Graduate Theses and Dissertations

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This collections holds all University of Saskatchewan graduate level electronic theses and dissertations (ETDs) published since 2005. More than 700 print theses published before 2005 have been digitized and added to the collection as well.

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Investigating the Role of Nuclear Pore Complex and Nucleocytoplasmic Transport Alterations in Multiple Sclerosis and Related Neurodegenerative Diseases
(2024-05-01) Stang, Todd E; Levin, Michael C; Chlan, Jennifer; Bekar, Lane; Cayabyab, Francisco
Multiple sclerosis (MS), classically known as an autoimmune, demyelinating disease of the central nervous system, has a significant neurodegenerative component which underlies permanent disability in MS patients. Current MS treatments are immunomodulatory and can decrease relapses, but no treatments target neurodegeneration, which drives disease progression. Dysfunctional RNA binding proteins (RBPs) are a common mechanism of many neurodegenerative diseases, including MS. The nuclear pore complex (NPC) and nucleocytoplasmic transport are critical to the proper functioning of cells, but are altered in neurodegenerative diseases, including Huntington’s disease, amyotrophic lateral sclerosis, and Alzheimer’s disease. Previous RNA sequencing data from our lab identified differentially expressed genes related to the NPC and nucleocytoplasmic transport in cells with knockdown of an RBP. The function of the NPC and nucleocytoplasmic transport has yet to be studied in MS. I hypothesized that the NPC is perturbed in MS and a related model of RBP dysfunction, affecting normal nucleocytoplasmic transport, potentially contributing to neurodegeneration. Knockdown of the RBP heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) in Neuro2a cells (a neuronal-like cell line), a model of RBP dysfunction, significantly affected the structure of the nuclear envelope. Next, I generated a novel method to classify Lamin B staining patterns of the nuclear envelope to improve analyses and reduce bias. Using this method, I replicated the finding that hnRNP A1 loss alters the nuclear envelope. The structure of the NPC itself was significantly affected and the expression of two NPC proteins was decreased. Then, using a previous RNA sequencing dataset of hnRNP A1 knockdown, I performed gene ontology analysis and found alterations in pathways related to the NPC and nucleocytoplasmic transport, providing support to the role of the NPC and nucleocytoplasmic transport play in the pathogenesis of MS. The nuclear envelope remained intact, but active nucleocytoplasmic transport was perturbed, leading to mislocalization of a protein undergoing continuous transport through the NPC. I then validated my findings in human tissues and determined that Lamin B staining was significantly altered in MS compared to controls. These results demonstrate that dysfunctional RBPs can affect the nuclear envelope and the NPC. Perturbations in nucleocytoplasmic transport can lead to further protein mislocalization, exacerbating RBP dysfunction and nuclear RNA accumulation thereby affecting protein synthesis. Dysfunctional nucleocytoplasmic transport, which can lead to neuronal cell death, is a novel mechanism implicated in the pathogenesis of MS.
Understanding the Determinants of X-Minute City Policies and the differences and barriers to achieving X-minute city policies
(2024-05-01) Lu, Michael; Bell, Scott M.; Mou, Haizhen; Patrick, Robert
The abstract of this item is unavailable due to an embargo.
ANALYZING CANADIAN LAWS ON RECREATIONAL CANNABIS EDIBLES FROM A PUBLIC HEALTH PERSPECTIVE
(2024-05-01) Goundar, Priyashni; Mansell, Holly; Szafron, Michael; Labrecque, Mary Ellen; Lepnurm, Rein
Background The Canadian government amended the Cannabis Act and Cannabis Regulations to legalize use of recreational cannabis edibles. Edibles are food products and beverages that contain chemical compounds from the cannabis plant. Developing legislation is challenging given both food and drug related hazards must be mitigated; additionally, few jurisdictions have experience regulating edibles. Besides Canada, the United States of America (USA) is the only other country with experience regulating cannabis edibles at the state-level. Hence the objectives for this thesis were to: (i) compare laws (within Canada and the U.S. states that have legalized the recreational use of cannabis edibles) that govern tetrahydrocannabinol (THC)-infused cannabis edibles and identify any associated gaps in Canada's cannabis regulatory framework; (ii) identify potential food safety hazards and health hazards associated with manufacturing cannabis edibles; and (iii) compare the Safe Food for Canadians Act (SFCA) and Safe Food for Canadians Regulations (SFCR) with the Cannabis Act and Cannabis Regulations to identify potential food safety gaps in the Canadian cannabis legislation. Methods The Canadian documents containing the information necessary for objective (i) are the Canadian Cannabis Act, Cannabis Regulations, and the Health Canada report: Final Regulations for New Cannabis Products published in the Canada Gazette. The necessary U.S. state-level statutes and regulations were retrieved for all U.S. states with laws on recreational cannabis from LexisAdvance Quicklaw. A comparative analysis of these documents highlighted similarities and differences in the cannabis regulatory framework