Source: LOUISIANA STATE UNIVERSITY submitted to NRP
EFFECTS OF DIETARY RESISTANT STARCH ON THE MICROBIOTA OF THE LARGE INTESTINE AND ASSOCIATED HEALTH BENEFITS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1005254
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Dec 11, 2014
Project End Date
Oct 31, 2018
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
LOUISIANA STATE UNIVERSITY
202 HIMES HALL
BATON ROUGE,LA 70803-0100
Performing Department
School of Human Ecology
Non Technical Summary
Resistant starch is a type of starch that is not digested in the small intestine and reaches the large intestine where it is fermented by the bacteria. Fermentation of resistant starch has resulted in many beneficial health effects in several species. In the current proposal, several studies will be perfrormed. The first study measures changes in the microbiota (bacteria in large intestine) in human subjects fed increasing amounts of resistant starch (0, 25, 50, and 75 g/ 2-week periods). It is anticipated that there will be differences in the changes reflecting subjects that respond or do not respond to feeding of resistant starch. In the second study, a type of obese and diabetic rat that robustly fermented dietary resistant starch, will also be tested for microbiota changes. In the third study, a combination of two antibiotics that do not leave the gastrointestinal tract and enter the blood stream, will be tested in rats to determine if they prevent the fermentation of resistant starch. In studies 4-6, three different types of elderly mice will be fed resistant starch to determine improvements in their health and also antibiotics will be used to prevent fermentation of resistant starch to determine if fermentation of resistant starch is required for health benefits of the resistant starch.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
70215101010100%
Goals / Objectives
The overall goal of our research with dietary resistant starch is to improve human health. Human studies investigating fermentable fibers have demonstrated that there are responders and non-responders apparently based on the ability or inability to change the microbiota of the large intestine to adequately ferment the fiber. Our research plan is to investigate the component phyla down to genera of the large intestine microbiota. These are taxonomic ranks in biological classification. The microbiota will be characterized in humans and rodent models. Other related variables associated with fermentation will also be measured and reported.The overall objective of this proposal is to investigate the effect of dietary resistant starch, a fermentable fiber, on the characteristics of the microbiota of the large intestine.The proposal is divided into six studies that may or may not encompass the full four years of this proposal. Other studies will evolve based on results of the initial studies and may be conducted within the four-year time frame.
Project Methods
Study 1 is a further analysis of fecal samples from humans previously fed increasing amounts of resistant starch in yogurts; 0, 25, and 50 g/dayeach over two-week periods. A breakfast-type bar was included with yogurts for feeding of 75 g/day of resistant starch. DNA from fecal samples has been previously extracted using a kit from MP Biomedical company and the extracts will be sent to the LSU Health Sciences Center Phylogenic Bacterial Analysis lab for amplification using primers forahypervariable region of the 16S ribosomal RNA gene followed by sequencing of the amplicons by synthesis using four different fluors for each of the four DNA bases.In study 2, the DNA extracts from Zucker Diabetic Fatty rats that were previously fed a diet containing resistant starch or control diet. The anlysis of the DNA extracts will be the same as described above for the DNA extracts of the human fecal samples.Studies 3-6 will employ standard American Institute of Nutrition 93 Mature semi-purified powdered diets for feeding of rats in study 2, and three types of elderly mice in studies 3-6. In study 2, Sprague Dawley rats will be purchased from Harlan Company. Black 6 elderly mice used in study 4 will be obtained from a National Institute of Aging colony maintained by Charles River Company. Interleukin 10 knockout mice used in study 5 will bepurchased fromJackson Labs. The glucagon-like receptor knockout mice used in study 6 are maintainedin a colony at the neighboring Pennington BiomedicalResearch Center.In study 3, the non-systemic regimen of neomycin , 0.5 g/L, and ampicillin, 1.0 g/L, will be deliverd to the rats in the drinking water for 4 weeks simultaneously with the feeding of resistant starch; and markers of fermentation will be measured to determine their effectiveness at knocking down fermentation of resistant starch.In studies 4-6, health effects of feeding resistant starch will be measured that include: changes in the microbiota, microbiota gene expression, a test of dexterity (ability to stay on a turning roto-rod), better mental function (maze testing), and measurement of pro-inflammatory markers. In these same studies, it will be determined if fermentation of resistant starch is necessary for beneficial health effects of resistant starch to be observed.

