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DIETARY MANIPULATION OF FATTY ACID BIOSYNTHESIS AND METABOLISM TO IMPROVE FISH PERFORMANCE AND FILLET CONTENT WITH AN EMPHASIS ON OMEGA-3 LC-PUFA AND ARACHIDONIC ACID WHEN FEEDING HIGH PLANT OIL FEEDS
No full textFish oils have been used as the primary source of dietary lipid in aquafeeds, especially for salmonids and marine species, which require the supply of long-chain polyunsaturated fatty acids (LC-PUFA) such as eicosapentaenoic acid (20:5n-3, EPA), docosahexaenoic acid (22:6n-3, DHA) and arachidonic acid (20:5n-6, ARA), considered essential fatty acids for many species. However, fish oils have been in increasingly higher demand in the aquaculture industry, while fixed or diminishing supplies have resulted in higher prices, creating the need for alternative oils. In recent decades, extensive research has been conducted to find alternative, sustainable lipid sources for aquafeeds. Plant-derived oils such as soybean, canola, and linseed oil have been widely used and studied in the aquaculture field because they are reasonably cost-effective and readily available. However, the increasing use of such oils has resulted in the decline of beneficial omega-3 fatty acids in the fish fillet, thereby reducing the nutritional value to the final consumer. This thesis aims to investigate fatty acid metabolism by supplementing cholesterol, which plays a vital role in stimulating fatty acid β-oxidation and the conversion of α-linolenic acid (ALA) to DHA, to plant oils (soybean and linseed oils) widely used in aquafeed. Furthermore, this thesis includes an investigation of a novel lipid source to replace fish oil in the trout diet and to better understand fatty acid metabolism in an effort to increase beneficial omega-3 fatty acids in the fish fillet through metabolic processes. Following these studies, experiments were conducted to examine the effects of ARA, known as an essential fatty acid in some marine carnivorous species, on fatty acid metabolism, growth performance, health, and inflammatory responses of different size classes of trout. The first study demonstrated that fish fed 100% of linseed oil with cholesterol supplementation had significantly higher weight gain and feed intake compared to other plant-based diets. In addition, cholesterol supplementation numerically increased EPA and DHA levels in fish fillet when linseed oil was provided above 50%. The second study was conducted over a complete production cycle to evaluate a new transgenic canola oil (LatitudeTM oil; Cargill) high in EPA, DPA and, DHA compared with conventional canola oil as a substitute for fish oil in rainbow trout feeds. The results of that study demonstrated that LatitudeTM oil improves fish growth and yields elevated n-3 long-chain polyunsaturated fatty acid content in the fillet, making it a candidate lipid source for use in rainbow trout feeds. However, both intestinal inflammation and size and number of absorptive vacuoles showed significant differences among diet with the distal intestine of fish fed 100% LatitudeTM oil having a reduction in size and number of absorptive vacuoles and signs of inflammation. The last two studies, evaluating the effect of ARA in two different stages, swim-up and sub-adult, demonstrated that dietary ARA neither negatively nor positively affected growth performance during both stages. However, dietary ARA improved the immune and inflammatory response to hypoxia and high temperature by enhancing the activation of antioxidant pathways and inhibiting pro-inflammatory responses.doctoral, Ph.D., Natural Resources -- University of Idaho - College of Graduate Studies, 2022-1
Skin Friction Measurement on a Flexible Membrane Using Oil Film Interferometry
No full textFluid-structure-interactions (FSI) has applications in diverse areas and has been a research focus for several decades. FSI is used in studying aerodynamics and can be observed from a flag flapping in the wind, or a parachute deploying. The nonlinear coupling between a structure and fluid flow makes computational and theoretical studies challenging. One of the critical fluid dynamic parameters of FSI research is skin-friction coefficient (Cf ), a dimensionless parameter used to determine viscous drag on a structure. An accurate estimation of Cf can provide critical information regarding FSI physics and aid in developing robust computational and theoretical models. Furthermore, traditional experimental approaches to measure Cf are intrusive and can alter the fluid flow field and structure properties. One such traditional method being a Stanton tube, where the tube is placed close to the structure surface to collect pressure differences, in turn obstructing the flow near the structure. Another method being a Micro Electrical Mechanical System (MEMS) sensor, a reliable method that requires contact with the surface, influencing the behavior of the structure. This study aims to design and develop an optical-based Cf measurement technique (i.e., Oil-Film-Interferometry (OFI)) that is non-intrusive and can be used to estimate values on a very flexible and transparent membrane. For this purpose, an in-house OFI system was designed by creating a 3-D printed model that negates pressure gradients at the leading edge of a flat plate. The OFI system was used to perform experiments on a flat plate model in the wind tunnel facility at the University of Idaho’s Experimental Fluids and Aerodynamics Laboratory (EFAL). In-plane image analysis of oil fringe patterns were achieved by process of photogrammetry, which mapped a 3-D space to a 2-D image plane. After image correction, a Windowed Fourier Transform (WFT) approach was used