Isomaltodextrin, a highly branched α-glucan, increases rat colonic H₂ production as well as indigestible dextrin

Figures & data

Table 1. Food intake, bodyweight gain, breath and flatus H₂ excretion, portal and abdominal H₂ concentrations in rats fed nondigestible α-glucan for 14 days (Expt. 1).

	C	IMD	ID	HAS
Food intake, g	309 ± 10^a	278 ± 8^bc	273 ± 9^c	307 ± 4^ab
Body weight gain, g	64 ± 5	57 ± 4	57 ± 4	68 ± 3
Breath and flatus H2 excretion AUCd0–14, mmol	0.413 (0.202–1.50)^b	18.1 (7.17–54.2)^a	36.8 (18.6–75.7)^a	17.5 (7.03–35.5)^a
Portal H2, μmol/L	0.50 (0.009–2.79)^b	3.11 (1.69–14.1)^a	3.71 (1.69–8.6)^a	9.10 (3.53–18.9)^a
Perinetal fat
Weight, g	6.12 ± 0.53	5.03 ± 0.52	4.67 ± 0.31	6.39 ± 0.47
Weight, g/100 g body weight	1.55 ± 0.12	1.30 ± 0.12	1.22 ± 0.08	1.61 ± 0.12
H2, μmol/kg	0.109 (0.082–0.416)^c	0.478 (0.288–2.84)^b	2.39 (0.189–7.60)^ab	10.8 (3.03–19.1)^a

Notes: Values are expressed as means ± SEM or medians (minimum value-maximum value), n = 8. Values in a row with different superscript letters indicate a statistically significant difference, p < 0.05.

AUC_d0–14, area under the curve for 0–14 days; C, group fed the control diet; HAS, group fed the control diet supplemented with 10.4% high amylose cornstarch; ID, group fed the control diet supplemented with 8.8% indigestible dextrin; IMD, group fed the control diet supplemented with 16.7% isomaltodextrin.

Fig. 1. Change in (breath + flatus) H₂ excretion in rats fed the (C), IMD, ID and HAS diets for 14 days (Expt. 1).

Notes: Values are means, with their standard errors represented by vertical bars, n = 8. Labeled means at a specific time point without a common letter differ, p < 0.05. Repeated-measures 2-way ANOVA was used to analyze H₂ excretion among the three high-fat groups across time (NDS, p < 0.0001; time, p < 0.0001; interaction, p = 0.0052). (C), th group fed the control diet; HAS, group fed the high amylose cornstarch diet (104 g/kg); H₂, hydrogen; ID, group fed the 8.8% indigestible dextrin diet; IMD, groups fed the 16.7% isomaltodextrin diet.

Table 2. Weight of cecal tissue and content, cecal organic acid concentration, and bacterial enzyme activity, counts and ratio in rats fed nondigestible α-glucan for 14 days (Expt. 1).

