Key aims and expertise
To determine an effective strategy to reduce rotavirus infections in pigs. To better understand the relationship between gut microbiota function and health in monogastric species.
Expertise: Virology, cell biology microbial ecology, hind gut fermentation, bioinformatics, immunology, nutrition, gut health, transcriptomics
Current projects
Interventions in porcine rotavirus infection.
Rotavirus infections have significant impact on the morbidity and mortality of pigs in production world-wide. The focus of our work is to develop strategies for prevention of transmission of rotavirus transmission on farm. Given rotavirus is transmitted faecal-orally we have tested cleaning and disinfection regimes for their ability to lower enteric transmission on farm isolation and are developing vaccine candidates.
Analysis of Microbial Ecology of the Monogastric Gastrointestional Tract.
The intestinal tract of monogastric species is inhabited by dense populations of bacteria rich in species diversity. The bacterial inhabitants of the gut exist in a complex association with the host and the surrounding microorganisms. Using the pig as a model monogastric species, our group studies the shifts in bacterial community structure that can accompany dietary change or changes in host physiology and whether such shifts have the potential to affect host wellbeing. When changes in bacterial community do have a detrimental impact on health we seek to identify preventative measures through non-pharmaceutical, dietary intervention.
Determination of Host-Cell response to weaning stress in the pig.
Weaning of pigs from their mothers (sows) causes a significant stress, as pigs adjust to new environment and change in diet. As a result newly weaned pigs suffer from diarrheal disease and fail to grow for several days a phenomenon known as the post-weaning growth check. Given weaning pigs display characteristic phenotypes of stress- related bowel dysfunction, similar to other monogastric species, we can then study the process itself as a model, as well as intervention strategies. We have verified a four pig wean model, and are currently determining the effect of intervention by supplementing pigs using the probiotic Saccharomyces boulardii , as well as investigating host gene expression changes in gastrointestional and brain tissue using transcriptomics.
Understanding the enteric virome in shaping the microbiota of the weaning pig.
Introduction:
The microbiome contains 1000s of microbial species. The microbiota contributes to gut function including: protection against infection, metabolism, enterocyte health and the maintenance of innate immunity. Weaning of pigs from their mothers induces changes in the microbiome of the pig and other species that reduces diversity and limits function. Bacterial species exhibit shifts in relative abundance that result in changes in functionality. For the pig weaning can cause dysbiosis, increasing disease susceptibility and reducing key contributions to gut health. While some changes can be explained by the loss of mothers’ milk or change in diet, others cannot leaving roles for microbial competition and succession under the influence of bacteriophages or eukaryotic viruses.
Understanding bacteriophage control of the bacterial microbiome:
Significant changes occur in the structure of microbiome at weaning. What effect of the virome has on post weaning changes is unknown but has been proposed as a model for human enteropathy and bacteriophage treatment (http://gcgh.grandchallenges.org/grant/phage-therapy-weaned-piglet-model-enteropathy). We need to better understand the role of bacteriophage (lytic and lysogenic) in the bacterial microbiome. There is mounting evidence that phage provide microbiota with advantage genes in times of stress, as the case for antibiotic exposure and subsequent selection for antibiotic resistance genes, which are carried with phage and utilized following antibiotic exposure. Antibiotic treatment expands the resistance reservoir and ecological network of the phage metagenome. Since dysbiosis also occurs during weaning it seems likely that bacteriophage also influence the effectiveness of the microbiota transferred at that time. To investigate this we will isolate grow and spike (by drench) enteric phage into the weaning pig and compare to mock treated control. We will then compare the resultant microbiome between phage treated and mock treated pigs.
Understanding the Eukaryotic virome control of the bacterial microbiome
With the advent of metagenomic technology it is possible to characterize the virome of healthy pigs, which contain a multitude of viruses. Nucleotide sequences have identified a few of these, for example, Calicivirus, Picornavirus Parvovirus in the faecal virome; Coronavirus, Astrovirus and Circovirus in gut tissue. Additional to this we (and others) have recently found PERV (Porcine endogenous retrovirus) expression within colonic tissue and we have also identified a novel pestivirus expressed in colonic tissue. All of these viruses will impact immunological responses and cell signalling such as those leading to localised inflammation, and also the makeup of the microbiome. This is exemplified by recent reports of Coronavirus (PED) infection, which drastically changed the microbiome of pigs. To characterise the effect of these viruses on weaning pig we will attempt to grow and characterise the enteric virome using specialized colonic cells, deficient for their ability to respond to interferon. Spiking experiment similar to the ones described for phage will delineate the role of eukaryotic viruses on the microbiome of the weaning pig.
Significant Results
Cleaning and Disinfection:
Instructional video for pig industry: Watch the video in YouTube
Peer reviewed paper on Cleaning and disinfection regimes.
Hancox L., Le Bon, M., Dodd C.R. and Mellits K.H. (2013) Inclusion of detergent in a cleaning regime and effect on microbial load in livestock housing Vet Record 173 (7):167
Gut Health
Saccharomyces cerevisiae boulardii I-1079 and Bactocell ( Pediococcus acidilactici MA 18/5M) has a positive effect on the feed conversion ratio of newly weaned pigs
Le Bon M., Davies, H.E., Glynn C., Thompson C., Madden M., Wiseman J., Dodd, C.E.R, Hurdidge L., Payne, G., Le Treut Y., Craigon J., Tötemeyer, S. and Mellits, K.H. (2010) Influence of probiotics on gut health of the weaned pigLivestock Science 133, 179-81