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Study Of Three Potential Variables That May Impact The Maximum Shear Force And Shear Variation During The Growth And Transport Of Mixed Sex Broilers Grown In Commercial Poultry Houses, Mark Christie

Graduate Theses and Dissertations

Temperature conditions during the transportation to the processing facility of commercial broilers have a direct impact on the meat texture, specifically maximum shear force and shear variation of cooked breast meat. Analysis of a calendar year of flock data (N=346), reveals that the largest impact of transport conditions, specifically temperature, is on the standard deviation of the flocks range of cooked shear values. The optimal transport temperature that yields broiler breast meat with average flock minimum shear and standard deviation values is approximately 60°F. The shear values for flocks at or near 60°F are on average 1 kg less than …

The Effects Of Perceived Predation Threat On Stress Response And Memory In Birds, Chlöe S. N. Carter

Electronic Thesis and Dissertation Repository

This study examined how perception of predator cues, across three sensory modalities, affects physiology and behaviour of songbirds. I hypothesized that the perception of predator threat would elicit physiological and behavioural responses in both acute and chronic exposure conditions. My first study examined the responses of wild-caught black-capped chickadees (Poecile atricapillus) and house sparrows (Passer domesticus), as well as lab-bred zebra finches (Taeniopygia guttata), to acute predation cue exposure by coding video recorded behaviour and corticosterone analysis. My second study examined changes in black-capped chickadees’ foraging behaviour and memory retention after chronic exposure to …

Synaptic Correlates For Stress Sensitization, Julia Kj Sunstrum

Electronic Thesis and Dissertation Repository

The stress response is essential for survival, but it can be detrimental when persistently activated during chronic stress. Therefore, the magnitude of the stress response must be finely-tuned in order to be adaptive. Indeed, an animal’s stress response system normally undergoes habituation that decreases responses to a repeated, familiar stressor. Importantly, the same animal still responds normally, or even becomes sensitized, to an unfamiliar (novel) stressor. This indicates that chronic stress simultaneously induces two opposing types of plasticity, one that underlies habituated responses and another that drives sensitized responses. The activation of the hypothalamic-pituitary-adrenal (HPA) axis — a hallmark of …

Evaluation Of Neurobiological Risk Factors For Alcohol Consumption; Convergent Evidence For Predispositional Effects Of Brain Volume, David Baranger

Arts & Sciences Electronic Theses and Dissertations

Alcohol is one of the most widely used psychoactive substances and accounts for 5% of global disease burden. The goal of the present work is to help advance efforts to both identify prognostic markers of risk, and to understand the mechanisms by which alcohol consumption impacts health. Early life stress is one of the strongest predictors of mental illness, including alcohol dependence, and has been hypothesized to impact risk via modulation of striatal reward functions and reward learning. Studies examined the effect of stress on reward learning and processing, and tested for moderation by genetic and environmental risk. Results were …

Hpa Axis Genetic Variation And Life Stress Influences On Functional Connectivity In Resting State Networks, Tara Ann Miskovich

Theses and Dissertations

Stressful or traumatic experiences are a key risk factor for developing psychopathology, primarily through the impact that chronic stress has on hypothalamic-pituitary-adrenal (HPA) axis functioning. The HPA axis regulates the stress response but can become dysregulated with chronic activation and impact brain functioning. In addition to environmental stressors, genetic variation in genes in the HPA axis appear to influence HPA axis functioning and is also related to disruption in brain functioning, particularly in the context of high life stress. The current study focused on examining potential mechanisms through which trauma and stress interacts with HPA axis genes to impact key …

Dietary Inclusion Of Enriched Chicken Bone Broth Prevents Trigeminal Sensitization Meditated By Early Life Stress, Orion Peterson

MSU Graduate Theses

Early life stress is considered a risk factor for development of migraine, which is a prevalent painful neurological disorder involving sensitization and activation of trigeminal neurons, and irritable bowel syndrome, a condition often comorbid with chronic migraine. The focus of my study was to determine the effects of early life stress and dietary inclusion of enriched chicken bone broth on trigeminal nociceptor sensitization and the gut microbiota. Adult Sprague-Dawley male “sender” rats subjected to primary traumatic stress were placed next to breeding or pregnant female rats that served as “receiver” rats (secondary traumatic stress) and in proximity to the offspring …

Genomic Approaches To Identify Important Traits In Avian Species, Bhuwan Khatri

Graduate Theses and Dissertations

This dissertation focusses on identifying different molecular markers that have impact on overall poultry production. Chapter one reviews microRNA (miRNA), copy number variation (CNV) and single nucleotide polymorphism (SNP) as markers suggested in different avian species by various studies. It reviews modern genomic approaches that are employed for next generation sequencing data analysis and verification.

