title: Changes in the gut microbiota of cloned and non-cloned control pigs during development of obesity: gut microbiota during development of obesity in cloned pigs.
abstract: BACKGROUND
  Obesity induced by a high-caloric diet has previously been associated with changes in the gut microbiota in mice and in humans. In this study, pigs were cloned to minimize genetic and biological variation among the animals with the aim of developing a controlled metabolomic model suitable for a diet-intervention study. Cloning of pigs may be an attractive way to reduce genetic influences when investigating the effect of diet and obesity on different physiological sites. The aim of this study was to assess and compare the changes in the composition of the gut microbiota of cloned vs. non-cloned pigs during development of obesity by a high-fat/high-caloric diet. Furthermore, we investigated the association between diet-induced obesity and the relative abundance of the phyla Firmicutes and Bacteroidetes in the fecal-microbiota. The fecal microbiota from obese cloned (n = 5) and non-cloned control pigs (n= 6) was investigated biweekly over a period of 136 days, by terminal restriction fragment length polymorphism (T-RFLP) and quantitative real time PCR (qPCR).
  
  
  RESULTS
  A positive correlation was observed between body-weight at endpoint and percent body-fat in cloned (r=0.9, P<0.0001) and in non-cloned control pigs (r=0.9, P<0.0001). Shannon Weaver and principal component analysis (PCA) of the terminal restriction fragments (T-RFs) revealed no differences in the bacterial composition or variability of the fecal microbiota between the cloned pigs or between cloned and non-cloned control pigs. Body-weight correlated positively with the relative abundance of Firmicutes in both cloned (r=0.37; P<0.02) and non cloned-control pigs (r=0.45; P<0.006), and negatively with the abundance of Bacteroidetes in cloned pigs (r=-0.33, P<0.04), but not in the non-cloned control pigs.
  
  
  CONCLUSIONS
  The cloned pigs did not have reduced inter-individual variation as compared to non-cloned pigs in regard to their gut microbiota in neither the obese nor the lean state. Diet-induced obesity was associated with an increase in the relative abundance of Firmicutes over time. Our results suggest that cloned pigs are not a more suitable animal model for gut microbiota-obesity related studies than non-cloned pigs. This study is the first to evaluate if cloned pigs provide a better animal model than conventional pigs in diet-intervention, obesity and gut microbiota research.
authors: National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, Frederiksberg C, 1870, Denmark.
authors: Rebecca
authors: R
authors: Pedersen
authors: Anders Daniel
authors: AD
authors: Andersen
authors: Lars
authors: L
authors: Mølbak
authors: Jan
authors: J
authors: Stagsted
authors: Mette
authors: M
authors: Boye
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000145:classification / Q000302:isolation & purification*; D058448:Biota; D019976:Cloning, Organism; D004269:DNA, Bacterial / Q000235:genetics; D059305:Diet, High-Fat; D005243:Feces / Q000382:microbiology*; D005260:Female; D006094:Gram-Positive Bacteria / Q000145:classification / Q000302:isolation & purification*; D051379:Mice; D009765:Obesity / Q000382:microbiology*; D012150:Polymorphism, Restriction Fragment Length; D060888:Real-Time Polymerase Chain Reaction; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial
references: Science. 2008 Jun 20;320(5883):1647-51
references: 18497261
references: Vet Microbiol. 2008 Apr 1;128(1-2):96-107
references: 17996403
references: Nature. 2006 Dec 21;444(7122):1022-3
references: 17183309
references: Obesity (Silver Spring). 2010 Jan;18(1):190-5
references: 19498350
references: Nature. 2009 Jan 22;457(7228):480-4
references: 19043404
references: Lett Appl Microbiol. 2008 Nov;47(5):367-73
references: 19146523
references: J Microbiol Methods. 2011 Sep;86(3):351-6
references: 21704084
references: Nutr Res Rev. 2010 Jun;23(1):4-22
references: 20500926
references: Cell. 2006 Feb 24;124(4):837-48
references: 16497592
references: BMC Microbiol. 2011 May 15;11:103
references: 21575148
references: Appl Environ Microbiol. 2002 Feb;68(2):673-90
references: 11823207
references: J Proteome Res. 2012 Jul 6;11(7):3573-80
references: 22612070
references: Comp Med. 2010 Aug;60(4):300-15
references: 20819380
references: ISME J. 2007 Jun;1(2):156-62
references: 18043625
references: Int J Obes (Lond). 2009 Jul;33(7):758-67
references: 19050675
references: Gut. 2010 Dec;59(12):1635-42
references: 20926643
references: BMC Physiol. 2011 Aug 22;11:14
references: 21859467
references: Br J Nutr. 2010 Sep;104(6):919-29
references: 20441670
references: J Appl Physiol (1985). 2011 Aug;111(2):573-86
references: 21596923
references: Nucleic Acids Res. 2001 Jan 1;29(1):173-4
references: 11125082
references: Gastroenterology. 2009 Nov;137(5):1716-24.e1-2
references: 19706296
references: J Pediatr Gastroenterol Nutr. 2011 Sep;53(3):303-9
references: 21865979
references: Proc Natl Acad Sci U S A. 2005 Aug 2;102(31):11070-5
references: 16033867
references: Cell Reprogram. 2012 Oct;14(5):407-17
references: 22928970
references: Int J Obes (Lond). 2008 Nov;32(11):1720-4
references: 18779823
references: J Med Microbiol. 2005 Dec;54(Pt 12):1239-1242
references: 16278440
references: Science. 2005 Jun 10;308(5728):1635-8
references: 15831718
references: Am J Clin Nutr. 2011 Jul;94(1):58-65
references: 21543530
references: Microb Ecol. 2007 May;53(4):562-70
references: 17406775