to analyze fringe spacing that led to determination of the local oil height that is used to iteratively solve for Cf . The OFI technique successfully measured Cf on a flat plate model and yielded a deviation within 6% from theoretical results. After a successful demonstration in the wind tunnel, the in-house OFI system was designed to measure skin friction on a flexible membrane model using the open jet facility in EFAL. The OFI results on the flexible membrane yielded a deviation within 8% of theoretical Cf results over a flat plate. This study successfully demonstrated the application of the OFI technique to measure Cf on flexible transparent structures. Performing OFI to measure the skin friction coefficient on a flexible membrane has provided a new approach to accurately characterize wall shear stresses on a flexible structure, setting the foundation for future work in which OFI measurements will be taken on a flexible membrane with various modes of oscillation.masters, M.S., Mechanical Engineering -- University of Idaho - College of Graduate Studies, 2022-0
The Effect of Impurities and Geometry on the Corrosion and Thermodynamic Behavior of Molten Salts
No full textMolten salt systems are highly relevant to the energy industry and have become a focus of much research in recent years, particularly in nuclear energy and thermal energy storage. Many types of molten salt are used for various systems, including fluoride, chloride, and nitrate salts. These types of salts have thermodynamic and chemical properties, which make them advantageous to energy production systems. Molten salt systems are superior to other systems in many ways, including design simplification, atmospheric operating pressures, higher heat capacities, safer operational parameters, and the possibility for on-line salt processing. Despite the advantages of a molten salt system, these concepts can also contain more complexity than many other energy storage systems due to the chemistry of the salt mixtures. In particular, molten salt systems can be particularly susceptible to corrosion. A risk assessment was performed as part of this dissertation, determining that corrosion risk is of particular concern in designing a molten salt system. To address the risk of corrosion in molten salt system design, two phases of research were conducted, which are described in this work. The first phase aimed to determine the effect of corrosion on the thermodynamic behavior of molten salt. In particular, the melting behavior of two types of molten salt was investigated, with additions of impurities that could result from corrosion. The second phase of research aimed to determine the effect of system design on molten salt corrosion. By use of COMSOL multiphysics, four different basic geometries were modeled, which were representative of geometries that could be found in a large-scale system. Molten salt laminar flow was modeled in these geometries, with corrosion behavior coupled to the laminar flow physics. This model was first of its nature and thus was simple in form. It provided information on the general impact of design changes on the velocity profile and corrosion behavior in representative geometries. The combination of experimentation and modeling determined that design changes can be made to reduce the impact of corrosion on a molten salt system. Extending the system temperature to above the entire melting range of a molten salt will ensure an operating fluid that is entirely liquid in phase. Modifying geometry to reduce areas of peak velocity will reduce the intensity of local corrosion, and reducing the overall system velocity will also reduce corrosion. Incorporating system design changes such as these in preliminary phases of design can reduce overall corrosion risk, extending the lifetime of the system.doctoral, Ph.D., Nuclear Engr & Industrial Mgmt -- University of Idaho - College of Graduate Studies, 2022-0
Novel Methods for Deriving Snow Data from Remote Cameras and Applications to Wildlife Habitat and Ungulate Management
No full textSnow, in both its quantity and its dynamics, is a key driver of many geophysical and ecological processes and is well understood from a purely hydrologic perspective. However, snow as it affects wildlife habitat and survival is only understood very broadly despite its potential effects on thermoregulation, movement, foraging, and escape from predation over winter. This knowledge gap can largely be attributed to the lack of snow data at temporal and spatial scales meaningful to wildlife. Remote cameras are already widely used in wildlife research and potentially are a low-cost, low-maintenance option for collecting snow data at high spatial and temporal resolutions in complex forested terrain. My thesis explores how remote cameras can be used to collect snow and weather data and then applies these data to two wildlife habitat questions. I begin by asking what hydrometeorological data can be derived from remote camera images. Chapter 1A focuses on snow depth and a package I built in program R to measure snow depth without the use of permanent snow stakes deployed in the camera viewshed. The potential use of this code in distance sampling with remote cameras is heavily emphasized because it may be of interest to other users of the package. However, for this thesis, no distance sampling was performed; the code was only implemented in creating virtual snow stakes which could be used to measure snow depth in the camera images for Chapters 2 and 3. This R package provides a means for other camera studies to collect fine-scale snow depth data without potentially impacting wildlife behavior. Chapter 1B focuses on correcting air