Interpreting Neuroendocrine Hormones, Corticosterone, and Blood Glucose to Assess the Wellbeing of Anesthetized Rats during Euthanasia

Current recommendations for assessing animal wellbeing during euthanasia suggest that measuring neuroendocrine hormones-such as ACTH, noradrenaline, and adrenaline-is preferable to measuring corticosterone and blood glucose because of the sensitivity of neuroendocrine hormones to the acute stress associated with rapid methods of euthanasia. However, theseneuroendocrine hormones can be stimulated in ways that confound interpretation of welfare assessment in euthanasia studies.Although this property does not negate the usefulness of neuroendocrine hormones as tools of assessment, it is importantto differentiate the stress associated with the induction of anesthesia before the loss of consciousness (an animal wellbeingconcern) with the physiologic responses that occur after the loss of consciousness (not an animal wellbeing concern). In thisstudy, rats were anesthetized by using a ketamine-xylazine combination. Once the rats achieved a surgical plane of anesthesia,they were exposed to O2, CO2, or isoflurane, followed by terminal blood collection to assess concentrations of ACTH,noradrenaline, corticosterone, and blood glucose. Compared with animals exposed to O2 or isoflurane, rats exposed to CO2had significant increases in their serum concentrations of ACTH and noradrenaline, but blood glucose and corticosteronedid not differ between groups. These findings indicate that noradrenaline and ACTH should be used with caution to assessanimal wellbeing when the method of euthanasia might confound that assessment

Home Cage Compared with Induction Chamber for Euthanasia of Laboratory Rats

This study compared behavioral and physiologic changes in Sprague-Dawley and Brown Norway rats that were euthanizedby using a 30% volume displacement rate of CO2 in either their home cage or an induction chamber; rats euthanized in thehome cage were hypothesized to demonstrate a higher level of animal wellbeing. No significant differences were detectedin the physiologic responses to home cage versus induction chamber euthanasia groups. A few strain-related behavioraldifferences occurred. The number of digs per second was higher in Brown Norway compared with Sprague-Dawley rats when in the home cage, where a digging substrate was present. Rearing frequency was higher in both Brown Norway and Sprague-Dawley rats in the induction chamber compared with the home cage. This study demonstrated that although strainspecific differences were associated with the process of euthanasia, there were no significant differences between the treatment groups of home cage compared with induction chamber. This finding suggests that-from the perspective of a rat-either the home cage or an induction chamber can be used for euthanasia, with likely extension of this conclusion to use of either method to the induction of anesthesia

Wellbeing of Alcohol-preferring Rats Euthanized with Carbon Dioxide at Very Low and Low Volume Displacement Rates

The 2013 AVMA Guidelines on Euthanasia recommend the use of very-low or low flow rates of 100% carbon dioxide to euthanize small rodents. Although inhalation of high concentrations of carbon dioxide are generally recognized as painful in humans, whether the use of these low-flow methods of euthanasia increase potential distress for rats is unclear. This study compared physiologic and behavioral markers of animal wellbeing for rats euthanized by using 10% volume displacement per minute (VD/min), 30% VD/min, and 70% VD/min of 100% carbon dioxide. Rats were recorded during euthanasia for subsequent behavioral scoring, and blood samples were taken after euthanasia for assessment of blood glucose and serum corticosterone levels. In this study, rats euthanized with 10% or 30% VD/min of 100% carbon dioxide demonstrated increases in various behaviors, such as rearing and standing, concurrent with increases in serum corticosterone. Rats euthanized with 70% VD/min of 100% carbon dioxide did not exhibit these changes. The results suggest that a euthanasia method of 70% VD/min of 100% carbon dioxide may minimize potential pain and distress and thus be more humane for rats, as compared with very-low- and low-flow methods of carbon dioxide euthanasia

Effects of Music Enrichment on Individually Housed Male New Zealand White Rabbits

The beneficial effect of music has been demonstrated in many species. Although commercially available music CDs intended for use with rabbits are available, these enrichments have not been critically evaluated to determine whether they reduce distress. In this study, we used an aging colony of male rabbits to evaluate how the provision of music enrichment affected the wellbeing of the colony. After 6 mo of music enrichment, the rabbits in the colony demonstrated a significant decrease in fecal cortisol, suggesting that their stress was reduced. Six months after removal of the music enrichment, the rabbits demonstrated a significant increase in fecal cortisol and the heterophil:lymphocyte ratio, suggesting that they werestressed. These findings suggest that music enrichment with a commercially available music discs for rabbits can be used toimprove the wellbeing of animals used in biomedical research

