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Title: An in vitro and in vivo assessment of Lactobacillus plantarum and lactulose as an intervention strategy against S. Typhimurium in pigs
Author: Tchórzewska, Monika Anna
Awarding Body: Royal Holloway, University of London
Current Institution: Royal Holloway, University of London
Date of Award: 2013
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S. Typhiumrium is a ubiquitous zoonotic pathogen, which remains a recognised human health risk factor in the food production chain. Following the withdrawal of antimicrobial growth promoters in animal feeds in the European Union, the enhancement of the host's resistance to enteropathogens by alternative control strategies has become essential. Probiotics are classified as live microbial feed supplements; often members of the normal flora and have been shown to improve gut health and further act as competitors against foodbome pathogens. Prebiotics are 000- digestable in the upper gut, however fermented in the large intestine carbohydrates aimed to selectively stimulate beneficial bacteria and therefore selectively modulate gut microbiota. Probiotics, prebiotic have been reported as successful in conferring protection against many pathogens. Therefore the aim of this project was the construction of an effective synbiotic combination of pre and probiotic that can be employed to control Salmonella colonisation in pigs. The results demonstrated that lactulose promoted the growth of L. plantarom in the pure culture and in ferrnentations with the complex porcine microflora, resulting in an increase of short chain fatty acid (SCFA) concentrations. The presence of L. plantarum cell-free supematant (CFS) conferred a strong inhibitory activity against S. Typhimurium growth. Moreover, L. plantarum together with the CFS reduced S. Typhimurium adherence and invasion to porcine epithelial cells. Inclusion of L. plantarum and lactulose in a batch culture system resulted in the overaU gradual decrease in Salmonella numbers as evaluated by fluorescent in situ hybridisation (FISH), which was correlated with the increases in SCFA. Finally, an in vivo trial was undertaken using a pig infection model. The results generated from this in vivo study in pigs, confirmed the superior effect of the probiotic candidate L. plantarom in combination with lactulose in comparison to probiotic or prebiotic alone. Together with the higher lactobacilli counts in the synbiotic feed group, a reduced frequency of Salmonella shedding was observed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available