of Canada and the U.S. states with laws on recreational cannabis edibles. For objective (ii), to identify potential food safety hazards and health hazards associated with manufacturing cannabis edibles, a rapid review was conducted. The PubMed database was searched. All 11 articles retrieved were reviewed. From the references within these articles, an additional 14 articles were identified and reviewed. Lastly, for research objective (iii), cannabis legislation (Cannabis Act and Cannabis Regulations) and food safety legislation (SFCA and SFCR) were taken from the Government of Canada website. The two sets of legislation were compared to determine which food safety-related requirements were incorporated into the Cannabis Act and Cannabis Regulations and which were omitted. Results As of June 20th, 2019, twelve jurisdictions in the USA authorized recreational cannabis use, but only ten states outlined specific requirements for edibles. Overall, Canada and states in the USA that legalized recreational cannabis edibles implemented similar regulatory requirements; however, restrictions on THC per package and labelling requirements were more conservative in Canada. Differences in regulatory requirements between both countries were also identified. Requirements on reporting of test results and data collection via the cannabis tracking system differed between Canada and the USA. Moreover, four U.S. states require cannabis manufacturers to directly imprint edibles with a cannabis symbol, which is not mandated in Canada. With respect to food safety, to prevent food-borne illnesses, the Cannabis Regulations adapted food safety requirements from the SFCR to prevent contamination of ingredients during the production of edibles. These requirements pertain to standard operating procedures, filtration systems, sanitation, quality assurance and hazard control plans. Gaps in regulatory requirements were also identified and include: (i) two food-safety related clauses from the SFCR that were not incorporated in the Cannabis Regulations; and (ii) the Cannabis Tracking and Licensing System (CTLS) does not collect data from licensed laboratories. Conclusion This thesis project analyzed Canada’s regulatory framework for recreational cannabis edibles to determine whether legislative requirements would adequately mitigate public health risks by comparing it to state-level statutes in the USA and to understand Canadian legislative requirements on food safety as applied to cannabis edibles and assess the legislation’s adequacy in mitigating potential food safety related risks. Overall, Canada’s regulatory requirements on cannabis edibles are comprehensive and will be critical in minimizing public health risks, including food safety related risks. Canada’s cannabis legislation can be further strengthened by mandating manufacturers to directly imprint edibles with a cannabis symbol and addressing requirements on test result reporting and data collection via the CTLS.
Nutrient Management Practices for the Optimization of Organic Milling Oat (Avena sativa)
(2024-04-30) Peters, Racquelle A; Shirtliffe, Steve; Entz, Martin; Bourgault, Maryse; Bennet, Jonathan; Lynch, Derek
The abstract of this item is unavailable due to an embargo.
Use of Bismuth Subsalicylate to Mitigate Effects of Water with High Sulfate Concentrations for Beef Cattle
(2024-04-30) Evans, Mikaela Gaylene; Penner, Greg; Campbell, John; Ribeiro, Gabriel; Brook, Ryan; Wyffels, Samuel
Heifers consuming high-sulfate water are at an increased risk for depletion of Cu and or S-induced polioencephalomalacia and limited mitigation strategies are available. Study 1 evaluated the effect of water with increasing sulfate concentration on dry matter (DM) and water intake, and ruminal fermentation. Eight ruminally cannulated beef heifers (382 ± 45 kg) were stratified into two complete and one incomplete Latin squares with 28-d periods and exposed to 342 ± 29 (LS), 2,785 ± 72 (MS), or 4,948 ± 163 mg of sulfate/L (HS). At the end of each period, digesta was collected from heifers in the complete squares and used for in vitro incubation to evaluate the effect of water sulfate and BSS dose (0.0, 0.2, 0.4, and 0.6% of diet DM) in a 3 × 4 factorial design. Water intake increased linearly (P < 0.01) with increasing sulfate concentration, but dry matter intake (DMI) was not affected (P = 0.23). Heifers provided MS and HS had greater ruminal hydrogen sulfide (H2S) concentration for 10.5 h after water provision and HS continued to be greater for another 4 h relative to LS (sulfate  h, P < 0.01). In vitro H2S production increased (P < 0.01) with increasing sulfate concentration and was reduced (P = 0.05) by BSS. Study 2 evaluated the effects of feeding 24 growing beef heifers (221 ± 41 kg) BSS (0.0 vs. 0.4% (DM basis)) when provided water with a low (346 ± 13 mg/L) or high (4,778 ± 263 mg/L) sulfate concentration in a 91-d feeding study (completely randomized block design). Evaluated effects included DMI, water intake, ruminal H2S concentration, and trace mineral status. DMI and water intake were not affected by sulfate or BSS (P ≥ 0.10). The inclusion of BSS reduced (P = 0.035) ruminal H2S concentration by 46%. Heifers fed BSS had lower liver Cu than heifers not provided BSS and heifers provided high sulfate had lower liver Cu than those provided low (sulfate × BSS, P = 0.02). While BSS reduced ruminal H2S, it’s not a suitable mitigation strategy as it further decreased trace mineral status of beef cattle.
