1,721,004 research outputs found
Fishmeal Supplementation During Gestation and Lactation Protects Offspring Against Maternal Simulated Infection Induced Programming
No full textAdverse uterine environments caused by stressors such as an infection during pregnancy can alter the programming of the fetus, increasing the risk of adulthood inflammatory disease. Supplementation with fishmeal (FM; rich in anti-inflammatory omega-3 polyunsaturated fatty acids; n-3 PUFAs) during pregnancy may help to reduce this risk. To test this hypothesis, 53 ewes were allocated to either a diet supplemented with FM or soybean meal (SM; rich in n-6 PUFAs), and on gestation day 135 (gd135) half the ewes from each dietary treatment were challenged with either 1.2 μg/kg lipopolysaccharide (LPS) to simulate a bacterial infection, or saline as a control (CON). The cortisol response of the offspring was assessed at weaning ± ACTH challenge, and during adulthood by LPS endotoxin challenge. Immune responsiveness of the adult offspring was assessed with a skin hypersensitivity test using antigens, ovalbumin (OVA) and candida albicans (CAA), and by measuring the OVA-specific serum antibody response. The FM+LPS treatment lambs had the greatest cortisol response compared to all other treatment groups during both weaning and endotoxin challenge. In contrast, the SM+LPS lambs had a greater cortisol response compared to the SM+CON treatment group during weaning + ACTH challenge. The SM+LPS offspring had the greatest hypersensitivity response to both OVA and CAA as well as the greatest serum IgG response to OVA compared to all other treatment groups. Lastly, the expression of hippocampal glucocorticoid and mineralcorticoid receptor genes (GR and MR) were shown to be different, with FM+LPS females having greater GR expression compared to SM+LPS females, while the reverse was true for MR. These data suggest that FM may help protect the offspring from immune system and HPAA programming during maternal infection. Future studies need to focus on the mechanisms behind these alterations.Ontario Ministry of Agriculture, Food and Rural AffairsOntario Sheep Marketing AgencyOntario Graduate ScholarshipUniversity of Guelp
An Investigation into the Use of Butyrate to Reduce Risk of Endotoxemia during Lethal Bacterial Lipopolysaccharide Challenge in Larval Zebrafish
No full textButyrate is a short-chain fatty acid with considerable benefits to gut health, and in recent years has been commonly used as an alternative to antimicrobials in agricultural animal production. In this thesis, we assessed the protective effects of sodium butyrate (NaB) on larval zebrafish during a lethal Pseudomonas aeruginosa lipopolysaccharide (LPS) challenge and elucidated potential protective mechanisms of action. Larval zebrafish were pre-treated with 3 concentrations of NaB for 24 hours at 72 hours post fertilization (hpf), and then immune challenged with 60 µg/mL of LPS at 96 hpf. Our results demonstrate that larval zebrafish exposed to 6000 µM NaB prior to a lethal LPS challenge experienced significantly increased survival, and exposure to 6000 µM NaB significantly down-regulated the pro-inflammatory cytokine tumor necrosis factor α (TNF-α). Findings from this thesis are consistent with the beneficial effects of NaB on other vertebrate species and support potential use of NaB in aquaculture.Natural Sciences and Engineering Research Council of Canad
In Vitro Toxicity Assessment of Mycotoxins Using Bovine Mammary Epithelial Cells and Their Remediation Using Yeast Cell Wall-Based Adsorbents
Get PDFFrequent occurrence of the mycotoxins deoxynivalenol (DON), enniatin B (ENB), beauvericin (BEA), ochratoxin A (OTA) and citrinin (CIT) in ruminant feed and feedstuff can be a potential threat to feed safety and ruminant health. Inadequate biodegradation of mycotoxins by rumen microflora following ingestion of mycotoxin-contaminated feeds by animals can lead to their circulatory transport to tissues such as mammary gland. Individual effects of these mycotoxins on barrier and innate immune functions of the bovine mammary epithelium were first investigated using a bovine mammary epithelial cell line (MAC-T) by measuring endpoints including cell viability, transepithelial electrical resistance (TEER), paracellular flux of FITC-40 kDa