Progress 12/11/14 to 10/31/18

Outputs
Target Audience:The target audience includes readers of scientific journals. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project director attended the Nutrition 2018 meeting in Baltimore June 8-12 and attended several oral and poster presentations. How have the results been disseminated to communities of interest?Research results were published in journal articles. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Our group performed a second study using CD obese-prone (OP) and CD obese-resistant (OR) rats. Previously we reported the use of these same types of rats in a separate study in which we observed that the obese-prone rats robustly fermented resistant starch type 2 (RS2) as part of a low fat diet and obese-resistant rats were low fermenters. We had hypothesized that obese-resistant rats would have a healthier microbiota (gut bacteria), would ferment better, and that had accounted for their resistance to obesity when fed a high fat (HF) diet. Thus, our results were a surprise to us. These two types of rats, however, give scientists good models for humans because there are at least three journal article publications reporting good and poor fermenters of resistant starch. Our second study had as its major aim to try to improve the fermentation of the poorly fermenting rats and to reduce the fermentation of the good fermenters by transplanting cecal contents from the opposite type of rat. We also chose to use a HF diet as an additional tool to reduce the fermentation by the good fermenters, while theoretically not affecting the fermentation by the poor fermenters. Prior to the transplant, we compared three different methods for a knockdown of the rats' microbiota compared to water. This may be necessary in conventional organisms that are not germ free. The three methods as well as the water control were administered by gavage (a tube place through mouth to stomach attached to a syringe with liquid) and included the two antibiotics neomycin and ampicillin, vancomycin and merepenem, or MiraLAX® (colonoscopy clean out). The amounts of antibiotics used followed published studies, and the MiraLAX® dose was scaled down by body weight from the human recommendation for each dose and two doses were given. Antibiotic cocktails were given in a 1 ml volume for each of three days. The MiraLAX® and water control groups had a gavage of water. Before the third day all rats were fasted overnight so rats receiving MiraLAX® would be treated similar to people that are reported to have reduced gut bacteria after colonoscopy prep. On day three of potential knockdown of gut microbiota the MiraLAX® rats had two gavaged doses an hour apart, the two groups receiving antibiotics had one gavage of antibiotics and one of water, and the water control group had two water gavage doses. The overall plan of the study was to begin with 28 OP and 28 OR rats. After four weeks of feeding of a HF diet, four of each type of rat were euthanized for collection of cecal contents for later transplant with the cecal contents diluted 1 to 10 with 15% glycerol in phosphate buffered saline and stored at -80 degrees until use several days later. The remaining twenty-four rats of each type were assigned to one of the four types of knockdown described above. Fecal collections were made before and after knockdown treatments. Then after knockdown treatments all rats were fed a HFRS2 diet with 20% RS2 by weight of the diet and treated with cecal transplants for the opposite type of rats for three days of one gavage per day. The cecal contents were collected under aerobic conditions to test if gut facultative anaerobic and aero-tolerant (stay alive and then grow again when anaerobic conditions occur) bacteria will have an effect on the microbiota to change its ability to ferment dietary RS2. This is in line with three things: (1) the fact that aerobic collection and blending of feces for human fecal matter transplant are reported to successfully treat a blooming of Clostridium difficile after antibiotics treatment, (2) probiotic products that are considered effective for health are not maintained under anaerobic conditions, and (3) our use of non-sparged water for production of cecal contents encapsulated in pectin beads resulted in culture of species in genera Bifidobacteria that were apparently aero-tolerant. The results included successful knockdown of total bacteria in the four groups treated with antibiotics, but no knockdown with groups treated with MiraLAX® or water control. This result was different from our previous