Use of Bismuth Subsalicylate to Mitigate Effects of Water with High Sulfate Concentrations for Beef Cattle
(2024-04-30) Evans, Mikaela Gaylene; Penner, Greg; Campbell, John; Ribeiro, Gabriel; Brook, Ryan; Wyffels, Samuel
Heifers consuming high-sulfate water are at an increased risk for depletion of Cu and or S-induced polioencephalomalacia and limited mitigation strategies are available. Study 1 evaluated the effect of water with increasing sulfate concentration on dry matter (DM) and water intake, and ruminal fermentation. Eight ruminally cannulated beef heifers (382 ± 45 kg) were stratified into two complete and one incomplete Latin squares with 28-d periods and exposed to 342 ± 29 (LS), 2,785 ± 72 (MS), or 4,948 ± 163 mg of sulfate/L (HS). At the end of each period, digesta was collected from heifers in the complete squares and used for in vitro incubation to evaluate the effect of water sulfate and BSS dose (0.0, 0.2, 0.4, and 0.6% of diet DM) in a 3 × 4 factorial design. Water intake increased linearly (P < 0.01) with increasing sulfate concentration, but dry matter intake (DMI) was not affected (P = 0.23). Heifers provided MS and HS had greater ruminal hydrogen sulfide (H2S) concentration for 10.5 h after water provision and HS continued to be greater for another 4 h relative to LS (sulfate  h, P < 0.01). In vitro H2S production increased (P < 0.01) with increasing sulfate concentration and was reduced (P = 0.05) by BSS. Study 2 evaluated the effects of feeding 24 growing beef heifers (221 ± 41 kg) BSS (0.0 vs. 0.4% (DM basis)) when provided water with a low (346 ± 13 mg/L) or high (4,778 ± 263 mg/L) sulfate concentration in a 91-d feeding study (completely randomized block design). Evaluated effects included DMI, water intake, ruminal H2S concentration, and trace mineral status. DMI and water intake were not affected by sulfate or BSS (P ≥ 0.10). The inclusion of BSS reduced (P = 0.035) ruminal H2S concentration by 46%. Heifers fed BSS had lower liver Cu than heifers not provided BSS and heifers provided high sulfate had lower liver Cu than those provided low (sulfate × BSS, P = 0.02). While BSS reduced ruminal H2S, it’s not a suitable mitigation strategy as it further decreased trace mineral status of beef cattle.
Verification and Analysis Development for Proposed Bethe-Heitler Pair Production Asymmetry Experiment
(2024-04-30) Godhe, Alexander Sean; Pywell, Rob; Toohey, Matthew; Moewes, Alexander; Boland, Mark; Spiteri, Ray
This thesis shows the simulated results of the proposed Bethe-Heitler Pair Production Energy Asymmetry experiment. This asymmetry measurement is an emergent property of the 2nd order cross-section of electron-positron pair production and therefore an important measure of higher order effects of the field theory. The simulated limits of the measurement are determined and reported as they would be relevant to the experimentalist. The analysis performed on the simulated data was done using principal component analysis and linear regression of modified, non-linear data. The results as found by this work support the current experiment design being capable of producing a cross-sectional asymmetry measurement but with poor resolutions in both energy and angle calculations. Possible avenues to improve the effectiveness of the design are put forward and the methods of analysis are detailed such that any future design revisions can be reviewed efficiently.
BIOTRANSFORMATION OF 6PPD-QUINONE IN VIVO, EX SITU, IN SILICO, AND IN VITRO: A POTENTIAL TOXICOKINETIC EXPLANATION FOR DIFFERENCES IN SPECIES SENSTIVITY
(2024-04-30) Montgomery, David James; Brinkmann, Markus; Hecker, Markus; Weber, Lynn; Hogan, Natacha; Alcorn, Jane
The ubiquitous toxicant, 6PPD-Quinone (6PPD-Q), originates from the environmental oxidation of 6PPD, an antioxidant found in rubber tires and other rubber products. 6PPD-Q is dispersed from roadways during rain events to nearby waterways such as rivers, creeks, streams, and lakes. Subsequently, species living in these environments are exposed to 6PPD-Q, which causes acute lethality in select species of fishes. While 6PPD-Q was determined as non-toxic to invertebrates such as rotifers or cladocerans, some species of fishes, including coho salmon, rainbow trout, and brook trout, display symptoms of urban runoff mortality syndrome (URMS) with a specifically rapid onset of mortality (4 hours for coho salmon). Peak concentrations of 6PPD-Q causing URMS are relatively short-lived due to the rapid degradation of 6PPD-Q in water. It is important to note that 6PPD-Q degradation may play a major role in determining if a species will have mass die-offs in the environment, although it is not the scope of this research. While the abovementioned species of fishes are sensitive to 6PPD-Q, other fishes appear to be insensitive at relatively high concentrations that are past currently measured environmental concentrations. While the reasons for these marked interspecies differences in sensitivity are presently unknown, it has been hypothesized that metabolic differences among fish species are responsible, i.e., their differential ability to biotransform 6PPD-Q and influence the amount of 6PPD-Q reaching the gills in recirculation of blood. The objectives of this thesis aimed to explain interspecific sensitivity to 6PPD-Q via quantifying toxicokinetic (TK) parameters. Assessments measured ex situ hepatic clearance and extraction fraction (in rainbow trout), in vivo biliary metabolite identification and abundance (in various fishes) in addition to in vitro intrinsic clearance (in rainbow trout and Arctic char). Lastly, ex situ hepatic transport, and cytochrome P450 identification (assessed in vitro) were also assessed. Semi-quantification of biliary metabolites after in vivo exposure pointed toward a possible TK explanation for the interspecies differences in sensitivity to 6PPD-Q, i.e., sensitive species exhibited a decreased ability to detoxify 6PPD-Q compared to insensitive species. Ex situ perfused liver experiments suggested that rainbow trout are moderate to rapid metabolizers of 6PPD-Q, suggesting even rapidly biotransformed 6PPD-Q may be insufficient to prevent the acute responses observed in vitro with gill cells, potentially leading to lethality in vivo at environmentally relevant concentrations. Results from in vitro experiments with fish hepatocytes were inconclusive due to low basal metabolic activity. Further studies are necessary to optimize the in vitro assays for the assessment of interspecies differences in biotransformation rates and activities of common cytochrome P450s. In summary, this thesis provided important insights into interspecies differences in 6PPD-Q detoxification. Phase I and II metabolite abundance were correlated with sensitivity or exposure concentration, indicating these compounds might be useful in predicting toxic responses in fishes and might be assessed as a potential biomarker of exposure. Furthermore, ex situ results indicate that rainbow trout, a species known to be sensitive to 6PPD-Q exposure, is a moderate to rapid detoxifier, which might be inconsistent with the in vivo results that suggest rainbow trout have a relatively low capacity to detoxify 6PPD-Q. Bile metabolite levels are a crude measurement of overall systemic detoxification, tissue-specific biotransformation rates might be another important driver of 6PPD-Q toxicity. Future studies should aim to explain the discrepancy between ex situ and in vivo results and other studies should include detoxification of 6PPD-Q as an included component of their studies if interspecific differences in sensitivity are of interest. Further assessment in vitro is necessary to develop assays which could significantly reduce animal use in the future.
