake, these results suggest that toxicity increases as pH decreases. Control experiments indicated that reactions of lead with inorganic constituents of the test water were complete within 3 h and that blood lead was at equilibrium with water lead within 48 h. Therefore, at the time of blood sampling in the pH experiment, both lead complexation processes in the exposure system, plus lead uptake and release from the blood, were at equilibrium. Key words: pH, lead, toxicity, fish, Salmo, blood, equilibrium.

Production benefits of breeding for worm resistance in Merino sheep

2020 ◽  
Vol 60 (13) ◽  
pp. 1643
Author(s):  
J. C. Greeff ◽  
L. J. E. Karlsson
Keyword(s):  
Mixed Model ◽  
Production Systems ◽  
Control Line ◽  
Cross Contamination ◽  
Resistant Line ◽  
Merino Sheep ◽  
Associated Production ◽  
Sheep Production ◽  
And Control ◽  
Production Losses

Context Production losses, due to worms and anthelmintic costs to control the infection, can affect the profitability of sheep production systems. Aims This study was carried out to quantify the production benefits of worm-resistant sheep. Methods Genetically worm-resistant and unselected control Merino rams were mated annually to 150 ewes in each of the Resistant and Control lines respectively over an 8-year period. All ewes and their progeny were managed in small replicated paddocks to prevent any cross-contamination between paddocks and groups. Fertility, growth, wool production, wool quality and worm resistance were measured on the ewes and their progeny. The data were analysed using mixed model methodology. Key results The progeny of the Resistant sires were on average 21–25% more worm resistant than the progeny of the Control sires. No significant differences were recorded in reproduction between mature ewes of the Resistant and Control lines, or in the survival rate of their lambs. Resistant line progeny were on average 1.6 kg heavier at weaning, received 15–17% less drenching during the experiment and produced on average 0.3 μm finer wool at hogget shearing than the Control line progeny. Conclusions It is concluded that the Resistant line coped better with a worm challenge and that this resulted in increased production. Implications This study shows that apart from improved worm resistance, there are associated production benefits in breeding for worm resistance.

Influence of Starvation on Selected Temperature of some Salmonids

1967 ◽  
Vol 24 (7) ◽  
pp. 1515-1519 ◽  
Author(s):  
M. Yaqub Javaid ◽  
John M. Anderson
Keyword(s):  
Rainbow Trout ◽  
Atlantic Salmon ◽  
Brook Trout ◽  
Starvation Period ◽  
Induced Changes

Starvation-induced changes were observed in the selected temperature of some under-yearling salmonids. In Atlantic salmon an upwards shift occurred within 24–28 hr after cessation of feeding. In brook trout and rainbow trout a downwards shift occurred within 24 hr after cessation of feeding. Brook trout showed an initial overshoot. These changes were maintained more or less constantly throughout the starvation period which lasted from 15 to 22 days. In all cases the selected temperature had returned to its pre-starvation value within 24 hr after resumption of feeding.

Turbidity-Induced Changes in Reactive Distance of Rainbow Trout

1992 ◽  
Vol 121 (4) ◽  
pp. 437-443 ◽  
Author(s):  
Jeffrey C. Barrett ◽  
Gary D. Grossman ◽  
J. Rosenfeld
Keyword(s):  
Rainbow Trout ◽  
Reactive Distance ◽  
Induced Changes
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