Presented at the 4th Microbiome R&D and Business Collaboration Forum: USA. To find out more, visit: www.global-engage.com Julian Trachsel from Iowa State University/USDA-ARS presents data that suggests raw potato starch may be an effective prebiotic to promote gut health and mitigate early life intestinal complications.

1. Raw potato starch changes the
butyrate-producing microbiota
and host immune responses in
pigs
Julian Trachsel, Cassidy Briggs, Crystal Loving, Heather Allen

2. • Food Safety and Enteric Pathogens Research Unit
1) Prevent foodborne illness such as Salmonella and E. coli (pre-harvest)
2) Find alternatives to antibiotics
• How can we maintain a safe (and profitable) food supply while
reducing medically important antibiotic use in our farming systems?
Motivations

3. Motivations
• Recent focus on young piglets, post weaning
• The most common time for antibiotic intervention, often prophylactic.
• Weaning is very stressful
• Massive dietary change
• Transport stress
• First contact with non-littermate pigs
• Transitional microbiota
• Less effective pathogen exclusion
• Critical window for training and modulation of the immune response

4. BUTYRATE
Transcriptional changes in
host epithelia
Mucus Secretion
Antimicrobial
Peptides
Tight Junction
proteins
Preferred colonocyte
energy source
pH reduction and pH
dependent
antimicrobial activity
Immunomodulatory Activity
Induction of Treg cells
CD4+ T-cell anergy
Reduced epithelial
sensitivity to IFN-γ
Reduced macrophage pro-
inflammatory mediators
Tolerance of the microbiota and reduced inflammation
Maintenance of Colonic Epithelial Barrier

6. Butyrate reduces oxygenation of the intestinal
epithelia
Pimonidazole staining (red) indicates hypoxia
Chavez et. al., Cell Host Microbe. 2016 Apr 13;19(4):443-54.

7. Mucosal pathogens benefit from community
disturbance
• Many pathogens do better with a little oxygen
• Salmonella
• E. coli
• Citrobacter
• Brachyspira
• Campylobacter
• Reduce epithelial oxygen potential to limit colonization?
• Some pathogens thrive during inflammation
• Salmonella

8. Modulating butyrate producing community as
a preventative intervention
• Young piglets do not have a well established butyrate-producing
community, or microbiota in general
• Maybe partially responsible to susceptibility to enteric pathogens,
(oxygenated epithelia, lack of competitive exclusion etc.)
• Can we speed the establishment of butyrate producers to help
improve resistance to proteobacteria or other pathogens?
• Selectively feed beneficial microbes
• Raw Potato Starch (RPS) prebiotic
• Resistant starch, escapes host digestion
• Highly fermentable in the hindgut

10. RPS alters cecal VFA profiles
p = 0.2 p = 0.05 p = 0.01

11. RPS changes the abundance of several genera
in the fecal microbiota

12. but gene amplicon: specific profiling of the
butyrate-producing community
• Developed a degenerate primer set to target the but gene
• Centrally important for butyrate production in the gut
• Trachsel et. al, AEM, 2016 Sep 9. pii: AEM.02307-16
• Very similar to 16S analysis, just specific to butyrate producers
• Allows us to see specifically which butyrate producing bacteria are
reacting to a particular treatment

13. RPS significantly changes the butyrate-producing
community

14. Lymphocytes from RPS treated pigs decrease
secretion of pro-inflammatory cytokines in
response to LPS stimulation
p = 0.004 p = 6.0e-4 p = 0.003

15. RPS fed pigs have altered T-cell populations in
their cecal tissues
p=5.8e-4 p=0.017 p=5.8e-4

16. RPS fed pigs have indications of a more robust
epithelial barrier
p = 0.1 p = 0.03 p = 0.03

17. Conclusions
• Inclusion of 5% raw potato starch in piglet diets causes significant
changes in the intestinal microbiota as well as the host immune
response to commensal microbes
• Increased butyrate production
• Improved tolerance of commensal microbes
• Improved epithelial barrier function
• Reduced niche for facultative anaerobes, Proteobacteria etc.
• Raw potato starch may help ease the stress of weaning and reduce
prophylactic antibiotic use