dextran and the expression of genes coding the tight junction (TJ) proteins zonula occludens-1, occludin and claudin 3, pattern recognition receptor toll-like receptor 4 (TLR4) and selected cytokines interleukin-6, tumor necrosis factor-α and transforming growth factor-β. The results indicated that all tested mycotoxins significantly decreased cell viability in a concentration-dependent manner. DON was more potent than BEA and ENB, whereas OTA was more potent than CIT. Tested mycotoxins differentially modulated TEER and FITC-dextran flux as well as mRNA expression of selected TJ proteins, pro- and anti-inflammatory cytokines and TLR4. Efficacy assessment of three yeast cell wall-based mycotoxin adsorbents namely, yeast cell wall, yeast cell wall extract and postbiotic yeast cell wall-based blend to mitigate the toxicity of DON, BEA, OTA and CIT was then carried out using an in vitro approach combining chemical-based assay and cell-based bioassay following the incubation conditions simulating the temperature and pH occurring in the gastrointestinal tract of dairy cattle. Adsorbent efficacy assessment indicated that Hill and Freundlich adsorption isotherm models were well-fitted into the LC-MS data; all tested adsorbents contributed to sequestering the tested mycotoxins to varying degrees and mitigating adverse effects of mycotoxins on MAC-T cells. The postbiotic yeast cell wall-based blend appeared to be the most efficacious overall. These findings support the hypothesis that the tested mycotoxins can disrupt barrier and innate immune homeostasis of bovine mammary epithelial cells, and that yeast cell wall-based adsorbents possess the capacity to adsorb selected mycotoxins.Natural Sciences and Engineering Research Council of CanadaAlltech Canada Inc
Immunological Effects of Yeast Prebiotic, Probiotic Yeast, Black Solider Fly Larvae Meal and Sodium Butyrate on Larvae and Adult Zebrafish
No full textFunctional ingredients like prebiotics, probiotics, insect meals, and short-chain fatty acids are used in aquaculture to enhance fish health and disease resistance. However, their immunomodulatory mechanisms are not well understood. This thesis investigates the effects of prebiotic yeast, probiotic yeast, black soldier fly larvae (BSFL), and sodium butyrate (NaB) on zebrafish, a model for production species like salmonids. A 63-day feeding trial was conducted with adult zebrafish, followed by immune challenges using Pseudomonas aeruginosa lipopolysaccharide (LPS) and live Flavobacterium psychrophilum. Gene expression analysis indicated that NaB had anti-inflammatory effects, while BSFL showed immunomodulatory effects through changes in pro-inflammatory gene expression. A secondary RNA-sequencing experiment on larval zebrafish treated with either 3000 or 6000 µM NaB followed by an LPS challenge revealed that LPS activated the innate immune response while NaB enhanced tissue regeneration and cell barrier integrity. Overall, BSFL and NaB demonstrated significant immunomodulatory effects related to inflammatory processes
Effect of microalgae or fish oil supplementation on nursery piglet health
No full textWeaning is a stressor that can negatively impact pig performance. Similarly, maternal stress, such as bacterial infection, may alter programming of the fetal hypothalamic-pituitary-adrenal axis and the immune system, ultimately affecting offspring performance and predisposing them to disease later in life. Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation of nursery pigs or sows may reduce stress and promote nursery pig health and growth. Fish oil (FO) is considered a major source of n-3 PUFA; however, microalgae (AL) may provide an alternative source of n-3 PUFA. The objectives of this thesis were to investigate the effects of AL and FO supplementation in nursery pig and sow diets on nursery pig growth, stress and immune responses. In our first study, piglets were fed low-quality protein diets supplemented with AL, FO, or a corn oil (CO) control. In our second study, sows were fed diets supplemented with AL, FO, or CO in late gestation, and were immune challenged with lipopolysaccharide (LPS) on gestation day 112 to simulate a bacterial infection; their offspring were then placed on high- or low-quality protein diets at weaning. In both trials, the