temperature measurements made by cameras and deriving precipitation phase from combined image data and temperature data. The temperature correction model gives researchers more confidence in the temperature measurements collected by their cameras. However, precipitation phase is complicated to discern because of the relatively low resolution of images and the effects of wind and canopy interception. My other two chapters use these methods and models to address two wildlife habitat questions. One, what biophysical conditions promote retention of snow in complex forested terrain? Using snow and temperature data derived from the remote cameras and biophysical data collected at the camera sites, I built a model predicting locations of snow refugia in complex forested terrains. Knowledge about late-season snow cover provides insight into how forests can be managed to promote snow retention and thus promote habitat for snow-dependent wildlife species. Two, how do snow characteristics and winter severity affect the movement and distribution of ungulates over winter? I built a model relating deer and elk detections at my cameras to snow depth and temperature from cameras and snow density and hardness from on-site measurements. Snow density and hardness are expected to change drastically to the possible detriment of ungulates, but these properties are not included in current winter severity indices; My model is the first attempt at including these snow properties to better define winter severity for ungulates in a changing climate.masters, M.S., Fish & Wildlife Sciences -- University of Idaho - College of Graduate Studies, 2022-1
Arbor Notes December 2022
No full textThis December publication includes the subject headings: Message from the President; Lego Build of the University of Idaho arboretum Wins Second Place at the Latah County Fair; Where are They Now?; UI Arboretum Associates Donor Roll; Calendar of Upcoming events; Then and Now; UI Arboretum Plant Sale; Paper Making at The Arboretum; UI Arboretum Associates Gather After Two-Year Hiatus; UI Arboretum Employees; 'Silence is an illusion...' and other musical wonders; Report from the Horticulturist
An Empirical Analysis of the Price Variance of Agricultural Commodities before and after COVID-19 in the USA
No full textUsing monthly price data of beef, pork, broilers, apples, strawberries, potatoes and tomatoes we compare and contrast price volatility before and after COVID-19 pandemic. We also compare and contrast the price volatility among meat, fruits and vegetables before and after COVID-19. Our analysis shows how COVID-19 induced disruptions affected these commodities’ price. Our empirical results suggest that COVID-19 has a significantly positive impact on increasing prices of beef, pork and strawberries. On the other hand, COVID-19 has a negative impact on potatoes prices. COVID-19 has no significant effects on broilers, apples and tomatoes prices. Gasoline prices and all three kind of meat prices have a positive relationship.masters, M.S., Agricultural Economics & Rural Soc -- University of Idaho - College of Graduate Studies, 2022-1
Two-way Plant-mediated Interactions Between a Plant Parasitic Nematode and a Foliar Herbivore Arthropod
No full textInteractions between belowground and aboveground heterotrophic communities that have no direct physical contact can be connected through the plant as the mediator of these interactions. Herbivores use different types of cues to find suitable host plants, and plants respond to herbivore attack by producing a suite of defensive compounds that can affect the choice and performance of herbivores. The aim of this study was to explore two-way, plant- mediated interactions between two herbivores: the belowground plant-parasitic root knot nematode (RKN) Meloidogyne incognita (Tylenchida: Heteroderidae), and the two-spotted spider mite, Tetranychus urticae Koch (TSSM) (Acari: Tetranychidae), which is an aboveground folivore. Two different host species were used, Lima bean (LB) (Phaseolus lunatus cv. Henderson), which is an optimal host for TSSM, and tomato (Solanum lycopersicum cv. Rutgers), which is a sub-optimal host for TSSM, but optimal for RKN.For the belowground experiments, to test RKN preference, we used two-way glass olfactometers to determine the response of RKN to a LB plant exposed to TSSM versus a LB plant that was not exposed to TSSM. RKN penetrated the roots of non-exposed plants at a greater rate than the TSSM exposed plants. For the aboveground experiments, we used leaf discs and two-way olfactometers to conduct choice tests of the response by TSSM to an RKN-infected plant at 1, 2 and 25 days post-inoculation (DPI) with RKN against a plant of the same age that had not been exposed to RKN. More TSSM were found on non-infected LB plants compared to RKN-infected plants but only at 25 DPI. On tomato plants, TSSM significantly preferred RKN infected plants at 1 DPI. We also tested the effect of the inoculation on the rhizosphere of tomato plants (1 DPI) of the soil-dwelling entomopathogenic nematode (EPN) Steinernema carpocapsae (Rhabditida: Steinernematidae) and found that TSSM preferred the EPN inoculated plants compared to non-inoculated tomato. We carried out a no-choice performance test for TSSM on both LB and tomato plants to determine the performance of the TSSM on plants inoculated with RKN versus clean plants. There was no observed effect of RKN exposure on TSSM performance. This thesis research shows that plants can mediate interactions between below and aboveground herbivores that share the same plant.masters, M.S., Entomology, Plant Path & Nematology -- University of Idaho - College of Graduate Studies, 2022-1