Ultrabroad-bandwidth multifrequency Raman generation

We report on the modeling of transient stimulated rotational Raman scattering in H2 gas. We predict a multifrequency output, spanning a bandwidth greater than the pump frequency, that may be generated without any significant delay with respect to the pump pulses. The roles of dispersion and transiency are quantified

The Coalville Deer Herd in Northeastern Utah: Its Ecology and Management

The primary objective of this study on the Coalville Deer Management Unit adjacent to the corner of Wyoming in Utah was to determine the condition of the deer herd in relation to its ranqe and population chatacteristics. Postseason doe-fawn ratio was 100:77, while an adjusted doe-fawn ratio accounting for the unproductive female yearling segment was 100:105. The approximate net-productivity for 1964 was 44 percent compared to 27 percent in 1965. In 1964-65, the average age-class mortality rate for the male and female segments was 45 and 35 percent respectively. Preseason and postseason sex ratios were 64:100 and 60:100 respectively. Mature deer were in good condition during the fall harvest. However, a few yearling males and approximately one-third of the fawns (both sexes) were not in good physical condition. Male deer weights, antler points, length of main beam, and antler diameter 1 inch above the burr increased with age. In contrast, female weights increased until they reached 2.5 years of age, with no significant gains thereafter. Antler diameter was considered a good indicator of physical condition. The summer e1evational distribution of deer coincided with the quaking aspen belt between 7,500 and 9,500 feet. Deer marked with streamers and collars did not substantially increase the summer distribution information above the tag returns. Five to 15 percent more marked deer were shot the first hunt after the tagging operation than in subsequent hunts. The average winter e1evational distribution of the deer was 6,700 feet, although the depth of snow and other climatic variables changed each winter\u27s elevational distribution. Deer management in Unit 19 should be closely geared to deer winter concentration areas. Deer hunting regulations should be based on the winter range condition of the majority of the winter range concentration areas. Those winter range concentration areas in need of further deer population reduction to balance deer numbers with the winter range food supply should have postseason hunts after the fall migration. Tag returns from the hunting season did not indicate differential movement of sex and age classes of deer from winter concentration areas to the summer ranges. The majority of the marked deer summered in the same major drainage where tagged, although fall returns were received from five major drainages. A few deer migrated 60 airline miles from their winter to summer ranges, but the majority migrated less than 15 miles from the tagging site. The mechanism triggering fall migration was snow depth, while new vegetation controlled the spring upward movement. All deer that wintered on the same range did not summer together. In 1926, $0.25 range-use permits were required of deer hunters, while in 1965 the Range Owner\u27s Protective Association (ROPA) assessed a$3.00 fee

Seasonal Evolution of Active Layer Formation in Subarctic Peat Plateaux and Implications for Dissolved Organic Matter Composition and Transfer