study with use of antibiotics in the rat drinking water that showed no decrease in total bacteria, but showed changes in the bacterial types. However, OP rats had greater fermentation than OR rats similar to our first study with these types of rats. The relative abundance of bacterial DNA is currently being analyzed by our research group. The study results indicate that either the microbiota of the OP and OR rats are either resistant to change or that anaerobes that may not have survived the collection process are needed to produce a change in microbiota composition for fermentation of RS2. Our group has recently practiced anaerobic collection technique for use in future studies with OP and OR rats.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Peterson CM, Beyl RA, Marlatt KL, Martin CK, Aryana KJ, Marco ML, Martin RJ, Keenan MJ, Ravussin E Effect of a 12 wk of resistant starch supplementation on cardiometabolic risk factors in adults with prediabetes: a randomized controlled trial. American Journal of Clinical Nutrition 2018 108:1-10
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Obanda D, Page R, Guice J, Raggio AM, Husseneder C, Marx B, Stout RW, Welsh DA, Taylor CM, Luo M, Blanchard EE, Bendiks Z, Coulon D, Keenan MJ. CD obesity-prone rats, but not obesity-resistant rats, robustly ferment resistant starch without increased weight or fat accretion. Obesity 2018 26:570-577. PMCID:PMC5826621
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Marlatt KL, White UA, Beyl RA, Peterson CM, Martin CK, Marco ML, Keenan MJ, Martin RJ, Aryana KJ, Ravussin E. Role of resistant starch on diabetes risk factors in people with prediabetes: design, conduct, and baseline results of the STARCH trial. Contemp Clin Trials. 2018;65:99-108.


Progress 10/01/16 to 09/30/17

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project director and 3 graduate students attended The Experimental Biology in Chicago, IL in April 2017 for presentation of research studies by the graduate students. Also, the project director and graduate studentsattended a variety of oral and poster presentations for professional development. Michael Keenan (PI) and 3 graduate students (Ryan Page, Diana Obanda, and Justin Guice) attended the annual Experimental Biology meeting in Chicago, IL April 22-26, 2017. The students participated in Research Interest Sections' poster competitions on Saturday April 22. Diana Obanda won first placefor the Obesity Research Interest Section for graduate students. All three students also gave minisymposia oral presentations during the meeting. How have the results been disseminated to communities of interest?Results were disseminated at the Experimental Biology meeting in Chicago, IL in April 2017 and 2 abstracts were published in FASEB Journal. Additionally results were published in two journal articles in 2017. What do you plan to do during the next reporting period to accomplish the goals?The plan is to continue investigating the effects of dietary resistant starch on the microbiota and the possible health benefits to the host organism. Results from several studies that were completed in the last couple of years were and will be written up for publication in 2018.

Impacts
What was accomplished under these goals? Our research group conducted a rat study using two related outbred strains of rats. The two strains were CD obese-prone (OP) and CD obese-resistant (OR) rats. These two rat strains were developed from breeding the heaviest Sprague Dawley rats and these strains are now housed at Charles River Company. Out of this developed rats that were not susceptible to increased weight and obesity on a high fat diet called OR, and rats that increased weight and body fat when fed a high fat diet that are called OP. The "CD" refers to a caesarian-derived step in the process. Our previous research demonstrated that the fermentation of high-amylose maize resistant starch (HAMRS) was reduced in Sprague Dawley rats with the feeding of a high fat diet. There has been research in which investigators developed their own obese-prone and obese-resistant rats (Sprague Dawley) or mice (C57Bl/6J) by feeding a high fat diet, but no research with feeding HAMRS to the outbred OP and OR rats. We designed a study to feed either a high fat or low fat diet to both OP and OR rats for 4 weeks designated phase 1. In phase 1, 10 OP and 10 OR rats were fed the low fat diet, and 22 OP and 22 OR rats were fed the high fat diet. At the end of phase 1, 4 OP and 4 OR rats were euthanized from both the low fat and high fat groups. For phase 2 of the