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• 11. [Article] The parr-smolt metamorphosis in steelhead trout as affected by photoperiod and temperature

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  Citation × Citation Citation Abstract Copy Title: The parr-smolt metamorphosis in steelhead trout as affected by photoperiod and temperature Author: Wagner, Harry Henry See pdf Title: The parr-smolt metamorphosis in steelhead trout as affected by photoperiod and temperature Author: Wagner, Harry Henry See pdf Close

• 12. [Article] An investigation of the blood-brain barrier in the rainbow trout (Salmo gairdneri)

  Citation × Citation Citation Abstract Copy Title: An investigation of the blood-brain barrier in the rainbow trout (Salmo gairdneri) Author: Klika, Larry John Title: An investigation of the blood-brain barrier in the rainbow trout (Salmo gairdneri) Author: Klika, Larry John Close

• 13. [Article] Acute toxicity and carcinogenic activity of ochratoxin in rainbow trout (Salmo gairdneri)

  Citation × Citation Citation Abstract Copy Title: Acute toxicity and carcinogenic activity of ochratoxin in rainbow trout (Salmo gairdneri) Author: Doster, Robert Charles Title: Acute toxicity and carcinogenic activity of ochratoxin in rainbow trout (Salmo gairdneri) Author: Doster, Robert Charles Close

• 14. [Article] Exercise and acid-base balance in rainbow trout

  Citation × Citation Citation Abstract Copy Title: Exercise and acid-base balance in rainbow trout Author: Meyerhoff, Roger Dean Title: Exercise and acid-base balance in rainbow trout Author: Meyerhoff, Roger Dean Close

• 15. [Article] Genetic comparison of Deschutes River steelhead and rainbow trout at selected enzyme loci

  Citation × Citation Citation Abstract Copy Title: Genetic comparison of Deschutes River steelhead and rainbow trout at selected enzyme loci Author: Chilcote, Mark W. Title: Genetic comparison of Deschutes River steelhead and rainbow trout at selected enzyme loci Author: Chilcote, Mark W. Close

• 16. [Article] Mechanisms of accessory cell function in rainbow trout (Oncorhynchus mykiss)

  Citation × Citation Citation Abstract Copy Title: Mechanisms of accessory cell function in rainbow trout (Oncorhynchus mykiss) Author: Ortega, Henry William Title: Mechanisms of accessory cell function in rainbow trout (Oncorhynchus mykiss) Author: Ortega, Henry William Close

• 17. [Article] Some enzyme changes in levers of rainbow trout (Salmo gairdnerii) fed aflatoxin B₁ and sterculic acid

  Citation × Citation Citation Abstract Copy Title: Some enzyme changes in levers of rainbow trout (Salmo gairdnerii) fed aflatoxin B₁ and sterculic acid Author: Taylor, Stephen Lloyd Title: Some enzyme changes in levers of rainbow trout (Salmo gairdnerii) fed aflatoxin B₁ and sterculic acid Author: Taylor, Stephen Lloyd Close

• 18. [Article] A partial characterization of high and low molecular weight immunoglobulin in rainbow trout (Salmo gairdneri)

  Citation × Citation Citation Abstract Copy Title: A partial characterization of high and low molecular weight immunoglobulin in rainbow trout (Salmo gairdneri) Author: O'Leary, Patrick John Title: A partial characterization of high and low molecular weight immunoglobulin in rainbow trout (Salmo gairdneri) Author: O'Leary, Patrick John Close

• 19. [Article] Aflatoxin mutagenesis and metabolism and their dietary modification in rainbow trout (Salmo gairdneri)

  Aflatoxin B₁ (AFB₁) is a mold-produced toxin which has been shown to be a potent hepatocarcinogen in many animal species. Of the species studied thus far, rainbow trout have proven to be the most sensitive. ...

