Search Results

1. Closs, Gary Antibiotic Independent Approaches to Control Salmonella and Campylobacter in Poultry

Doctor of Philosophy, The Ohio State University, 2021, Food Science and Technology

Salmonella and Campylobacter are leading bacterial agents both nationally and globally, making them high public health concerns. Both are significant important zoonotic pathogens commonly found in livestock. Poultry and poultry products are the most common sources of human infections. Infected poultry show little to no clinical signs, and risk the chance of entering the food system, potentially contaminating consumers. Direct links between the high load of bacteria in the chicken intestinal tract and the high contamination of poultry carcasses support the need for pre-harvest control. Previously, antibiotics were used to control bacterial infections and growth; but increasing occurrence of antibiotic resistant bacteria has caused laws and practices to shift. Targeting the control of foodborne pathogens in the pre-harvest stage can improve animal welfare and public health. Alternative treatment methods are needed to combat Salmonella and Campylobacter in production animals, improve antibiotic stewardship, and subsequently strengthen the economy. We discovered the antimicrobial efficacy of Lactobacillus acidophilus (LA), Lactobacillus rhamnosus GG (LGG), and Bifidobacterium animalis subsp. lactis (Bb12) in vitro. More importantly, we showed LGG significantly reduced Salmonella in the chicken cecum by 1.9 logs (P<0.001) at 10 days post infection. LGG was also able to inhibit the growth/ presence of other food safety significant Salmonella serovars in an agar well diffusion assay. Characterization of antibacterial activity of LGG revealed that although organic acids are present, the most crucial part of inhibition are the heat and protease stable peptides that were identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). After which, we tested the efficacy of Lactobacillus rhamnosus GG (LGG) derived small peptides (P1-NPSRQERR, P2- PDENK, and P4-MLNERVK) against Salmonella Typhimurium (ST) in chickens and examined their antibacterial effects a (open full item for complete abstract)

Committee: Gireesh Rajashekara (Advisor); Anastasia Vlasova (Committee Member); Melvin Pascall (Committee Member); Scott Kenney (Committee Member) Subjects: Food Science; Microbiology

2. LaValley, Antoinette Distribution of Substance P (SP), somatostatin (SOM), and methionine-enkephalin immunoreactivities in the spinal cord of the domestic fowl, Gallus domesticus /

Master of Science, The Ohio State University, 1980, Graduate School

Committee: Not Provided (Other) Subjects:

3. Kim, Tong Drug resistance and resistance transfer factor of escherichia coli isolated from ready-to-cook broilers /

Master of Science, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects:

4. Duff, Audrey Characterization of Serum Profile and Innate Immunity Biomarkers During Enteric Inflammation in Broiler Chickens

Doctor of Philosophy, The Ohio State University, 2021, Animal Sciences

Inflammation primarily functions to control microbial infection, tissue damage and mediate tissue repair but is energetically costly. Chronic inflammation in poultry can result in suppressed health and performance parameters including growth, feed intake, and worsened feed conversion ratio. Ten experiments were conducted to describe new methods for the characterization of inflammation in the gastrointestinal tract (GIT) of poultry to further explicate GIT immune responses and potentially elucidate therapeutic or prophylactic targets. In tissue, proinflammatory stimuli are detected by receptors on various leukocytes which induces cell activation, proinflammatory cascades, and secretion of acute phase proteins into the bloodstream. Three experiments were conducted to evaluate total serum protein (TP), serum protein electrophoresis (SPE), and immunofluorescent (IF) staining of CD205+ dendritic cell (DC) for effects of in ovo inoculations with Citrobacter freundii (CF) or mixed lactic acid bacteria (LAB) on serum protein profiles and migration of intestinal DC populations. In ovo inoculations were administered into the amnion of fertile eggs on embryonic d18, body weights (BW) were recorded on day of hatch (DOH) and d10 to calculate body weight gain (BWG), and serum and ileal samples were collected on d10. All TP and SPE data were statistically analyzed relative to a control group. A lack of significant differences in BWG across experiments implied that only mild, low-level inflammation was induced by bacterial inoculums. However, in ovo bacteria influenced β serum fractions (p < 0.05 or = 0.07) in all experiments. Significant fluctuations within the β fraction indicate corresponding β fraction acute phase proteins may be useful markers in assessing bacterial infection. No CD205+ DC were detected in ileal samples which suggested that DC are not present or undetectable in this region in young chickens at 10 days. A lack of significant differences in other SPE fractions m (open full item for complete abstract)