study, 6 OP and 6 OR rats continued on the low fat diet for another 4 weeks. The remaining 18 OP and 18 OR rats from the high fat group in phase 1 were placed into 3 separate groups for each type of rat. One group continued on the high fat (HF) diet, a second was switched to a low fat (LF) diet, and the third was switched to a low fat diet with 20% by weight of diet as HAMRS (RS). Phase 2 was statistically analyzed as a 2 x 4 factorial with one independent variable being 2 rat types and the other being the 4 diet treatments - LFLF, HFHF, HFLF, and HFLFRS covering phases 1 and 2. Our aim was to determine which type of rat fermented RS better after the feeding of a high fat diet and if fermentation in OP and OR rats resulted in greater obesity because of energy harvest from the large intestine or less accretion of body fat that we had observed in other rat models. We anticipated that the OR rats would ferment RS better than OP. With the 2 x 4 factorial we had two main effects of rat type and diet, and one 2-way interaction of rat type x diet without statistical penalty. For comparisons beyond the factorial design, we used a Bonferoni correction by dividing the chosen alpha level (p<0.05) by the number of comparisons and, therefore, we did not make all possible 28 comparisons. A Tukey post hoc means comparison test of all 28 comparisons increases the type 2 error rate more than the Bonfroni correction for limited targeted comparisons. The main results from the study were that the OP rats robustly fermented RS and the OR rats were low fermenters. Neither rat type had reduced nor increased accretion of body fat as HFLFRS group compared to their respective HFLF control group. We came away with three important conclusions for the study. The first was that increased fermentation does not always translate to greater body weight and body fat. This goes against the prevailing theory that obese individuals have greater energy harvest and that is part of the cause of their obesity. The second was that the OP rats have a microbiota, even after the feeding of a high fat diet, which readily ferments RS. OP rats had increased amounts of the bacterial family S24-7 and the archaeon species M. smithii. This result was unexpected. Lastly, the OR rats should be a good model for humans that have been reported in several publications that poorly ferment RS. Future studies may investigate the effect of a transplant of the microbiota from the OP rat into the OR rat to possibly biotransform OR rats from low fermenters to better fermenters of RS.

Publications

  • Type: Other Status: Published Year Published: 2017 Citation: Letter to the Editor: Keenan MJ, Martin RJ, Robertson MD, Aryana KJ, Witwer R, Warshaw H. Misleading conclusions on effects of resistant starch due to inappropriate formulation of controls, inadequate statistical power, and anomalies in the in vitro methods. Am J Clin Nutr. 2017 May;105(5):1248-1249. doi: 10.3945/ajcn.116.147991. PubMed PMID: 28461512.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Carvajal-Aldaz DG, Guice JL, Page RC, Raggio AM, Martin RJ, Husseneder C, Durham HA, Geaghan J, Janes M, Gauthier T, Coulon D, Keenan MJ. Simultaneous delivery of antibiotics neomycin and ampicillin in drinking water inhibits fermentation of resistant starch in rats. Mol Nutr Food Res. 2017 Mar;61(3). doi: 10.1002/mnfr.201600609. Epub 2016 Dec 22. PubMed PMID: 27794202; PubMed Central PMCID: PMC5334145.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Goldsmith F, Guice J, Page R, Welsh DA, Taylor CM, Blanchard EE, Luo M, Raggio AM, Stout RW, Carvajal-Aldaz D, Gaither A, Pelkman C, Ye J, Martin RJ, Geaghan J, Durham HA, Coulon D, Keenan MJ. Obese ZDF rats fermented resistant starch with effects on gut microbiota but no reduction in abdominal fat. Mol Nutr Food Res. 2017 Jan;61(1). doi: 10.1002/mnfr.201501025. Epub 2016 Aug 11. PubMed PMID: 27234399; PubMed Central PMCID: PMC5324831.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Obanda D, Page R, Guice J, Kyereh E, Raggio A, Tuuri G, Husseneder C, Martin R, Marx B, Coulon D, Stout R, Keenan M. Obese prone CD rats robustly ferment resistant starch (RS) with no increased weight and fat accretion FASEB J April 2017 31:138.3.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Page R, Guice J, Carvajal-Aldaz D, Raggio A, Welsh D, Taylor C, Luop M, Blanchard E, Husseneder C, Tuuri G, Marx B, Stout R, Martin R, Bruce-Keller A, Coulon D, Keenan M. Antibiotics administration altered microbiota composition after knockdown, donor transplant and chow diet FASEB J April 2017 31:138.4.