  Citation × Citation Citation Abstract Copy Title: Aflatoxin mutagenesis and metabolism and their dietary modification in rainbow trout (Salmo gairdneri) Author: Coulombe, Roger A. Aflatoxin B₁ (AFB₁) is a mold-produced toxin which has been shown to be a potent hepatocarcinogen in many animal species. Of the species studied thus far, rainbow trout have proven to be the most sensitive. Experiments were conducted to investigate various aspects of AFB₁ metabolism in this species, including in vitro mutagenesis, and effects of dietary modifiers of AFB, carcinogenesis on in vitro metabolism and mutagenesis. A comparative study of AFB₁ metabolism in two salmonid species was also conducted. In the first study, the relative mutagenic potencies of several alfatoxin metabolites were evaluated using a trout liver fraction system. Preliminary studies characterizing trout liver fractions for use as an activation system were described. The results from comparative mutagenicity experiments demonstrated that in vitro mutagenic potencies qualitatively correlated with the in vivo carcinogenic activities of various aflatoxins in rainbow trout. The importance of these findings is discussed. In the second study fish hepatocytes were characterized to examine possible differences in activation of AFB₁ to bacterial mutagens by hepatocytes from rainbow trout and coho salmon, two species which are known to differ markedly in sensitivity to the carcinogenic effects of AFB₁. Activation efficiency was approximately three times greater in hepatocytes from trout compared to salmon. A more marked difference was seen when S20 liver fractions from the two species were used. Analysis of unbound [³H]AFB₁ metabolites revealed that trout hepatocytes metabolized [³H]AFB₁ to a greater extent than salmon. The results accurately reflected in vivo carcinogenesis trends in salmonid fish. Additional experiments were conducted to evaluate the effects of dietary modifiers of AFB₁ carcinogenesis on in vitro mutagenesis and metabolism of AFB₁. Dietary β-naphthoflavone (β-NF) was shown to induce the production of a novel trout metabolite of AFB₁, aflatoxicol M₁ (AFL-M₁). AFL-M₁ exhibited a mutagenic potency less than AFB₁ or aflatoxicol (AFL), but greater than that of aflatoxin-M₁ (AFM₁). Dietary β-NF, however, appeared to have no effect on in vitro mutagenic activation of AFB₁ using hepatocytes or liver S20 fraction from trout. Dietary PCBs (Aroclor 1254) was shown to significantly decrease in vitro mutagenesis of AFB₁, which reflected a similar PCB-mediated inhibitory effect on AFB₁ carcinogenesis in trout in vivo. Cyclopropenoid fatty acids (CPFAs) present in the diet (0-600 ppm) were shown to have no effect on in vitro mutagenesis of AFB₁, indicating CPFAs may not significantly alter in vivo initiation of AFB₁ carcinogenesis. Title: Aflatoxin mutagenesis and metabolism and their dietary modification in rainbow trout (Salmo gairdneri) Author: Coulombe, Roger A. Aflatoxin B₁ (AFB₁) is a mold-produced toxin which has been shown to be a potent hepatocarcinogen in many animal species. Of the species studied thus far, rainbow trout have proven to be the most sensitive. Experiments were conducted to investigate various aspects of AFB₁ metabolism in this species, including in vitro mutagenesis, and effects of dietary modifiers of AFB, carcinogenesis on in vitro metabolism and mutagenesis. A comparative study of AFB₁ metabolism in two salmonid species was also conducted. In the first study, the relative mutagenic potencies of several alfatoxin metabolites were evaluated using a trout liver fraction system. Preliminary studies characterizing trout liver fractions for use as an activation system were described. The results from comparative mutagenicity experiments demonstrated that in vitro mutagenic potencies qualitatively correlated with the in vivo carcinogenic activities of various aflatoxins in rainbow trout. The importance of these findings is discussed. In the second study fish hepatocytes were characterized to examine possible differences in activation of AFB₁ to bacterial mutagens by hepatocytes from rainbow trout and coho salmon, two species which are known to differ markedly in sensitivity to the carcinogenic effects of AFB₁. Activation efficiency was approximately three times greater in hepatocytes from trout compared to salmon. A more marked difference was seen when S20 liver fractions from the two species were used. Analysis of unbound [³H]AFB₁ metabolites revealed that trout hepatocytes metabolized [³H]AFB₁ to a greater extent than salmon. The results accurately reflected in vivo carcinogenesis trends in salmonid fish. Additional experiments were conducted to evaluate the effects of dietary modifiers of AFB₁ carcinogenesis on in vitro mutagenesis and metabolism of AFB₁. Dietary β-naphthoflavone (β-NF) was shown to induce the production of a novel trout metabolite of AFB₁, aflatoxicol M₁ (AFL-M₁). AFL-M₁ exhibited a mutagenic potency less than AFB₁ or aflatoxicol (AFL), but greater than that of aflatoxin-M₁ (AFM₁). Dietary β-NF, however, appeared to have no effect on in vitro mutagenic activation of AFB₁ using hepatocytes or liver S20 fraction from trout. Dietary PCBs (Aroclor 1254) was shown to significantly decrease in vitro mutagenesis of AFB₁, which reflected a similar PCB-mediated inhibitory effect on AFB₁ carcinogenesis in trout in vivo. Cyclopropenoid fatty acids (CPFAs) present in the diet (0-600 ppm) were shown to have no effect on in vitro mutagenesis of AFB₁, indicating CPFAs may not significantly alter in vivo initiation of AFB₁ carcinogenesis. Close

• 20. [Article] Effects of temperature, ration, and size on the growth of juvenile steelhead trout, Salmo gairdneri

  The effects of temperature, temperature fluctuation, and fish size on the growth of juvenile steelhead trout (Salmo gairdneri) were studied in experiments which lasted 10 to 25 days. Groups of fish were ...