	C	IMD	ID	HAS
Tissue, g	0.749 (0.641–0.935)^c	1.25 (1.15–1.29)^b	1.52 (1.28–1.63)^a	1.22 (0.959–1.51)^ab
Contents
Weight, g	3.21 (2.50–3.62)^c	7.22 (6.11–8.99)^b	12.0 (8.23–14.7)^a	6.47 (5.55–10.7)^b
pH	6.47 ± 0.05^b	5.77 ± 0.06^a	5.66 ± 0.03^a	5.70 ± 0.05^a
Organic acid, μmol/g
Acetate	28.8 (24.0–41.2)^a	22.3 (14.9–32.3)^ab	23.4 (19.8–25.5)^b	34.6 (25.9–55.4)^a
Propionate	10.6 (9.18–13.2)^a	11.3 (8.76–13.0)^a	8.48 (3.97–17.4)^ab	7.24 (5.24–9.56)^b
n-Butyrate	2.32 (0.728–3.48)^b	2.47 (2.08–3.41)^b	5.07 (2.35–8.81)^a	7.44 (4.20–9.78)^a
Succinate	21.0 (13.0–29.0)^b	54.1 (49.3–62.7)^a	43.4 (38.1–55.8)^a	51.9 (21.4–65.7)^a
Bacterial enzyme, units/g cecal content
α-D-glucosidase	14.8 (11.5–21.2)^b	27.7 (9.86–50.0)^ab	37.5 (18.5–98.4)^a	8.73 (3.44–31.2)^b
β-D-glucosidase	1.42 (1.21–1.49)^b	0.707 (0.568–1.33)^c	3.53 (1.87–8.29)^a	0.789 (0.668–1.28)^c
α-D-galactosidase	4.98 (4.42–5.45)^a	1.29 (0.977–1.67)^c	3.06 (1.64–4.66)^b	1.10 (0.876–1.50)^c
β-D-galactosidase	8.12 ± 0.55^a	2.99 ± 0.63^c	5.30 ± 0.66^b	2.51 ± 0.42^c
Bacteria counts, log10copies/g
Total bacteria	12.2 ± 0.1^b	12.6 ± 0.1^a	12.7 ± 0.0^a	12.8 ± 0.0^a
Phylum
Firmicutes (F)	12.0 ± 0.1^b	12.0 ± 0.0^b	12.4 ± 0.0^a	12.5 ± 0.1^a
Bacteroidetes (B)	11.5 ± 0.1^b	12.3 ± 0.1^a	12.2 ± 0.0^b	12.2 ± 0.1^b
F:totalbacteria	0.716 ± 0.027^a	0.229 ± 0.032^c	0.522 ± 0.027^b	0.571 ±0.05^b
B:total bacteria	0.213 ± 0.016^b	0.508 ± 0.030^a	0.315 ± 0.015^b	0.279 ± 0.042^b
F/B	3.54 ± 0.34^a	0.50 ± 0.11^c	1.71 ± 0.17^b	2.57 ± 0.53^ab
Genus
Bacteroides–Prevotella	10.5 ± 0.2^c	11.8 ± 0.1^ab	11.6 ± 0.1^b	12.1 ± 0.1^a
Clostridium cluster XIVa	11.3 ± 0.1^b	11.5 ± 0.0^b	11.9 ± 0.0^a	11.8 ± 0.1^a
Lactobacillus	10.5 ± 0.1	10.8 ± 0.2	11.1 ± 0.2	10.9 ± 0.1
Bifidobacterium	8.23 ± 0.11^b	10.3 ± 0.1^a	8.48 ± 0.38^b	10.5 ± 0.3^a

Notes: Values are expressed as means ± SEM or medians (minimum value–maximum value), n = 8. Values in a row with different superscript letters indicate a statistically significant difference, p < 0.05.

Enzymatic activity was expressed as micromoles of product formed per minute (unit) per gram of cecal content.

C, group fed the control diet; HAS, group fed the control diet supplemented with 10.4% high amylose cornstarch; ID, group fed the control diet supplemented with 8.8% indigestible dextrin; IMD, group fed the control diet supplemented with 16.7% isomaltodextrin.

Table 3. Dose response of isomaltodextrin on food intake, bodyweight gain, breath and flatus H₂ excretion, portal and abdominal H₂ concentrations in rats.

	C	3.3IMD	6.7IMD	10IMD	16.7IMD
Food intake, g	323 ± 14	324 ± 10	311 ± 14	300 ± 5	278 ± 12
Body weight gain, g	77 ± 5^a	82 ± 4^a	78 ± 4^a	74 ± 3^ab	59 ± 5^b
Breath and flatus H2 excretion AUCd0–14, mmol	0.319 (0.183–0.944)^d	1.77 (0.506–2.55)^c	7.51 (2.99–22.9)^ab	9.59 (4.13–17.4)^b	20.9 (11.5–27.6)^a
Portal H2, μmol/L	0.230 (0.120–2.79)^b	1.11 (0.39–5.98)^ab	4.93 (1.76–8.66)^a	7.70 (2.01–9.53)^a	5.99 (3.75–13.5)^a
Perirenal fat
Weight, g	7.37 ± 0.58^a	7.25 ± 0.44^a	6.62 ± 0.64^ab	6.38 ± 0.38^ab	5.08 ± 0.38^b
Weight, g/100 g body weight	1.90 ± 0.12^a	1.85 ± 0.10^a	1.68 ± 0.14^ab	1.65 ± 0.10^a	1.38 ± 0.0^b
H2, μmol/kg	0.105 (0.011–0.219)^c	0.104 (0.053–1.31)^bc	0.880 (0.193–2.21)^ab	1.19 (0.250–10.8)^ab	2.92 (0.474–15.2)^a

Notes: Values are expressed as means ± SEM or medians (minimum value-maximum value), n = 8. Values in a row with different superscript letters indicate a statistically significant difference, p < 0.05.

