Brent Jones from South West Ontario Veterinary Services, Dietary Potato Starch: Does It Affect Intestinal Immunity?


There is a growing body of evidence that is  linking  the  interactions  between  diet, intestinal  microbiota,  and  the  pig’s immune  system.  These  interactions  have broad  implications  on  pig  health.  Prebiotics  are dietary compounds that can promote the growth of pig health friendly microbes in preference to disease causing  microbes.  Dietary  prebiotics,  such  as resistant (potato) starches are minimally digested by the  host  and  commensal  microbes  in  the  small intestine. Because of this they can make their way downstream  to  the  large  intestine  where  they  are available   to   the   microbes   as   accessible carbohydrates.

When  these  fermentable  carbohydrates  become depleted the large intestine bacteria often shift from utilizing  diet-derived  carbohydrates  to  harvesting host-derived sugars from the pig’s intestinal mucus layer. If the rate of utilization outpaces the rate of replenishment,  the  pig’s  immune  system “barrier function” can  be  compromised.  When  dietary carbohydrates  are  available  microbes  will  also ferment   the   carbohydrates   into   beneficial metabolites such as short-chain fatty acids (SCFAs). These SCFAs such as butyrate are consumed by the pigs intestinal cells as a source of fuel which then allows for increased secretion of protective mucus, pathogen   killing   antimicrobial   peptides   and immunoglobulin  A. In  this  study,  the  researchers fed the pigs either a diet amended with 5% resistant potato  starch  (RPS)  or  an  unamended  control  diet (CON).

The  researchers  discovered  that  RPS  in  the  diet intake increased the abundance of anaerobic Clostridia in feces and several tissues intestinal butyrate concentrations regulatory  T  cells  in  the  large  intestine  and imune  status  alterations  were  indicative  of enhanced mucosal defenses. regulatory T cells that positively correlated with butyrate    concentration,    luminal    IgA concentration,  expression  of  IL-6  and  DEF1B, and several mucosa-associated bacterial taxa.

Take Home Message

  • RPS   inclusion   in   feed   modulated   the microbiota  and  host  immune  status  through alterations  in  large  intestine  barrier  function and immunological tolerance
  • RPS  reduced  the  favourable  environment  for bacteria  such  as  Salmonella,  and  Escherichia species that utilize bacterial respiration rather than fermentation.
  • Because  there  was  no  specific  disease challenge  in  this  model  there  were  no differences in pathological lesions in this study but testing this finding in a disease challenge model would be a logical next step.

Submitted by Brent Jones, DVM

Ref: Trachsel J, Briggs C, Gabler NK, Allen HK, Loving CL.Dietary Resistant Potato Starch Alters Intestinal Microbial Communities and Their  Metabolites,  and Markers  of  Immune  Regulation  and  Barrier Function  in  Swine.Front  Immunol.  2019  Jun  19;10:1381.  doi: 10.3389/fimmu.2019.01381. eCollection 2019.


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