piglet stress response was assessed using an LPS immune challenge, and fever, cortisol and cytokine responses were measured to assess the acute-phase response. The piglet acquired immune response was also assessed using a dermal hypersensitivity challenge with novel protein antigens ovalbumin (OVA) and Candida Albicans (CAA), as well as by measuring OVA- and CAA-specific antibody responses. Results from the first trial showed that neither AL, nor FO supplementation affected offspring growth, however, both supplements reduced the fever response following LPS challenge. The AL treatment also resulted in increased cytokine concentrations. Results from the second trial showed that concentrations of cytokines were not affected by maternal diet and LPS immune challenge, but were decreased in pigs fed a low-quality protein diet. Despite the lack of maternal effects on the serum cytokine response, changes in male offspring adrenal transcriptome suggest that maternal treatments can influence lipid metabolism, steroidogenesis and immune response in the offspring. In both trials, the acquired immune response was not affected by the experimental treatments
An Investigation into the Potential Use of 6-Gingerol to Combat Endotoxemia and Reduce Inflammation during Tissue Trauma in Larval Zebrafish
Get PDFFish farming facilities are rapidly intensifying their operations in order to meet the increased demand for aquaculture products worldwide. As a result, fish farming populations are exposed to increased stressors such as higher bacterial load and higher incidence of injury, leading to higher incidences of mortalities. Immunomodulators can improve an organism’s response to stress by augmenting the immune response via enhancement or inhibition. However, the use of immunomodulators is an emerging concept in the aquaculture industry, and therefore potential immunomodulators must be effectively assessed. The purpose of this thesis was to develop a comprehensive immune microbe-associated molecular pattern (MAMP) challenge using larval zebrafish as a model organism, utilize said immune challenge to assess the immunomodulatory efficacy of 6-gingerol, and assess whether 6-gingerol could also improve healing after tissue trauma.Natural Sciences and Engineering Research Council of Canad
The Impact of Pre-exposure to High Concentrations of Vitamin D3 on the Toxicity of a Bacterial Endotoxin in Zebrafish (Danio rerio) Larvae
Get PDFVitamin D3 (VD3) is an essential immunomodulatory nutrientfor fish, but it is toxic at high doses. This study aimed to examine interactions between VD3 and bacterial lipopolysaccharide (LPS) endotoxin using larval zebrafish (Danio rerio). Larvae were pre-exposed to VD3 at 72 hours post fertilization (hpf) and at 96 hpf the media was replaced with LPS solutions; survival was assessed at 120 hpf. Total RNA was extracted at 72 and 96 hpf to quantify expression of VD3-metabolizing enzymes and transcriptomic changes using quantitative PCR and RNA-sequencing, respectively. Pre-exposure to 5, 10 and 20 µg/mL VD3 significantly reduced survival to LPS challenge in a dose-dependent manner. Basal expression of cyp2r1, cyp27a1, cyp27b1, cyp3a65, and cyp11a1 was upregulated between 72 and 96 hpf. VD3 exposure upregulated cyp24a1 expression and downregulated cyp2r1, cyp27b1, and cyp3a65 expression. Transcriptomic analysis revealed differentially expressed genes involved in inflammation, stress, and cell death positively correlated with endotoxin chemosensitization.Natural Sciences and Engineering Research Council of Canad
The Immunological Impact of Selenium Supplementation in Ewes during the Late Gestation and Post-Partum Periods
Get PDFSelenium (Se) is an essential micronutrient required to support animal health. In areas of soil deficiencies, Se must be supplemented in the diet. The objectives of this study were to assess how supplementing ewes on a Se-deficient diet with organic (oSe) or inorganic (iSe) Se affected their Se status and immune responses. A sample size of n=110 Dorset-Rideau ewes were randomly allocated into four treatment groups to receive a daily supplement of 0.3 mg or 0.6 mg oSe, 0.3 mg iSe, or 0 mg Se from gestation day 110 to postpartum day 49. After trial day 40, both oSe groups had significantly higher serum Se concentrations than the iSe group, revealing its superior bioavailability. Immunization with ovalbumin antigen to assess the adaptive immune response and an intravenous injection of lipopolysaccharide to assess their acute-phase response, revealed that the Se-deficient diet during the trial did not adversely impact ewe immune function.Ontario Sheep FarmersOntario Ministry of Farming, Agriculture and Agribusiness and Ministry of Rural AffairsNatural Sciences and Engineering Research Council of Canad