AN EVALUATION OF THE EFFECTS OF ANTHROPOGENIC ABIOTIC DISTURBANCE ON THE FORAGING BEHAVIOURS OF DYTISCUS SPP. LARVAE OF SASKATCHEWAN
(2024-04-30) Ulrich, Jacob Christopher; Chivers, Doug; Ferrari, Maud; Phillips, Iain; Gray, Jack; Prager, Sean; Chilton, Neil
With urbanization practices, humans are altering the nature of abiotic stimuli to which animals are exposed. Understanding how animals deal with these disturbances may be critical from a management perspective, to minimize effects while still allowing for industrial development. I investigated the hunting success of predatory larvae of Dytiscus spp. in relation to four abiotic stimuli that are affected by encroachment on aquatic ecosystems (wind, ground vibrations, turbidity, and temperature). Dytiscus spp. are dispersed globally and will experience encroachment in the future. They have charismatic hunting behaviours that may be prone to disturbance. Survival trials were conducted using larval Dytiscus spp. as predators and adult Gammarus lacustris as prey. Organisms were exposed to either a high, low, or absent (control) level of disturbance from each of the four stressors in different experiments. Each survival trial featured a five-minute separated acclimation period after which the predator and prey were allowed another five minutes to interact. Both individuals were recorded and behavioural differences among treatment groups (no vs. low vs. high disturbance) were assessed with regards to general activity as well as other behaviours. Despite finding no significant difference in overall prey consumption because of manipulating abiotic disturbances, results suggest that Dytiscus larvae switch from an ambush strategy to opportunistic strategies in disturbed environments. Also, the intensity of the abiotic stimuli and the water temperature may additionally increase variance of these behaviours. Ambush behaviours tend to occur in calm clear 23 ̊C water while opportunistic foraging occurs in disturbed environments but will reduce in speed as turbidity increases. Additionally, it appears that novel abiotic stimuli may have a significant effect on predatory behaviours. It remains a question as to how Dytiscus larvae decide to use ambush foraging behaviour and what levels of interference will change their behaviour. However, this project serves as the groundwork for future experiments investigating the role of abiotic impairment in aquatic insect predators. With an ever-expanding human population, and industrial development, we should seek solutions to mitigate potential changes to aquatic communities and the problems they pose to aquatic invertebrate predators.
PHYSIOCHEMICAL AND NUTRIENT PROPERTIES AND TRUE NUTRIENT SUPPLY OF WHOLE OAT GRAINS IN RUMINANT SYSTEMS: EFFECT OF OAT VARIETIES AND TYPES (FEED TYPE VS. MILLING TYPE)
(2024-04-26) Deng, Ganqi; Yu, Peiqiang; Christensen, David; Lardner, Herbert (Bart); Brook, Ryan
The general objectives of this study were to determine the effect of four varieties and two types of oats (feed type vs. milling type) on the physiological and nutrient properties and true nutrient supply in ruminant system as an alternative feed source for ruminants. This project was carried out in three major phases. In the first phase, results showed that CDC Nasser had highest EE, NPN and lowest ADL among four varieties (P<0.05). CDC Haymaker had highest CP content among four oat varieties (P<0.05), and the value of iNDF120h on CDC Haymaker were largest among four varieties. CDC Nasser had highest TDN and energy values among four varieties (P<0.05). Based on the CNCPS 6.5 model, the CC fraction of CDC Nasser was lowest among four varieties (P<0.05). In the second phase, results also showed that CDC Haymaker and Arborg had higher Kd of DM, CP, and starch than that of CDC Nasser (P<0.05), and these Kd values of CDC Nasser were much smaller than other oat varieties. The EDDM, EDCP, and EDST of CDC Nasser were smallest among varieties as well (P<0.05). Oat varieties also had significant impact on N/OM and ED_N/ED_OM, and CDC Arborg was closest to the optimal ratio of ED_N/ED_OM (25 g/kg). In the third phase, results revealed that CDC Nasser had lowest MREE, DVME, DVE and FMV based on the Dutch DVE/OEB system (P<0.05), and all the OEB values of oats were much larger than zero indicating had potential N losses in the rumen. As for the oat types, significant impact was observed on EE, CP, NPN, ADL, TDN, Kd of DM, starch and CP, BDM, EDDM, BST, EDST, TDDM, TDST, DVE, OEB and FMV between feed and milling type (P<0.05). Milling oats had higher non-fiber carbohydrate values, while feed oats had higher structure carbohydrate values and FMV comparing to milling oats. In conclusion, all the oat varieties could be a good feed source for the dairy cows. CDC Nasser had largest TDN and energy values on dairy cows. CDC Nasser was the optimal variety to replace the barley grains of rations of dairy cattle based on this study.