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:The scientific community that attends the annual Experimental Biology meeting. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project director attended the Experimental Biology meeting in San Diego, CA in April, 2016 for presentation of research studies by his graduate students and to attend a variety of oral presentations and posters for professional development. How have the results been disseminated to communities of interest?Results of the project director's lab have been disseminated to fellow scientists at the Experimental Biology meeting in San Diego, CA in April 2016. What do you plan to do during the next reporting period to accomplish the goals?The plan is to continue investigating the effects of dietary resistant starch on the microbiota and the possible health benefits to the host organism. Several studies are ongoing that will be completed and data analyzed in 2017.

Impacts
What was accomplished under these goals? Our research group conducted two studies using antibiotics (ampicillin (1 g/L) and neomycin (0.5 g/L)) in the drinking water of rats. The purpose of the two studies was twofold: first to knockdown the microbiota (bacteria) in the GI tract and prevent fermentation of dietary resistant starch (prebiotic fermentable fiber) to determine if previously observed beneficial effects were the result of fermentation; and second, to possibly develop a rodent model that did not ferment resistant starch and would require a transplant of the microbiota for future fermentation. In the first study, rats were given the antibiotic treatment for 3.5 weeks and then the treatment was stopped, and the rats receiving antibiotics were split into two groups. One group received a transplant of cecal contents (microbiota) by gavage (insertion of blunt needle attached to a syringe into the stomach) from rats fed resistant starch and no antibiotics, while the other group received a water gavage of the same volume. To our surprise, both groups subsequently fermented dietary resistant starch well. Therefore, we moved on to the second study in which rats were given the antibiotic treatment simultaneously with the feeding of resistant starch. This approach in the second study was successful in knocking out the fermentation of dietary resistant starch. The two groups fed resistant starch with antibiotic treatment for 4 weeks had cecal contents pH greater than 8, which was the same as the negative control rats that were not fed resistant starch. The positive control rats fed resistant starch had a cecal contents pH of 6.05. Rats treated with antibiotics had reduced Bifidobacteria species, similar amounts of Bacteroides species compared to the positive control group, and numerically higher total amounts of bacteria in cecal contents using qPCR measurements of bacterial DNA. Total bacteria were numerically increased with antibiotics, thus demonstrating only a shift in bacterial taxa. Antibiotic treatment also resulted in decreased amounts of the short-chain fatty acids acetate and butyrate,but increased amounts of propionate as propionate is produced by Bacteroides species. Although the antibiotic treatment was used to successfully eliminate fermentation of dietary resistant starch, the empty cecum weights were similar to the positive control group; and the serum glucagon-like peptide 1 (GLP-1) hormone was very highly elevated with antibiotics. These are confounding side effects that interfere with interpretation of studies but may be reduced if the antibiotic treatment time is reduced. Our group has very recent preliminary data that gavage of these same antibiotics one time each for three days had a greater knockdown effect on total bacteria without increased weights for empty ceca or increased serum GLP-1. Another approach to determine the mechanism for beneficial effects of dietary resistant starch would be the use of germ-free rodents. However, their useis problematic because this model isnot free of confounding effects as ithas elevated amounts of GLP-1 andan immature immune system. This means that there is not a very clean method to knockout fermentation of resistant starch to demonstrate cause and effect for fermentation. Although short-term use of antibiotics did not result in confounding side effects, the results from our first study demonstrated that once antibiotic treatment was stopped fermentation recovers with the feeding of resistant starch. The latter is a very positive effect because of the nice recovery of bacteria that ferment resistant starch.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Goldsmith F, Guice J, Page R, Welsh DA, Taylor CM, Blanchard EE, Luo M, Raggio AM, Stout RW, Carvajal-Aldaz D, Gaither A, Pelkman C, Ye J, Martin RJ, Geaghan J, Durham HA, Coulon D, Keenan MJ (2016) Obese ZDF rats fermented resistant starch with effects on gut microbiota but no reduction in abdominal fat. Mol Nutr Food Res DOI:10.1002/mnfr.201550125.
  • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Yu-Hsin Hsieh, Courtney M Peterson, Anne Raggio, Michael Keenan, Roy J Martin, Eric Ravussin, Maria L Marco (2016) Impact of Different Fecal Processing Methods on Assessments of Bacterial Diversity in the Human Intestine. Frontiers in Microbiology Accepted 9-27-2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Martin RJ, Fahrmann J, Carvajal-Aldaz, Guice J, Page R, Raggio A, Coulon D, Stout R, Pelkman C, Marco ML, Keenan M. GC-TOF/MS-based Metabolomic Profiling of Goto-Kakizaki (GK) Rats: Comparison of Diets Enriched with Purified Resistant Starch or Resistant Starch in the Form of Whole-Grain Flour FASEB J April 2016 30:685.3
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Guice JL, Carvajal-Aldaz DG, Page RC, Raggio AM, Martin RJ, Husseneder C, Durham HA, Geaghan JP, Marco, ML, Janes M, Coulon D, Keenan MJ. Resistant starch (RS) fermentation is prevented by low potency antibiotics (AB) neomycin and ampicillin FASEB J April 2016 30:690.3
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Zheng J, Gao C, Raggio AM, Enright FM, Martin RJ, Janes ME, Greenway FL, Keenan MJ Gut microbiota in wild type Caenorhabditis elegans: Stimulation by media containing dietary fiber from Prowashonupana barley FASEB J April 2016 30:683.1


Progress 12/11/14 to 09/30/15

Outputs
Target Audience:Our research group presented some of our research results at the Experimental Biology meeting in Boston March 28-April 1. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project director attended the Experimental Biology meeting in Boston, MA, in March/April 2015 for presentation of research studies by his graduate students and to attend a variety of oral presentations and posters for professional development. How have the results been disseminated to communities of interest?Results of the project director's lab have been disseminated to fellow scientists at the Experimental Biology meeting in Boston, MA, in March/April 2015. The project director also gave a poster presentation reviewing research with high-amylose maize resistant starch type 2 at the USDA NIFA Project Directors' meeting in Chicago, IL, in July 2015. What do you plan to do during the next reporting period to accomplish the goals?The plan is to continue investigating the effects of dietary resistant starch on the microbiota and the possible health benefits to the host organism. Several studies are ongoing that will be completed and data analyzed in 2016.