Chapter two seeks to identify and validate the muscle specific miRNAs in the breast muscle of modern broilers and its foundational chicken line. Small RNA sequencing was performed to identify differentially expressed mature miRNAs in the breast muscles of these two chicken lines. Results showed …

Dissecting The Molecular Mechanism Of Early Tumor Dissemination In Non-Small Cell Lung Cancer, Xingtong Liu

Dissertations & Theses (Open Access)

Lung cancer is the most common cause of cancer related death in the United States and worldwide. It has been shown that 30%-55% of patients with early stages of non-small cell lung cancer (NSCLC) developed and died of recurrence after curative resection, suggesting that tumor cell dissemination occurred early in those patients before surgery. However, molecular evidence, underline mechanisms and risk factors for the NSCLC relapse remain largely unknown. Addressing these questions will be critical for the development of strategies to stratify the risk of recurrence and approaches to reduce these risks. My thesis focused on dissecting the molecular basis …

Impact Of An Exercise Program On Stress, Fatigue, And Quality Of Life For Individuals Living With Primary Immunodeficiency Disease, Kerri Sowers

Department of Physical Therapy Student Theses, Dissertations and Capstones

Background: There are over 300 Primary Immunodeficiency diseases (PID) that are a result of a genetic or idiopathic dysfunction of any aspect of the immune system. These conditions result in a higher frequency of infections, autoimmune conditions, or malignancies. Moderate intensity exercise is thought to help the immune system, while high intensity exercise may have a negative impact on immune function. The impact of exercise on individuals with an impaired immune system due to PID is not yet understood. Purpose: The purpose of this study was to investigate whether a low to moderate intensity exercise program would have an effect …

Factors Affecting Disordered Eating Among College Freshmen Upon Entering College, Libby Micaela Moser

Graduate Research Theses & Dissertations

Purpose: There is a gap in literature on disordered eating among college freshmen since 2011. Research has shown that disordered eating manifests itself during adolescence and is likely to transcend into adulthood1,7,8,9,14,15. The freshmen year in college is likely to be challenging for many students. During this time, they may develop disordered eating or perpetuate an existing condition3,4,14,15. This research study investigated the prevalence of disordered eating among college freshmen and factors that may impact this development. A comparison of prior history of disordered eating was also examined.

Methods: A cross-sectional survey study was conducted on college freshmen at Northern …

Detection Of Local Steroidogenic Enzyme Gene Expression In Brown Anoles, Ada Spahija

Honors Program Theses

The endocrine system in vertebrates responds to stress by releasing steroid hormones, mainly glucocorticoids (GC), which increase blood glucose levels to supply key organs and muscles with energy needed for survival. Steroid hormones are synthesized via an enzymatic pathway that converts cholesterol into either GCs, androgens, or estrogens in a step-wise manner. The adrenal cortex is known to produce GCs, but evidence suggests that individual organs can also produce steroid hormones de novo in response to stress. This study aims to quantify gene expression of four steroidogenic enzymes, encoded by CYP19A1, CYP17A1, StAR, and HSD17ß3 genes, via qRT-PCR to determine …

Single Men's Experiences Of Coping With Financial Stress, Heath Downes

Walden Dissertations and Doctoral Studies

Experiencing financial hardship is stressful and can lead to the development of psychological symptoms, including depression and anxiety. Although researchers have examined the broad categories of coping strategies that people employ when faced with financial hardship, little is known about the experiences of single men who were able to navigate stressful times without developing anxiety or anxiety-like symptoms. The purpose of this phenomenological study was to explore the successful coping experiences of single men with financial hardship (e.g., loss of job, home, finances). Bonanno's theory of resilience provided the framework for the study. Data were collected from interviews with 12 …

Endocrine Responses To Repeated Adrenocorticotropic Hormone Administration In Free-Ranging Elephant, Molly Mccormley

University of the Pacific Theses and Dissertations

Understanding the physiological response of marine mammals to anthropogenic stressors can inform marine ecosystem conservation strategies. Stress stimulates release of glucocorticoid (GC) hormones, which increase energy substrate availability while suppressing energy-intensive processes. Exposure to repeated stressors can potentially affect an animal’s ability to respond to and recover from subsequent challenges. To assess the endocrine response of a marine mammal to repeated stressors, we administered adrenocorticotropic hormone (ACTH) to free-ranging juvenile northern elephant seals (Mirounga angustirostris; n=7) once daily for four days. ACTH administration induced significant, but transient (<24 h) elevation in circulating cortisol levels (p < 0.0001). These increases did not vary in magnitude between the first ACTH challenge on day 1 and the last challenge on day 4. In contrast, aldosterone levels remained elevated above baseline for at least 24 hours after each ACTH injection (p < 0.001), and responses were greater on day 4 than day 1 (p < 0.01). Total triiodothyronine (tT3) levels were decreased on day 4 relative to day 1 (p < 0.01), while reverse triiodothyronine (rT3) concentrations increased relative to baseline on days 1 and 4 (p < 0.001) in response to ACTH, indicating a suppression of thyroid hormone secretion. There was no effect of ACTH on the sex steroid dehydroepiandrosterone (DHEA). These results suggest that elephant seals are able to mount adrenal responses to multiple ACTH challenges. However, repeated stress results in facilitation of aldosterone secretion and suppression of tT3, which may impact osmoregulation and metabolism. We propose that aldosterone and tT3 are informative additional indicators of repeated stress in marine mammals.