Thesis (Ph. D.)--Oregon State University, 1996. / Typescript (photocopy). Includes bibliographical references. Also available online.

Thesis (MS) University of Montana, 2008. / Title from author supplied metadata. Contents viewed on May 19, 2010. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 42-47). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 121-131). Also available on the World Wide Web.

Ph.D. (Zoology) / The contribution of genetics in animal husbandry and agriculture has long been recognised. The application of genetics in fish culture has not yet become established because both overseas and locally the focus was until recently still on culture techniques. In South Africa the only genetic data on the rainbow trout (Parasalmo mykiss) stock is limited to one electrophoretic survey (Op't Hoff et al. 1982). During 1982 to 1985 a survey was done of trout angling management in provincial trout angling waters by the Transvaal Division of Nature Conservation. The goal was to find and eliminate inhibiting factors affecting trout angling in order to provide a better service. Angling results were improved and management of trout waters brought into line with its own potential. The percentage returns of trout caught however, seemed to reach a level that could only be breached by genetically improving the trout strains used for stocking. The inherent inability of inbred domesticated P. mykiss strains to grow and survive in nature has been shown to affect its survival when stocked in streams and dams for angling purposes (Kincaid 1981; Ersbak & Haase 1983).

This thesis examined the function of the urinary bladder in vivo in the freshwater rainbow trout. In the first part of the study two new techniques were developed to examine the possible urine storage and ionoregulatory roles of the bladder in vivo. An indirect approach, using non-catheterized fish, involved "spot sampling" from the bladder to determine urine composition, and measurement of the appearance of ^3H polyethylene glycol-4000 (a glomerular filtration marker) in surrounding water to quantify urination events. The direct approach employed a new external catheterization technique to collect naturally discharged urine. Both methods demonstrated that resting trout urinate in intermittent bursts at 20-30 min intervals, and that natural urine flow rate (U.F.R.) is at least 20 % lower and urinary Na^+ and Cl^- excretion rates at least 40% lower than determined by the traditional internal bladder catheter technique. The urine is stored for approximately 25 min prior to discharge, and significant reabsorption of water and ions (Na^+, Cl^-, K^+, urea, and possibly other substances) occurs via the bladder epithelium during this period; a small residual volume is likely always maintained. The second part of the study employed the new external catheter and the traditional internal catheter to quantify the responses of the bladder, relative to those of the kidney, to two experimental disturbances. Chronic (32 h) infusion with 140 mM NaCl produced isosmotic volume loading without a change in plasma [Na^+], [Cl^-], or acid-base status. The kidney responded with a large increase in glomerular filtration rate (G.F.R.), a smaller increase in U.F.R., and increased reabsorption of water and ions. The bladder responded with a small increase in urination burst volume, a larger increase in burst frequency, and therefore a decreased urine storage time. Despite this increased throughput, Na^+ and Cl^- reabsorption rates across the bladder epithelium actually increased. Reabsorption of urea and K^+ remained constant, despite expected decreases due to decreased urine storage time. A similar infusion with 140 mM NaHCO_3 produced isosmotic volume loading together with metabolic alkalosis reflected m increased blood pH, increased plasma [HCO_3^-], decreased plasma [Cl^-], with no change in plasma [Na^+]. The response of the kidney was similar, though HCO_3^- filtration, reabsorption, and excretion rates all increased, while rates for Cl^- were proportionately lowered; renal Na^+ handling was unaffected. Bladder urination patterns and Na^+ reabsorption were also similar, but there was no evidence of bladder involvement in HCO_3^- secretion or reabsorption (ie. in acid-base regulation). It is concluded that previous studies using internal catheterization have greatly underestimated the ionoregulatory effectiveness of the entire renal system by negating bladder function. The external catheterization technique developed in this thesis provides researchers with a method to collect naturally vented urine, and thereby evaluate the role of the entire renal system, including the bladder, in response to experimental manipulations. / Thesis / Master of Science (MS)