The loss of matrix norm equivalence in big data analysis and the Marchenko-Pastur Law
(2024-04-26) Heidorn, Emma Fan; Wang, JC; Li, Longhai; Xing, Li; Rayan, Steven
In statistics, p dimensional data are collected n times. Traditionally, the dimension of p would be larger than n; however, as technology progresses, we enter the era of big data where n is no longer much larger than p. The large ratio of p n causes pitfalls in methods and algorithms that were developed with the opposite in mind. To solve this problem, methods using random matrix theory were brought up in [4], this thesis will be focusing on results concerning the Marchenko-Pastur Law. This thesis is not a cutting-edge research, but an organized presentation of the Marchenko- Pastur Law. This is written so students and researchers can quickly grasp the ideas and methods without difficulty.
Identification of QTL and Candidate Genes for Protein Concentration and Protein Quality in Pea (Pisum sativum L.)
(2024-04-26) Zhou, Junsheng; Warkentin, Tom; Bueckert , Rosalind; Nickerson, Michael; Tar’an, Bunyamin; Willenborg, Christian; Duncan, Robert
The abstract of this item is unavailable due to an embargo.
Using Minimally Invasive Sampling Methods to Evaluate Polar Bear (Ursus maritimus) Visitation in Response to Environmental and Anthropogenic Stimuli
(2024-04-25) Rivet, Danielle R; Clark, Douglas A; Wilson, Kenneth E; Brook, Ryan K; McLoughlin, Philip D; Benson, James D; Thiemann, Gregory W; Rode, Karyn D; Todd, Christopher D
Polar bears (Ursus maritimus) are spending more and more time on land in an increasingly warming Arctic, raising concerns for both human safety and polar bear conservation. This research aimed to investigate the ecological and anthropogenic influences on polar bear visitation to infrastructure in western Hudson Bay, and how these factors drive the growing risk for human-polar bear conflict. More specifically, examining the links between sea ice breakup and freeze-up dates, the length of the onshore season, polar bear body condition, human presence, and polar bear visitation to infrastructure shed light on valuable insights into the complex interplay between environmental conditions, human activities, and the potential for conflict between humans and polar bears, ultimately informing management efforts. The data for this project were collected via a combination of camera trap surveys, evaluation of sea ice charts, and human use observations in the western Hudson Bay region. Using mixed effects logistic regressions, generalized linear models, and negative binomial regressions, I validated camera trap efficacy for monitoring polar bear populations, evaluated the relationship between changing sea ice, polar bear body condition, and patterns in polar bear visitation to infrastructure, and determined the effects of body condition and levels of human presence on polar bear visitation frequency. In western Hudson Bay, lone female bears were in the best body condition, while females with young, especially cubs of the year, tended to be in the worst body condition, suggesting a potential paradigm shift away from subadults being the bears most involved in human-polar bear interactions and conflict. Moreover, polar bears in this region were observed more frequently at infrastructure during years where the ice-free season is the longest, increasing chances of interactions with people. However, neither the Churchill Northern Studies Centre nor the remote camps in Wapusk National Park were serving as attractants to polar bears, and the group size or duration of human presence did not play an important role in this. Lastly, I determined camera trapping surveys are a valid method of monitoring polar bear populations, but multi-camera setups are encouraged for highest efficacy. Further monitoring is warranted. While camera traps are a reliable method for monitoring polar bear populations, especially for Arctic communities, an expansion of the camera array on the landscape and collaboration with Indigenous communities will help to create a more robust data set with higher statistical power and from which to make better inferences in the future.
Effect of Root Carbon on Microbial Abundance and Carbon Cycling in the Topsoil and Subsoil
(2024-04-25) Adams, Kehinde; Helgason, Bobbi; Peak, Derek; Arcand, Melissa; Mevin, St Luce
Understanding the interaction between root carbon (C), microbial C cycling and soil organic matter (SOM) dynamics is crucial for C sequestration. This study aimed to look at the interaction between root C, soil microorganisms and their microhabitat on microbial C cycling and the potential for more SOM storage on a cropland. We investigated the turnover of root exudate proxies (glucose, alanine, and citric acid) and their effect on short term apparent soil organic carbon (SOC) priming and microbial abundance in cropland soils obtained from different depths (10-15 cm, 30-35 cm, 50-55 cm). We added exudates to 30 g soil at rate of 28.3 mg C g-1 SOC and measured CO2 fluxes over 408 hrs under controlled conditions and their effect on apparent priming within 22 hrs. The normalized CO2 efflux to the concentration of substrate C added was lowest at the 50-55 cm depth, indicating greater substrate C retention in the 50-55 cm soil. CO2 efflux from citric acid addition was higher than from glucose and alanine at the 10-15 cm and 30-35 cm depths and resulted in the greatest SOC priming. Alanine addition resulted in a notable increase in microbial abundance after a 22-hour period in comparison to both the control soil and other added substrates. We further conducted a field study, mixing canola root with soil from the topsoil (10-15 cm) and with the subsoil (50-55 cm) at different rates (high root biomass vs low root biomass), to test the effect of root biomass rate on C storage in different SOM fractions (mineral associated organic matter and particulate organic matter) and microbial abundance. Using reciprocal transplant, the litterbag mixture was placed at the same depth of soil collection (non-translocated) or flipped (translocated) to evaluate the effect of microhabitat on microbial abundance and C storage. We found that microhabitat but not the root biomass quantity affected microbial abundance and community structure. This finding suggests the potential for more C storage at depth due to the ability of deeper soil layers to retain more C, because of the lower mineralization rates and microbial abundance observed in the subsoil.
