Investigation of an ETEC challenge and supplementation of direct-fed microbials in weaned pigs

dc.contributor.advisor John F. Patience
dc.contributor.author Becker, Spenser
dc.contributor.department Animal Science
dc.date 2020-02-12T22:53:06.000
dc.date.accessioned 2020-06-30T03:19:54Z
dc.date.available 2020-06-30T03:19:54Z
dc.date.copyright Sun Dec 01 00:00:00 UTC 2019
dc.date.embargo 2001-01-01
dc.date.issued 2019-01-01
dc.description.abstract <p>Economic losses in the nursery phase of pork production can largely be attributed to the underdeveloped gastrointestinal tract (GIT) and immune system of weaned pigs, which greatly increases their susceptibility to potential pathogens. Enterotoxigenic Escherichia coli (ETEC) is a common enteric pathogen that results in secretory diarrhea and leads to reductions in growth performance and increases in mortality, morbidity, and treatment costs. Vaccinations and antibiotics have traditionally been used as means of prevent or mitigating ETEC infections; however, with the increase in antibiotic resistant pathogens and pressure from the consumer population, pork producers are in need of alternative strategies. Dietary inclusion of direct-fed microbials have been proposed as a potential dietary strategy to prevent or mitigate the negative effects associated with weaning and ETEC infections due to their suggested ability to exert beneficial effects on the host’s GIT, immune system, and microbial population. Nonetheless, having an understanding of how disease physiologically impacts the pig is essential to developing effective alternative dietary technologies to prevent or mitigate disease. Therefore, the objectives of this thesis were to characterize the impact of an ETEC challenge in weaned pigs on growth, intestinal function, immune response, and mucosal microbiota, and to evaluate the potential beneficial effects of Bacillus-based DFMs under normal physiological and ETEC challenge conditions.</p> <p>To achieve our objective, two experiments were conducted. The results of Experiment 1 (Chapter 2) revealed that Bacillus-based DFMs did not affect body weight or growth performance of healthy nursery pigs housed in a commercial-like environment compared to the control diet, which may be a result of contrasting effects of the DFM products and dietary ingredients, such as zinc oxide. Experiment 2 (Chapters 3 and 4) investigated the impact of an F18 ETEC challenge on growth performance, intestinal function, immune response, and mucosal microbiota of weaned pigs, as well as evaluated the potential protective effects of two Bacillus-based DFMs (DFM1 And DFM2). The ETEC challenge increased fecal scores, reduced rectal temperature, impaired intestinal barrier integrity, altered immune response, resulting in reduced growth performance during 10-d post-challenge period. The ETEC challenge also induced dysbiosis in the mucosa-associated microbiota by increasing the abundance of potentially pathogenic bacteria and reducing the abundance of beneficial microbes. Our results suggest that the supplementation of DFM2 may potentially alleviate negative impacts of an ETEC challenge by improving intestinal barrier integrity and reducing bacterial pathogen load in the GIT microbial population.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/etd/17644/
dc.identifier.articleid 8651
dc.identifier.contextkey 16524462
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/17644
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/31827
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/etd/17644/Becker_iastate_0097M_18155.pdf|||Fri Jan 14 21:26:44 UTC 2022
dc.subject.disciplines Agriculture
dc.subject.disciplines Animal Sciences
dc.subject.keywords Direct fed microbials
dc.subject.keywords E. coli
dc.subject.keywords immune response
dc.subject.keywords intestinal barrier
dc.subject.keywords microbiota
dc.subject.keywords weaned pigs
dc.title Investigation of an ETEC challenge and supplementation of direct-fed microbials in weaned pigs
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication 85ecce08-311a-441b-9c4d-ee2a3569506f
thesis.degree.discipline Animal Science
thesis.degree.level thesis
thesis.degree.name Master of Science
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