Location: Diet, Genomics and Immunology Laboratory2012 Annual Report
1a. Objectives (from AD-416):
ARS is interested in determining the impact of dietary induced changes in intestinal microflora that affect inflammatory aspects of obesity. In-house research has demonstrated that the pig can be used to model changes in immunological and anti-inflammatory responses to diets that correspond to changes in bacteria in the gut. Feeding a conventional diet containing added levels of fructose, fat, and cholesterol (HF/HFr/HC) compared to a conventional diet increased aspects of the metabolic syndrome in juvenile Ossabaw and conventional pigs.
1b. Approach (from AD-416):
Fecal material from Ossabaw sows prior to weaning and their piglets pre- and post-weaning will be evaluated for changes in microbial populations and metabolomics. The analysis will provide a measure of robust changes in bacterial populations that result from dramatic changes in diet pre- and post weaning. Additional changes in bacterial populations will be evaluated following a comparative regimen of feeding a conventional diet compared to one with added HF/HFr/HC and detection of single copy genes for Bifidobacterium and Lactobacillus species measured by real time PCR along with other genera and species including Eubacteria, pan Bifidobacterium, pan Lactobacillus, Escherichia coli, Clostridium difficile, and Bacteriodes fragilis. Changes in innate and acquired immune response patterns in the local tissues and selected circulating markers in whole blood will be evaluated by gene expression, histology, and physiology. This information will be used by both ARS and the cooperator to jointly develop studies that focus on how major modifications of diet affect intestinal microbial populations associated with host change that affect intestinal health.
3. Progress Report:
Two studies have been completed that consider changes in intestinal bacterial populations in pigs fed a high energy/high fat diet and given a daily dose of probiotic bacteria from a commercial source that is used in human foods. Manuscripts are in preparation to describe changes in diet that alter the intestinal microbiome and are associated with differences in body weight, fat deposition, clinical measurements, and host gene expression in the intestine, liver, and adipose tissue. Another study was completed and data published on volatile organic compounds in intestinal contents that changed during a parasitic whipworm infection. These changes partially explain alterations in the local intestinal microbiome that contribute to local intestinal tissue pathology.