The effects of LED light flicker on turkey hen production, health, and welfare to 11 weeks of age
(2024-04-25) Hammond, April Elena; Schwean-Lardner, Karen; Crowe, Trever; Brown, Jennifer; Brook, Ryan; Carney, Valerie
This study examined the impacts of light-emitting-diode flicker on Nicholas Select turkey hens (n=3267) to 11 weeks (wk) of age. There were three treatments: the 30 Hertz (Hz) treatment (30HZ) the 90 Hz treatment (90HZ) and the 195 Hz treatment (195HZ). Birds were randomly assigned to nine independently controlled rooms (364 birds/room at placement). Performance was evaluated through body weight (BW) at 0 days (d), 4, 8, and 11 wk of age. At 0d-4, 4-8, and 8-11 wk BW gain, feed intake (FI) and feed-to-gain ratio were examined. At 10 wk, a sample of 30 birds/room was individually weighed to examine uniformity. Mortality and culls were also collected twice daily. Video recordings were taken at 4, 8, and 10 wk for 18 hrs which were scan sampled at 20-minute intervals to determine the percentage of time (%t) birds spent performing different behaviours. At 10 wk, 20 birds/room were examined for mobility (gait score), footpad lesions, feather condition, and feather cleanliness. At 11 wk 4 birds/room were euthanized and the right eyeball was excised and measured for weight, medio-lateral diameter, dorso-ventral diameter (DV), and anterior-posterior size (AP). Heterophil-to-lymphocyte (H/L) ratios were determined using blood samples at 4, 8, and 11 wk (20 birds/room). Litter quality was examined at 11 wk. Incidences of aggressive damage on birds were monitored twice daily. For the first 7 d and at 4, 8, and 11 wk, a novel object test (NOT) was performed to examine fearfulness. Data were analyzed using Proc Mixed (SAS 9.4). Tukey’s range test was used to separate means with significance declared when P<0.05. Birds in the 30HZ weighed less than those in the 195HZ at 8 wk with those in the 90HZ intermediate (P=0.025). The birds in the 30HZ had higher BW gain from 8-11 wk compared to those in the 90HZ with those in the 195HZ intermediate (P=0.003). From 0d-4 wk and 4-8 wk, birds in the 30HZ had reduced FI (P≤0.001, 0.001, respectively). Mortality corrected feed-to-gain was improved from 8-11 and 0d-11 wk in the 30HZ compared to the 90HZ with the 195HZ intermediate (P=0.048, 0.040 respectively). Infectious mortality was reduced (P=0.049) in the 195HZ versus the 90HZ from 0d-11 wk with the 30HZ intermediate. Total mortality was reduced in the 195HZ from 0d-11 wk (P=0.024) and 0d-4 wk (P=0.005). From 4-8 wk, round heart mortality was higher in the 30HZ (P=0.040). Footpad scores of 0 were seen more frequently for birds in the 90HZ, resulting in better average footpad scores (P=0.011, 0.021, respectively). Average feather cleanliness was improved and scores of 1 were more frequent for birds in the 90HZ compared to those in the 195HZ with those in the 30HZ intermediate (P=0.021, 0.030, respectively). Flicker frequency did not affect litter quality or NOT. The DV (P=0.046) and AP (P=0.033) of birds in 30 Hz were increased compared to 195 and 90 Hz, respectively. Bird behaviour varied across treatments with no clear pattern. The %t birds spent gentle feather pecking was reduced at 4 and 8 wk in the 30HZ (P=0.040, 0.016 respectively). At 8 wk, %t wing flapping was reduced by birds in the 195HZ (P=0.004). The %t birds spent fighting (P=0.049) and aggressive pecking (P=0.022) was reduced in the 30HZ compared to the 90HZ at 8 wk with the 195HZ intermediate. Birds reduced the %t preening in the 30HZ compared to the 90HZ and 195HZ at 10 wk (P=0.034). Incidences of aggressive damage were reduced at all ages at various locations for birds in the 30HZ with the exception of damage directed towards the neck at 11 wk (P<0.001). The H/L ratio of birds in the 30HZ was reduced compared to those in the 195HZ at 11 wk with those in the 90HZ intermediate (P=0.044). Overall, visible light flicker had negative impacts on production early in a turkey’s life; however, effects were not seen by the end of the production period. Aggression was reduced under the 30HZ; however, this may not be beneficial as other behaviours indicate this may have been due to a reduction in activity. Stress also seems to be reduced, based on H/L ratios, when lamps flicker at 30 Hz, though this is likely due to the reduction in aggression rather than a direct effect of flicker.