  Citation × Citation Citation Abstract Copy Title: Effects of temperature, ration, and size on the growth of juvenile steelhead trout, Salmo gairdneri Author: Wurtsbaugh, Wayne Alden The effects of temperature, temperature fluctuation, and fish size on the growth of juvenile steelhead trout (Salmo gairdneri) were studied in experiments which lasted 10 to 25 days. Groups of fish were fed at ration levels varying from near-starvation to repletion. Decelerating, curvilinear relationships between rates of food consumption and growth were defined in most of the experiments. At ration levels near maintenance, temperatures elevated 3 and 6 C above the seasonal ambient temperatures decreased the growth of the trout. As feeding rate increased, the detrimental effect of temperature on growth was ameliorated. At repletion feeding levels, elevation of temperature up to approximately 17 C increased trout growth rates by increasing the maximum food consumption rates of the fish. With temperature increase from 6.9 to 22.5 C the maintenance rations of the trout increased from 2.2 to 7.4% body weight/day. Large diel temperature fluctuations of 4 and 8 C did not increase growth rates and in some cases decreased growth rates to levels below those of fish kept at constant temperatures. Increase of fish size from 0.58 to 3.36 g decreased the maintenance rations (per gram of tissue) of the trout. This decrease was attributed to decreases in metabolic rate that are associated with increases in fish size. As a consequence of this size-dependent change in metabolic rate, large fish grew faster than small fish at low ration levels. However, at ration levels greater than 9%/day, small fish grew faster than large fish. At the highest ration levels fed (9- 12%/day) gross food conversion efficiency of the large fish began to decline, while efficiencies of small fish continued to increase with increases in ration size. Periodic sampling of steelhead trout in a small coastal stream indicated that growth rates of these wild trout ranged from -0.18 to 1.6%/day. Food consumption rates of the wild trout were estimated to range from 2.0 to 7.6%/day; considerably less than the maximum consumption rates of trout kept in the laboratory. At these food consumption rates it is estimated that increases of stream temperature above the normal seasonal temperatures would decrease the growth rates of wild steelhead trout. Title: Effects of temperature, ration, and size on the growth of juvenile steelhead trout, Salmo gairdneri Author: Wurtsbaugh, Wayne Alden The effects of temperature, temperature fluctuation, and fish size on the growth of juvenile steelhead trout (Salmo gairdneri) were studied in experiments which lasted 10 to 25 days. Groups of fish were fed at ration levels varying from near-starvation to repletion. Decelerating, curvilinear relationships between rates of food consumption and growth were defined in most of the experiments. At ration levels near maintenance, temperatures elevated 3 and 6 C above the seasonal ambient temperatures decreased the growth of the trout. As feeding rate increased, the detrimental effect of temperature on growth was ameliorated. At repletion feeding levels, elevation of temperature up to approximately 17 C increased trout growth rates by increasing the maximum food consumption rates of the fish. With temperature increase from 6.9 to 22.5 C the maintenance rations of the trout increased from 2.2 to 7.4% body weight/day. Large diel temperature fluctuations of 4 and 8 C did not increase growth rates and in some cases decreased growth rates to levels below those of fish kept at constant temperatures. Increase of fish size from 0.58 to 3.36 g decreased the maintenance rations (per gram of tissue) of the trout. This decrease was attributed to decreases in metabolic rate that are associated with increases in fish size. As a consequence of this size-dependent change in metabolic rate, large fish grew faster than small fish at low ration levels. However, at ration levels greater than 9%/day, small fish grew faster than large fish. At the highest ration levels fed (9- 12%/day) gross food conversion efficiency of the large fish began to decline, while efficiencies of small fish continued to increase with increases in ration size. Periodic sampling of steelhead trout in a small coastal stream indicated that growth rates of these wild trout ranged from -0.18 to 1.6%/day. Food consumption rates of the wild trout were estimated to range from 2.0 to 7.6%/day; considerably less than the maximum consumption rates of trout kept in the laboratory. At these food consumption rates it is estimated that increases of stream temperature above the normal seasonal temperatures would decrease the growth rates of wild steelhead trout. Close