Johne's Disease in Dairy Cattle: Validation of Genetic Markers and Assessment of Salivary Gland Transcriptome
No full textJohne’s disease (JD) is a severe production limiting disease in cattle caused by Mycobacterium avium susbp. paratuberculosis (MAP) infection. Issues associated with currently available JD diagnostic methods have prompted evaluation of new diagnostic techniques. While the genetic basis of MAP infection status is supported via identification of various candidate genes and single nucleotide polymorphisms (SNPs), their validation prior to inclusion in a selective breeding program for JD resistance is essential. The purposes of this thesis was to evaluate salivary mRNA biomarkers as a potential MAP exposure diagnostic tool, identify new SNPs and also validate previously reported JD SNPs, and validate the functional relevance of the candidate gene IL10RA using a gene edited IL10RA knockout (KO) mammary epithelial cell line (MAC-T cells).RNA-seq transcriptome profile analysis of mandibular and parotid salivary glands revealed differences in expression of some immunoregulatory and anti-microbial genes between MAP-exposed and control unchallenged cattle. Subject to their validation, the identified expressed genes could serve as potential salivary biomarkers of MAP exposure. Fine mapping of previously identified JD quantitative trait loci by our lab, by imputation to high density (HD) SNP genotypes, enabled identification of new SNPs associated with MAP infection status. Follow-up validation of previously reported JD SNPs was also undertaken by testing their association with sire estimated breeding value (EBV) for milk ELISA test scores. A total of 498 sires grouped as high or low EBV group were genotyped using a custom SNP panel comprised of 155 JD SNPs, and 5 of these SNPs were confirmed for their association with JD. Functional relevance of a JD candidate gene was investigated by creation of IL10RA KO MAC-T cells using CRISPR/cas9 gene editing approach. Stimulation of IL10RA KO cells with immunostimulants like MAP lysate+/- IL10, revealed the regulatory role of IL10RA through its ligand IL-10 during MAP lysate stimulation. The findings of this thesis have addressed some of the knowledge-gaps specific to JD diagnosis and control. They provide a future framework for validation of salivary biomarkers, validation of JD SNPs using different JD phenotypes, and characterizing the functional importance of other JD candidate genes by gene editing approach.2020-12-1
Assessment of Heat Stress Response of Peripheral Blood Mononuclear Cells (PBMCs) from Dairy Cows Previously Stress Phenotyped Using Bacterial Lipopolysaccharide (LPS) Endotoxin
No full textHeat stress is a growing concern to the livestock industry as temperatures continue to rise globally. Heat stress negatively impacts the productivity, health and welfare of livestock. LPS is detected in blood of heat stressed animals which contributes to systemic inflammatory response, that may compromise heat dissipation from the body during heat stress. We anticipate that animals resilient to LPS-induced stress will also be more resilient to heat stress if LPS contributes to heat stress pathology. Therefore, the purpose of this thesis was to investigate the effects of an in-vitro heat shock challenge on bovine peripheral blood monocular cells (PBMCs) isolated from high (HSR), middle (MSR), and low (LSR) stress responder dairy cows. These cows were identified as either LSR, MSR or HSR based on the peak cortisol response to an LPS challenge. Assessing PBMC function in these phenotyped animals could support future goals to genetically select cows with increased resilience to heat stress.Natural Sciences and Engineering Research Council of CanadaOntario Ministry of Farming, Agriculture and Agribusiness and Ministry of Rural Affair
- …