Three studies were conducted to evaluate the relationship between insulin and nutritional parameters in rainbow trout. In the first study effects on growth parameters and tissue composition of rainbow trout were investigated following injection of bovine insulin at two dose levels every 48 hr for 56 days. In addition, [¹⁴C]-leucine incorporation into plasma, liver, and skeletal muscle was studied for the two insulin treatments and a group of the saline-injected controls given a single shock-dose of insulin (5.0 IU/kg). Hypoglycemic responses were observed with all insulin treatments. In comparison to controls, high insulin treatment gave a significant body weight increase. At both levels, insulin increased the content of protein, lipid, and also the incorporation of [¹⁴C]-leucine activity in skeletal muscle. Simultaneous decreases in specific activity of plasma and liver tissue indicated a net movement of [¹⁴C]-leucine toward the peripheral musculature. No effect of the hormone was seen on the glycogen content of liver or muscle tissue over the 56-day period. In a second study, the effect of bovine insulin on tissue incorporation of [¹⁴C]-glucose and [³H]-leucine was investigated in fed and fasted rainbow trout reared on a control and high-protein diet. Insulin produced marked hypoglycemia and mobilization of liver glycogen in all treatments. Although insulin gave no evidence of glycogenic stimulation it did appear to promote oxidative clearance of [¹⁴C]-glucose. Compared to [¹⁴C]-glucose much greater tissue incorporation of [³H]-leucine was observed in fasted fish; insulin stimulated the incorporation of [³H]-leucine into skeletal muscle protein. In plasma, liver, and skeletal muscle of all treatments, the summed specific activities of [³H]-leucine was considerably greater than that of the summed values of [¹⁴C]-glucose following insulin administration. Four weeks of fasting apparently lowered basal metabolism but no changes were observed in plasma glucose and glycogen stores. There was some evidence of gluconeogenic activity in the high protein-fasted fish and the data indicated in all fasted treatments a stimulation of [¹⁴C]-glucose and [³H]-leucine metabolism following insulin administration. As a third investigation, [¹²⁵I]-iodoinsulin binding studies in the presence of a concentration range of bovine insulin were conducted to establish specific insulin binding levels in erythrocytes, skeletal muscle plasma membranes and isolated hepatocytes of rainbow trout reared on control-, high-protein and high-carbohydrate diets. Negative cooperativity was observed and receptor concentrations and apparent dissociation constants established for each preparation. No differences of specific binding attributed to diet were detected in either erythrocytes or skeletal muscle plasma membrane preparations, However, the receptor concentration of isolated hepatocytes from high-carbohydrate reared trout was increased. This contrasted to comparable mammalian studies. In view of an apparent depression of receptor concentration in skeletal muscle plasma membranes and isolated hepatocytes of high-protein reared trout, these data were interpreted according to the reciprocal relationship observed between endogenous insulin and insulin receptor concentrations established for mammals. Unlike mammals where glucose was shown to be the primary insulin secretagogue, endogenous insulin levels in rainbow trout have been closely correlated to circulatory amino acids and are thought to be primarily controlled by these protein metabolites. / Graduation date: 1982

Several compounds have been shown to induce the mixed function oxidase enzyme system of animals, and also to inhibit tumor formation. Included in this category are several vegetables and isolated vegetable components from the Cruciferae family. In this study rainbow trout were fed blanched freeze-dried cauliflower, broccoli, or Brussel sprouts at the 20% supplemental level for two months, or 500 ppm benzyl or phenethyl isothiocyanate. At this time the livers were removed and hepatic microsomal enzymes were studied. This treatment did not cause any increases in the metabolism of p-nitroanisole or benzo(a)pyrene and cytochrome P-450 levels were not elevated. On the contrary, benzo(a)pyrene monooxygenase, 7-ethoxycoumarin 0-dealkylase, resorufin 0-dealkylase, p-nitroanisole 0-demethylase, and cytochrome P-450 levels were increased in trout treated orally and intraperitoneally with β-napthoflavone. For all parameters studied, a greater increase in activity was seen in the trout treated intraperitoneally. The vegetable and isothiocyanate supplemented diets also did not inhibit tumor formation in trout challenged with 20 ppb aflatoxin B₁ for one month. A study with rats showed that both blanched freeze-dried cauliflower and air-dried cauliflower cause significant increases in p-nitroanisole 0-demethylase activity and benzo(a)pyrene monooxygenase activity and increased cytochrome P-450 levels in rat hepatic microsomes when fed at the 20% supplemental level for 25 days. It was concluded that the null effects seen with the trout fed the vegetables and isothiocyanates were not due to the heat treatment of the vegetables since rats fed blanched freeze-dried cauliflower had significant increases in enzymatic activity and increased cytochrome P-450 levels over controls. The results of the β-napthoflavone experiment verified the validity and reliability of the experimental assays and conditions and showed that trout hepatic microsomal enzymes can be induced by orally administered compounds. / Graduation date: 1981

A dietary level of Aroclor 1254 (100 ppm) was fed to rainbow trout (Salmo gairdneri) for 15 weeks to determine the effects on hepatic microsomal enzyme induction. Fish were also fed combined polychlorinated biphenyl (PCB) (100 ppm) and cyclopropene fatty acids (CPFA) (50 ppm) to determine the effects on mixed function oxidase (MFO) induction. Dietary PCBs markedly induced the microsomal activities of 7-ethoxyresorufin O-deethylase, 7-ethoxy-coumarin O-deethylase, and benzo(a)-pyrene monooxygenase. Ethoxyresorufin O-deethylase activity continued to increase to a level 77-fold higher than control at week 15. Ethoxycoumarin O-deethylase and benzo(a)-pyrene monooxygenase activities increased to 7.1-fold and 48-fold over control at week 9 and then slightly decreased to 6.8-fold and 45-fold over control at week 15, respectively. Cytochrome P450 values remained approximately 2-fold above controls from week 5 through week 15. At weeks 1 and 3, cytochrome P450 levels were not significantly different from control. Ethoxyresorufin O-deethylase, ethoxycoumarin O-deethylase, and benzo(a)pyrene monooxygenase activities in the combined PCB and CPFA-fed trout were significantly higher than in controls and CPFA-fed fish, and significantly lower than in PCB-fed fish. There was no significant difference in cytochrome P450 levels after week 5. This is the first time dietary PCBs have been shown to induce the MFC system in PCB-fed rainbow trout. / Graduation date: 1980

No description available.