Peat-accumulating wetlands are ecosystems whose rate of photosynthetic production of organic matter is greater than that of its decomposition, resulting in a build up of soil organic matter that may take centuries to fully decompose. Carbon (C) stocks within these ecosystems are a function of inputs from photosynthesis, and losses from heterotrophic decomposition. Due to the short growing season and overall cold climate of boreal and tundra regions, C has been accumulating within these landscapes, mostly in soil organic matter, since the last glaciation. Climate change, predicted to result in rising temperatures and increased precipitation, has begun to degrade the underlying permafrost of peat plateaux. Hydrologically, permafrost below the active layer acts as an impermeable layer, similar to bedrock, limiting the movement and storage of groundwater to the seasonally thawed active layer. The presence of seasonal ice in the active layer reduces the hydraulic conductivity and available storage capacity, significantly reducing water infiltration, and potentially increasing the occurrence of surface ponding. Accumulated water in surface pools maintains soil moisture levels for longer periods of time, and are often the locations of the deepest thaw depth due to the downward transfer of latent heat aided by the increased thermal conductivity of the peat in the presence of water. Understanding the linkages between the hydrology, the energy balance, and chemical release into surface and groundwater is essential to predicting the response of these landscapes to future climate change. To examine how Northern peatlands are responding to recent warming, two study sites (62° 27’ N, 114° 31’ W; 62° 33’ N, 114° 00’ W) outside of Yellowknife, NT, were instrumented between October 2012-October 2013 to monitor groundwater carbon chemistry, ground thermal and moisture regimes, organic matter decomposition rates, and active layer development over an entire summer period. An integral precursor to site-wide degradation, surface microtopography has been identified as a major determinant in the future evolution of peat plateaux into permafrost-free, bog-like environments. A Biochambers laboratory peat monolith experiment replicating the climatic conditions of a hummock and a depression in the natural system revealed that during the spring freshet while the ground remains frozen, the largely ice-free hummocks function as water contributors to ice-rich depressions, acting as water catchments. This transfer of water aids in the mobilization of DOM from hummocks into depressions, where it potentially accumulates over long time periods and is susceptible to export as the peat plateaux degrade. The accumulation of water in depressions prevents complete freeze-back of the active layer in the winter, allowing microbial activity and DOC production to occur year-round. The formation of supra-permafrost taliks has also been observed as an outcome of trapped heat beneath the seasonally frozen active layer and above the permafrost table, which, over time, may form interconnected subsurface flowpathways for DOM export. As warming commences over time, it is thought that the physical and carbon chemistry characteristics of the degraded portion of the plateaux may act as a proxy for future landscape change

The development and evaluation of analytical methods for the analysis of trace levels of moisture in high purity gas samples

A Dissertation submitted in fulfillment of the requirements for the degree Master of Science In the Faculty of Sciences at the University of the Witwatersrand, Johannesburg Johannesburg, January 2015Three methods, for the analyses of low levels of moisture in gas samples, were developed and optimized. The analytical techniques included Fourier Transform Infrared Spectroscopy (FTIR) and Pulsed Discharge Helium Ionization/Gas Chromatography (PDHID/GC). The methods included the direct analyses of moisture in gas samples using FTIR as well as the analysis of acetylene (C2H2) by FTIR and GC/PDHID. For the latter methods, the purpose was to convert the moisture in a gas sample to C2H2 by hydrolization of the calcium carbide (CaC2) with moisture to C2H2 and then analyze the resulting C2H2 content by FTIR or GC/PDHID. The C2H2 result was then converted back to moisture to obtain the moisture content of the sample. The FTIR moisture method developed provided eleven different wavenumbers for quantitation providing a wide analytical scope, specifically in complex gas matrices, where there is often peak overlap between matrix and moisture. A heated eight meter glass long path gas cell and a mercury cadmium telluride (MCT) detector were utilized. The FTIR method required much greater volumes of sample than the GC method but allowed for direct analysis of moisture without prior conversion to acetylene. Moisture permeation standards were used for calibration and the LOD’s ranged from 0.5 to 1 ppm with quantification possible from 0.5 to 10ppm. For the FTIR C2H2 method various concentration ranges were established from 50 up to 2000 ppm. Three wavenumbers were evaluated for C2H2 and methane was introduced as an internal standard. The use of methane as an internal standard provided better r2 values on the calibration data than for the tests run without internal standard. A gas chromatographic (GC), pulsed discharge helium ionization detector (PDHID) method for the determination of moisture content in small quantities of gases, based on the conversion of the moisture to acetylene (C2H2) prior to analysis, was developed. The method developed on the GC/PDHID for C2H2, provided a quantitation range from 0.6 to 7.7 ppm. Conversion of the moisture to acetylene was achieved by hydrolysing an excess of calcium carbide (CaC2) in a closed reaction vessel with a measured volume of a sample containing a known quantity of moisture. The gaseous reaction mixture was transferred, using helium (He) carrier gas, to a GC/PDHID, set up with “sample injection and heart cut to detector” to prevent matrix disturbances on the PDHID, for analysis. The acetylene concentration values thus obtained were converted back to moisture values and percentage recoveries calculated. A similar conversion process was applied on FTIR. The conversion of moisture to C2H2 using CaC2 was tested and proven to be viable. Quantification was not possible as the available sample holder could not be adequately sealed to prevent air ingress. This led to higher C2H2 values than expected. This process can be optimized by the design and production of a sealed sample holder