The effects of LED light flicker on turkey hen production, health, and welfare to 11 weeks of age
(2024-04-25) Hammond, April Elena; Schwean-Lardner, Karen; Crowe, Trever; Brown, Jennifer; Brook, Ryan; Carney, Valerie
This study examined the impacts of light-emitting-diode flicker on Nicholas Select turkey hens (n=3267) to 11 weeks (wk) of age. There were three treatments: the 30 Hertz (Hz) treatment (30HZ) the 90 Hz treatment (90HZ) and the 195 Hz treatment (195HZ). Birds were randomly assigned to nine independently controlled rooms (364 birds/room at placement). Performance was evaluated through body weight (BW) at 0 days (d), 4, 8, and 11 wk of age. At 0d-4, 4-8, and 8-11 wk BW gain, feed intake (FI) and feed-to-gain ratio were examined. At 10 wk, a sample of 30 birds/room was individually weighed to examine uniformity. Mortality and culls were also collected twice daily. Video recordings were taken at 4, 8, and 10 wk for 18 hrs which were scan sampled at 20-minute intervals to determine the percentage of time (%t) birds spent performing different behaviours. At 10 wk, 20 birds/room were examined for mobility (gait score), footpad lesions, feather condition, and feather cleanliness. At 11 wk 4 birds/room were euthanized and the right eyeball was excised and measured for weight, medio-lateral diameter, dorso-ventral diameter (DV), and anterior-posterior size (AP). Heterophil-to-lymphocyte (H/L) ratios were determined using blood samples at 4, 8, and 11 wk (20 birds/room). Litter quality was examined at 11 wk. Incidences of aggressive damage on birds were monitored twice daily. For the first 7 d and at 4, 8, and 11 wk, a novel object test (NOT) was performed to examine fearfulness. Data were analyzed using Proc Mixed (SAS 9.4). Tukey’s range test was used to separate means with significance declared when P<0.05. Birds in the 30HZ weighed less than those in the 195HZ at 8 wk with those in the 90HZ intermediate (P=0.025). The birds in the 30HZ had higher BW gain from 8-11 wk compared to those in the 90HZ with those in the 195HZ intermediate (P=0.003). From 0d-4 wk and 4-8 wk, birds in the 30HZ had reduced FI (P≤0.001, 0.001, respectively). Mortality corrected feed-to-gain was improved from 8-11 and 0d-11 wk in the 30HZ compared to the 90HZ with the 195HZ intermediate (P=0.048, 0.040 respectively). Infectious mortality was reduced (P=0.049) in the 195HZ versus the 90HZ from 0d-11 wk with the 30HZ intermediate. Total mortality was reduced in the 195HZ from 0d-11 wk (P=0.024) and 0d-4 wk (P=0.005). From 4-8 wk, round heart mortality was higher in the 30HZ (P=0.040). Footpad scores of 0 were seen more frequently for birds in the 90HZ, resulting in better average footpad scores (P=0.011, 0.021, respectively). Average feather cleanliness was improved and scores of 1 were more frequent for birds in the 90HZ compared to those in the 195HZ with those in the 30HZ intermediate (P=0.021, 0.030, respectively). Flicker frequency did not affect litter quality or NOT. The DV (P=0.046) and AP (P=0.033) of birds in 30 Hz were increased compared to 195 and 90 Hz, respectively. Bird behaviour varied across treatments with no clear pattern. The %t birds spent gentle feather pecking was reduced at 4 and 8 wk in the 30HZ (P=0.040, 0.016 respectively). At 8 wk, %t wing flapping was reduced by birds in the 195HZ (P=0.004). The %t birds spent fighting (P=0.049) and aggressive pecking (P=0.022) was reduced in the 30HZ compared to the 90HZ at 8 wk with the 195HZ intermediate. Birds reduced the %t preening in the 30HZ compared to the 90HZ and 195HZ at 10 wk (P=0.034). Incidences of aggressive damage were reduced at all ages at various locations for birds in the 30HZ with the exception of damage directed towards the neck at 11 wk (P<0.001). The H/L ratio of birds in the 30HZ was reduced compared to those in the 195HZ at 11 wk with those in the 90HZ intermediate (P=0.044). Overall, visible light flicker had negative impacts on production early in a turkey’s life; however, effects were not seen by the end of the production period. Aggression was reduced under the 30HZ; however, this may not be beneficial as other behaviours indicate this may have been due to a reduction in activity. Stress also seems to be reduced, based on H/L ratios, when lamps flicker at 30 Hz, though this is likely due to the reduction in aggression rather than a direct effect of flicker.
