The influence of a diet containing salmon flesh and its oil on plasma lipids, cholesterol absorption, as well as fecal neutral and acidic steroid excretion was studied. Two female and four male normolipidemic subjects were fed diets containing approximately 40% of their caloric intake from salmon oil, polyunsaturated vegetable oil or saturated fat. Each diet was fed for four weeks. Venous blood was drawn twice weekly for the determination of plasma cholesterol and triglycerides. C¹⁴ cholesterol was administered during the last week of each dietary period to determine the absorption of dietary cholesterol. Fecal neutral and acidic steroids were determined in feces collected following the administration of the isotope. Compared to the saturated fat diet, plasma cholesterol was significantly lower following the salmon and linoleic acid diets. The salmon diet produced significantly lower plasma triglycerides than the polyunsaturated vegetable oil and saturated fat diets. The absorption of cholesterol and the fecal excretion of neutral and acidic steroids were not significantly altered by diet. / Graduation date: 1981

Thesis (M.S.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed Sept. 9, 2008. Includes bibliographical references (p. 49-58).

[No abstract available] / Science, Faculty of / Chemistry, Department of / Graduate

[No abstract available] / Science, Faculty of / Zoology, Department of / Graduate

A histological study of the eyes of juvenile sockeye, coho, pink and chum salmon in fresh water shows that the cones, external nuclear and plexiform layers of the embryos and alevins are poorly differentiated and do not attain normal histological or physiological proportions until the emergence of fry from the gravel. From a histo-physiological study it is evident that only the emerged fry and older stages are capable of retinomotor responses and that these become more marked with age. Differences in rates of adaptation are found among the species and stages. Generally, the pigment layer shows a latent period before contraction in dark. Sensitivity to light is independent of the complete light-adaptation of the retinal pigment or visual cells, while full acuity of vision is dependent upon the complete light-adaptation of cones. Threshold values of cones and rods are indicated by the feeding and schooling responses. At light intensities between the cone and rod thresholds the thicknesses of pigment and cone layers obey the Weber-Fechner Law. There is no diurnal rhythm in the positions of retinal pigment and cones of juvenile Oncorhynchus either under constant light or dark. Results are discussed in relation to the migratory, schooling and feeding behaviour. The rapid downstream migration of juvenile salmon during a relatively short period in the night may be related to a semi-dark-adapted state of the eye. / Science, Faculty of / Zoology, Department of / Graduate

The responses of chum and pink salmon fry, and coho salmon fry and smolts (Oncorhynchus keta, O. gorbuscha, and O. kisutch) to isotonic and hypertonic seawater were studied in sharp-gradient tanks to determine whether or not salinity gradients can act as directive agencies in the seaward migration of juvenile Pacific salmon. Chum and pink fry responded positively to both concentrations of seawater. Coho fry responded positively to isotonic seawater but did not respond positively to hypertonic seawater. Coho smolts responded positively to hypertonic seawater. Acclimation of chum fry to seawater prior to observation of their responses resulted in a reduction of their initial response although there was no significant change in the levels of response finally obtained. Major differences in the concentration of the acclimatory solutions did not affect the responses of this species to hypertonic seawater. The activity of chum and pink fry, and of coho smolts generally decreased on first entry into seawater. Observations on acclimated chum fry suggest that activity is related to osmotic control. Decreased activity may arise from the interaction of absorbed electrolytes on muscle protein. This effect continues until the commencement of osmoregulation when excess absorbed ions are removed from the muscles. The relatively high levels of activity observed in pink fry may be the result of hyperfunction of the thyroid gland, a condition related to osmotic stress in fresh water. The influence of sea water on the seaward movements of juvenile Pacific salmon is probably two-fold. The effects of absorbed electrolytes on motor activity may decrease the intensity of rheotrophic responses which would tend to keep the migrants in river mouths, while at the same time increasing the probability of passive displacement out to sea by current action. Active positive responses to salinity gradients enhance the likelihood of movement into the ocean. Control experiments indicated the operation of some factor or factors resulting in preference reactions by chum and pink fry and coho smolts for the tanks in which they had been originally placed. The possible influence of olfactory and visual cues on this preference reaction has been discussed. / Science, Faculty of / Zoology, Department of / Graduate

