Feeding resistant starch affects fecal and cecal microflora and short-chain fatty acids in rats.
The effects of different forms of resistant potato starch (RS) on the major microbial population groups and short-chain fatty acids (SCFA) in the cecum and feces of rats were studied over a 5-mo feeding period. Thirty 8-wk-old male Wistar rats, averaging 210 g initial body weight, were adapted for 7 d to a balanced basal diet containing 60% waxy maize starch devoid of any RS. On d 8, three groups of 10 rats each were fed diets containing the following forms of starch: 1) rapidly digestible waxy maize starch (basal diet), 2) a mixture of 83.3% waxy maize starch and 16.7% native granular potato starch (RS 1), or 3) a mixture of 33.3% waxy maize starch and 66.7% modified potato starch (RS 2). The final RS content in RS 1 and RS 2 was 10%. Fecal samples were collected at d 8 and 1, 3, and 5 mo after the start of the experiment. Cecal contents were taken after 5 mo. The colony counts of microbial groups did not vary with time in the control or the RS 1 group (P > .05). Only the number of Bacteroides/fusobacteria decreased between mo 1 and 5 in rats fed RS 1 (P < .05). The RS 2 diet led to a significant increase in total culturable bacteria, lactobacilli, streptococci, and enterobacteria between mo 1 and 5. The RS 1 and RS 2 diets stimulated the growth of bifidobacteria. Cecal numbers of lactobacilli, streptococci, and enterobacteria were higher in rats fed RS 2 than in rats fed RS 1 or control diet (P < .05). Lactobacillus cellobiosus occurred only in rats fed RS 1 or RS 2. Acetate increased in mo 3 compared with d 8 in all groups (P < .05). The fecal and cecal SCFA displayed higher concentrations of acetate and propionate and a higher molar proportion of propionate in RS 2 than in RS 1 or control rats (P < .05). Stimulation of bifidobacteria, lactobacilli, and SCFA may be useful for the suppression of pathogenic organisms in the colon.
Kleessen
B
B
German Institute of Human Nutrition, Potsdam-Rehbrücke, Germany.
Stoof
G
G
Proll
J
J
Schmiedl
D
D
Noack
J
J
Blaut
M
M
D000085:Acetates / Q000032:analysis; D000818:Animals; D001439:Bacteroides / Q000302:isolation & purification; D001644:Bifidobacterium / Q000302:isolation & purification; D002087:Butyrates / Q000032:analysis; D002432:Cecum / Q000737:chemistry* / Q000382:microbiology*; D004032:Diet / Q000662:veterinary*; D004435:Eating / Q000502:physiology; D004754:Enterobacter / Q000302:isolation & purification; D005232:Fatty Acids, Volatile / Q000032:analysis*; D005243:Feces / Q000737:chemistry* / Q000382:microbiology*; D007778:Lactobacillus / Q000302:isolation & purification; D008297:Male; D011422:Propionates / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D011198:Solanum tuberosum / Q000737:chemistry; D013213:Starch / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D013291:Streptococcus / Q000302:isolation & purification; D013997:Time Factors; D015430:Weight Gain / Q000502:physiology; D003313:Zea mays / Q000737:chemistry
D000085:Acetates; D002087:Butyrates; D005232:Fatty Acids, Volatile; D011422:Propionates; D013213:Starch