Committee: Lisa Bielke (Advisor); Benjamin Enger (Committee Member); Thaddeus Ezeji (Committee Member); Ramesh Selvaraj (Committee Member) Subjects: Animal Sciences

5. Kathayat, Dipak Discovery of Novel Antibacterial Agents against Avian Pathogenic Escherichia coli (APEC): Identification of Molecular Targets, Assessing Impact on Gut Microbiome and Evaluating Potential as Antibiotic Adjuvants

Doctor of Philosophy, The Ohio State University, 2021, Comparative and Veterinary Medicine

Avian pathogenic E. coli (APEC), an extra-intestinal pathogenic E. coli (ExPEC), is one of the most common bacterial pathogens affecting poultry, including broilers, layers, breeders, turkeys and many other avian species. It causes high morbidity and mortality (up to 20%), decrease in production and increase in condemnation of carcasses (up to 43%) during slaughter, thus resulting in substantial economic losses to the poultry industry worldwide. Recent reports have suggested APEC as a source of human extra-intestinal infections, including urinary tract infections and sometimes meningitis. Further, APEC is also considered as a source of antibiotic resistance genes (ARGs) to human pathogens. Therefore, APEC is a pathogen of significant importance to both animal and human health. Currently, antibiotics are commonly used to control APEC infections; however, the increasing emergence of resistance to antibiotics and FDA (Food and Drug Administration) restrictions on using antibiotics in food-producing animals necessitate the development of new and effective antibacterials that can circumvent the resistance problem. Antibacterials targeting the outer membrane (OM) of bacteria can evade the problem of resistance in Gram-negative bacteria such as APEC. To this end, we discovered and evaluated small molecule (SM) growth inhibitors (GIs) and antimicrobial peptides (AMPs) affecting OM of APEC. We uncovered their antibacterial targets in the OM of APEC and assessed their impact on gut microbiome. We further demonstrated the potential of GIs as adjuvants to current antibiotics, including one of the last-resort antibiotics, colistin. A total of 11 GIs (GI1 – GI11) with bactericidal activity against APEC were identified through high throughput screening of pre-selected enriched small molecule library. Eight GIs that were effective and showed low toxicity in vitro in cultured epithelial and macrophage cells, red blood cells, and in vivo in wax moth (Galleria mellonella) larva mode (open full item for complete abstract)

Committee: Gireesh Rajashekara (Advisor); James Fuchs (Committee Member); Vlasova Anastasia (Committee Member); Hale Vanessa (Committee Member) Subjects: Animal Diseases; Bioinformatics; Microbiology; Molecular Biology; Molecules; Pharmaceuticals; Therapy

6. Griffin, Jacqueline Growth and Development of Modern Commercial Broiler Chickens Under Nutritional Influences.

Doctor of Philosophy, The Ohio State University, 2017, Animal Sciences

The overarching objective of the current research was to investigate morphological (growth) and biochemical (transcription) events underlying skeletal muscle growth and developmental in an ontogeny study using the P. major breast muscle of broiler chickens, from days 2 through 46. Another main objective was to use this time course approach to investigate growth/age dependent nutritional influences, using 3 dietary treatments; a control and two treatment groups containing differential decreases in percent digestible amino acid (NC1 -5% and NC2 -10%). This approach allowed the current research to address a wide-range of diversely relevant research areas, pertaining to both fundamental biology and industry implications in raising broiler chickens for the production of meat. Through quantitative gene transcriptional analysis we were able to investigate the transcriptional events underlying post-hatch skeletal muscle growth and development. Of particular interest was the temporal transcription of developmental MyHC isoforms, as the functional diversity driving their transitions remains unknown. In an effort to further our knowledge in trying to understand their functional diversity, we characterized their temporal transcription patterns under differential dietary treatments during post-hatch growth period using the P. major breast muscle. From which, we report an unexpected post-hatch increase in the transcription of embryonic MyHC isoform, Cemb3. For which, cemb3 transcription was markedly higher in the control diet. Alternatively, the second MyHC isoform for which dietary differences were observed, Cadult, showed the opposite transcription pattern, where an increase in transcription coincided with a further decrease in digestible amino acid levels (Control < NC1 < NC2). The overarching goal of maximizing growth in broiler chickens, for the production of meat, has perpetuated two areas of research that remain a central area of interest in both industry and academ (open full item for complete abstract)

Committee: Michael Lilburn PhD (Advisor); Macdonald Wick PhD (Committee Member); William Pope PhD (Committee Member); Christine Alvarado PhD (Committee Member) Subjects: Animal Sciences; Morphology