Tie conditions in a geologically youthful area are outlined, and also the chemical and biological conditions in Bear Lake of the Skeena watershed. The life history of the sockeye, Qncorhynchus nerka, in this area is outlined as closely as information permits. The spawning of the sockeye where stream conditions are generally unfavourable and the probability of lake spawning in the deeper waters is discussed. The contribution of this area in relation to the whole Skeen sockeye run is estimated. / Science, Faculty of / Zoology, Department of / Graduate

The problem of the serological relationships of some members of the genera Oncorhynchus, Salmo and Salvelinus was investigated. Serum samples were obtained from the five species of Pacific salmon, (genus Oncorhynchus), the rainbow trout (Salmo gairdnerii gairdnerii Richardson) and the dolly varden char (Salvelinus alpinus malma Walbeum). The protein content of all sera was determined. The antisera were produced in rabbits by the short series injection method, the initial dosage being 5 mgms. of serum protein per kilogram of body weight. Relationships were determined by means of the precipitin reaction using the ring test technique. Relationship values were expressed as percentages of the homologous titer. In all, eight sera were tested against six antisera. The results showed that the coho, spring, sockeye and kokanee salmon form a closely related group and cannot be separated serologically by means of the ring test. The chum salmon demonstrated a significant difference from this latter group, as did also the rainbow trout and the dolly varden, the dolly varden exhibiting the greatest difference. The tests with the pink salmon antiserum gave indications that this species is as equally distant from the chum salmon as it is from the coho, spring, sockeye and kokanee salmon. Reactions of the same intensity as the above were obtained with the rainbow trout serum. This may have been due to contamination of the antigen. Control tests were carried out using the serum of the lingcod (Ophiodon elongatus Girard). This gave very weak reactions with the antisera of the pink and kokanee salmon as well as the dolly varden char. / Science, Faculty of / Zoology, Department of / Graduate

Chum salmon migrants (Oncorhynchus keta) treated with thyroxine and testosterone show a less intense schooling reaction than the control or thiourea treated fish. Coho salmon fry (O. kisutch) subjected to the same treatments showed that thiourea produced an increase in aggregation while the grouping of fish from the other two treatments was similar to that of the control cohos. It was also found that thyroxine treated and control chums subject to gradients of light intensity move toward the areas of greater intensity. The thiourea treated chums and the cohos from all treatments moved toward the lower light intensity. In another series of experiments it was established that chum migrants and coho fry regularly move into the faster of two parallel streams of water. The coho, however, soon commence nipping and become indifferent to the faster flow. / Science, Faculty of / Zoology, Department of / Graduate

The seasonal and diurnal movements of sockeye, pink and coho salmon fry are described. For sockeye, at least, the time of the seasonal migration froa the spawning area is related to the temperature "budget" during their period of development in the gravel. Their seasonal migration occurs earlier following an incubatory period in which above average temperature prevailed and later following relatively low temperatures. Emergence from the gravel appears to occur normally only after a certain stage of development is reached. The diurnal movements of all three species are precisely regulated by their response to light. The strong negative phototaxis exhibited by the fry at this time restricts their movement solely to the hours of darkness. The downstream movement of sockeye and coho and also apparently of pink fry is initiated within a three hour period following darkness. The presence of artificial light almost completely prevents this movement either throughout the night or until such time as the light is removed. The data indicate that a period of night blindness occurs which is common to the three species and that their downstream movement is initially a result of a displacement by the current. Once entered into the stream the migration continues until evacuation of the stream is complete or until daylight approaches. The response of sockeye fry to current during this continued movement appears predominantly positive in fast currents and negative in relatively slew currents. The migration is considered to result from both a displacement by the current and a movement directed on the part of the fry. / Science, Faculty of / Zoology, Department of / Graduate