Impacts
What was accomplished under these goals? For 2015 our research group received results from next generation sequencing of the microbiota in obese Zucker Diabetic Fatty (ZDF) rats (collaboration with the bacterial phylogeny lab at the LSU Health Sciences Center in New Orleans, LA) fed four diets with different products for its major ingredient: 1) a control isolated starch with no high amylose maize resistant starch type 2 (HAMRS2), 2) control with whole-grain low HAMRS2, 3) test group with isolated starch with high HAMRS2, and 4) test group with whole-grain high HAMRS2. We expected fairly dramatic differences for the microbiota in the cecal contents (first part of the large intestine) among groups because the obese ZDF rats demonstrated robust fermentation of HAMRS2, and there was greater fermentation in the group fed whole grain HAMRS2. The microbiota results confirmed our expectations as the Unifrac beta-diversity, both weighted (focuses on amounts of different types of taxa present) and unweighted (focuses on the types of taxa present) were both highly significant (p<0.0001). Use of principal coordinate (PC) analysis highlighted these significant differences. The data were mathematically compressed into three coordinates and differences were best demonstrated with graphics with PC1 vs. PC2. Along PC1 (x axis) the test groups of rats fed high HAMRS2 separated from the control groups. Then along PC2 (y axis) the groups fed the isolated starch products, low or high HAMRS2 separated from the groups fed the whole grain products, either low or high HAMRS2. Despite the robust fermentation and what we would argue was the generation of a "healthy" microbiota, the obese ZDF rats did not have a reduction in the accretion of abdominal cavity fat that normally accompanies feeding of high HAMRS2 in several other rodent models. The obese ZDF is a homozygous rat with two defective gene alleles for the leptin receptor and, thus, has defective leptin signaling. These results demonstrated that dietary treatments that usually are able to reduce obesity are ineffective at least in some forms of genetically-induced obesity and would require gene therapy for improvement of the obese state. The positive takeaway from this research was that the obese ZDF rats during the study were thought to be a rodent model that did not ferment HAMRS2 as there was no evidence of looser stools found in other rodent models with feeding of HAMRS2. Thus, further studies of the microbiota of this rat model are warranted to determine what bacterial types promote robust fermentation of HAMRS2 without apparent discomfort (loose stools). This study may lead to development of probiotic products that may in the future allow humans to consume the requirement of fiber comfortably and may lead to increased health benefits.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Keenan MJ, Marco ML, Ingram DK, Martin RJ. Improving healthspan via changes in gut microbiota and fermentation. Age 2015 Oct;37(5):98. doi: 10.1007/s11357-015-9817-6. Epub 2015 Sep 14.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Aryana KJ, Greenway FL, Dhurandhar NV, Tulley R, Finley JW, Keenan MJ, Martin RJ, Raggio AM, Pelkman C, Janik D, Olson D, Zheng J. (2015) A resistant starch enriched yogurt : fermentability, sensory characteristics, and a pilot study in children. Faculty of 1000. 4:139 (doi: 10.12688/f1000.6451.1).
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Gao C, Gao Z, Greenway FL, Burton JH, Johnson WD, Keenan MJ, Enright FM, Martin RJ, Chu Y, Zheng J. Oat consumption reduced intestinal fat deposition and improved healthspan in Caenorhabditis elegans model. Nutrition Research (2015) http://dx.doi.org/10.1016/j.nutres.2015.06.007.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Goldsmith F, Keenan MJ, Raggio AM, Ye X, Hao Z, Durham H, Geaghan J, Jia W, Martin RJ, Ye J (2015) Induction of energy expenditure by sitigliptin is dependent on GLP-1 receptor. Plos One. May 4, 2015:1-9.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Keenan MJ, Zhou J, Hegsted M, Pelkman C, Durham HA, Coulon DB, Martin RJ. (2015) Role of resistant starch in improving gut health, adiposity, and insulin resistance. Advances in Nutrition 6:198-205.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Zhou J, Martin RJ, Raggio AM, Shen L, McCutcheon, Keenan MJ. (2015) The importance of GLP-1 and PYY in resistant starchs effect on body fat in mice. Molecular Nutrition and Food Research. 0:1-4.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Guice J, Carvajal-Aldaz, Page R, Raggio A, Marco M, Durham H, Geaghan J, Pelkman C, Martin R, Coulon D, Keenan M. A comparison of moderate fat (MF) and high fat (HF) diets enriched with purified resistant starch or resistant starch in the form of whole grain flour in rats. FASEB Journal April 2015 29:380.6.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Carvajal-Aldaz D, Guice J, Page R, Raggio A, Coulon D, Martin R, Stout R, Durham H, Geaghan J, Pelkman C, Ye J, Keenan M. A comparison of diets enriched with purified resistant starch of resistant starch in the form of whole grain flour in Goto-Kakazaki (GK) rats. FASEB Journal April 2015 29:380.5.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Zheng J, Wang M, Gao C, Heymsfield S, Martin R, Keenan M, Finley J, Greenway F, Enright, F, Li Z. Pomegranate juice altered lifespan and intestinal fat deposition in ceanorhabditis elegans model organism. FASEB Journal April 2015 29:606.20.