SOIL PHOSPHORUS AND NITROGEN EXPORT AND RETENTION IN RAINFALL RUN-OFF FROM MANURED LANDSCAPES
(2024-04-25) Hlus, Quinn; Schoenau, Jeff; Asgedom, Haben; Si, Bingcheng; Stewart, Katherine; Peak, Derek
Rainfall run-off from manured agricultural fields can be high in nitrogen (N) and phosphorus (P) due to excess nutrient application that is unused by crops. This can pose the risk of eutrophication of nearby surface water bodies receiving run-off. The objective of this study was to determine the effectiveness of precision variable rate application of feedlot cattle manure compared to traditional constant rate applications on nutrient losses in rainfall run-off. A silage barley field at the Livestock and Forage Center of Excellence (LFCE) research facility near Clavet, SK was used for the field study. Additionally, the ability of gypsum and biochar to reduce nutrient losses in leachate was evaluated in a controlled environment study. For the field study, three zones utilizing different nutrient application strategies with three replicate micro-watersheds within each zone were used. The zones were precision variable rate manure application with setbacks from micro-watershed basins, traditional constant rate manure application with no setbacks, and a commercial fertilizer (control) application zone which only received annual synthetic fertilizer applications. The manured zones received manure applications in the spring of 2019 and 2021. Rainfall simulations were conducted in each micro-watershed at different landscape positions (upper east, upper west and depression) in the summers of 2021 and 2022 and nutrient concentrations were measured in the collected run-off. For the controlled environment study, nutrient concentrations in actual rainfall collected from the constant rate and variable rate manure zones was measured before and after being added to columns of soil that were either unamended, or amended with cattle manure-derived biochar or gypsum to determine the effectiveness of these amendments in removing nutrients from leachate. The mean concentrations of total dissolved and soluble reactive P (SRP) in simulated rainfall run-off from the landscape positions were significantly lower in the variable rate manure zone than the constant rate zone in the year of manure application. Biochar did not sorb any nutrients from leachate except for nitrate-nitrogen (NO3--N) in the 2022 season. Both biochar and gypsum contributed ammonium-nitrogen (NH4+-N) to leachate consistently, and gypsum sorbed SRP from leachate in both study years. The contributions of nutrients from biochar to leachate is attributed to the biochar feedstock material (manure) containing high concentrations of nutrients. Variable rate manure application with setbacks may be considered a suitable management practice to limit the export of nutrients in run-off, thus limiting potential negative environmental impacts. Further research is needed to better characterize the contribution/ sorption of nutrients by biochar and gypsum.
Characterization of Psilocin and Psilocybin Pharmacodynamics in Mouse Models for the Development of Novel Anti-Depressants
(2024-04-25) Ezeaka, Udoka Chidinma; Lapriarie, Robert; Lapriarie, Robert; Dadachova, Ekaterina; Chlan-Fourney, Jenifer; Evans, Charity; Botterill, Justin
The abstract of this item is unavailable due to an embargo.
Developing human anti-MUC4 antibodies for the targeted therapy of pancreatic ductal adenocarcinoma
(2024-04-25) Bato, Katrina Erika M; Uppalapati, Maruti Chandra; Taghibiglou, Changiz; Krishnan, Anand; Toosi, Behzad
The abstract of this item is unavailable due to an embargo.
LEVEL OF SUPPLEMENTAL FAT IN PREGNANT BEEF COW DIETS DURING MID-TO-LATE GESTATION: EFFECTS ON PERFORMANCE OF THE DAM AND PROGENY FROM BIRTH TO WEANING
(2024-04-24) Cornand, Erika E.; Lardner, Herbert (Bart) A.; McKinnon, John J.; Fitzsimmons, Carolyn J.; Larson, Kathy A.; Swanson, Kendall; Penner, Gregory B.
A 2-year study evaluated the effects of feeding a canola-based (7.4% ether extract) pellet to gestating cows on cow performance, reproductive efficiency, milk yield and composition, blood metabolite concentrations, and calf performance until weaning. Each yr, 72 pregnant cows were stratified by stage of gestation (111 ± 20 d) and body weight (BW; 619 ± 50 kg), allocated to 12 pens in a randomized complete block design. Pens were randomly assigned to 1 of 3 replicated (n = 4/yr) dietary treatments: 0 (CON), 150 (LOW), and 300 (HIGH) g of fat/d from canola pellet (DM basis). Diets were formulated to be isonitrogenous (CP: 8.40 ± 0.40%) and isocaloric (TDN: 59.78 ± 1.05%), while meeting NASEM (2016) nutrient requirements for pregnant beef cattle. Treatments were fed during the last two trimesters of gestation (148 ± 3 d) based on a dry matter intake of 1.89% of treatment average BW and transitioned to a common diet at the end of the feeding trial. Orthogonal contrasts were used to assess linear and quadratic relationships between fat inclusion and dependent variables. Differences were detected in body condition score (BCS; 1-5 scale; P = 0.03) and rib fat thickness (P < 0.05) at the start of trial, thus were included as covariates in the analysis of all related variables at subsequent time points. BW and conceptus corrected BW tended to linearly increase (P = 0.10 and 0.07, respectively) and the percentage of thin cows (BCS ≤ 2.5) linearly decreased (P = 0.01) across treatments at calving. As fat inclusion increased, BCS change from calving to breeding and weaning (P < 0.01 and 0.01, respectively) and BCS at breeding (P < 0.01) quadratically decreased. There was a quadratic response (P = 0.03) in pregnancy rate to fat inclusion, maximizing at 150 g/d of added fat. Although fat inclusion tended to linearly decrease (P = 0.10) male birth weight, there were no differences (P ≥ 0.34) in progeny weaning weight or average daily gain from birth to weaning for either sex. Fat supplementation at 150 g/d optimized reproduction without negative impacts on pre-weaning progeny growth and profitability.

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