AUC_d0–14, area under the curve for 0–14 days; C, group fed the control diet; 3.3IMD-16.7IMD, group fed the control diet supplemented with 3.3–16.7% isomaltodextrin.

Fig. 2. Dose response of IMD on (breath + flatus) H₂ excretion in rats (Expt. 2).

Notes: Values are means, with their standard errors represented by vertical bars, n = 8. Labeled means at a specific time point without a common letter differ, p < 0.05. Repeated-measures 2-way ANOVA was used to analyze H₂ excretion among the three high-fat groups across time (dose, p < 0.0001; time, p < 0.0001; interaction, p < 0.0001). C, th group fed the control diet; H₂, hydrogen; 3.3IMD-16.7IMD, groups fed the 3.3–16.7% isomaltodextrin diet.

Table 4. Dose response of isomaltodextrin on weight of cecal tissue and content, cecal organic acid concentration, and bacterial enzyme activity, counts and ratio in rats.

	C	3.3IMD	6.7IMD	10IMD	16.7IMD
Tissue, g	0.711 (0.609–0.774)^d	0.853 (0.777–0.934)^c	0.911 (0.830–1.04)^bc	1.02 (0.970–1.23)^b	1.25 (1.09–1.66)^a
Contents
Weight, g	2.95 (2.58–3.33)^d	3.71 (3.22–4.61)^c	4.77 (2.67–6.18)^bcd	7.01 (5.56–8.10)^b	8.89 (6.96–10.9)^a
pH	6.72 ± 0.09^a	6.46 ± 0.05^a	5.82 ± 0.07^ab	5.51 ± 0.06^ab	5.45 ± 0.10^b
Organic acid, μmol/g
Acetate	43.9 (36.4–48.3)	44.1 (35.2–53.4)	41.6 (26.5–55.2)	38.0 (30.8–52.8)	35.3 (28.3–52.7)
Propionate	13.8 (10.3–15.3)^b	16.2 (12.9–18.6)^ab	14.1 (9.94–16.3)^ab	15.6 (14.8–17.5)^a	19.5 (12.5–21.3)^ab
n-Butyrate	4.56 (3.71–5.25)^b	4.58 (0.00–5.95)^ab	5.28 (4.68–8.72)^a	5.54 (4.02–8.25)^ab	6.06 (5.33–16.2)^a
Succinate	3.90 (1.35–15.4)^b	15.2 (6.83–19.8)^b	43.6 (35.7–54.2)^a	49.5 (33.0–63.4)^a	53.4 (41.4–65.5)^a
Bacterial enzyme, units/g cecal content
α-D-glucosidase	18.7 (16.5–26.3)^b	57.8 (38.9–78.9)^a	63.5 (36.5–73.1)^a	55.0 (31.2–92.9)^a	54.2 (26.8–77.1)^a
β-D-glucosidase	1.35 (1.06–1.50)^ab	1.87 (1.09–2.74)^a	1.61 (1.15–2.09)^ab	1.42 (1.32–1.64)^ab	0.99 (0.68–1.83)^b
α-D-galactosidase	5.14 (3.79–7.66)^a	4.85 (3.04–7.15)^ab	3.63 (2.74–5.35)^abc	3.27 (2.48–3.72)^bc	2.44 (1.45–3.74)^c
β-D-galactosidase	5.86 (5.04–8.18)^a	7.22 (4.19–9.79)^a	4.68 (3.64–7.21)^ab	4.25 (3.58–4.79)^b	3.70 (2.93–5.59)^b
Bacteria counts, log10copies/g
Total bacteria	12.0 ± 0.1^bc	11.7 ± 0.1^c	12.0 ± 0.1^bc	12.4 ± 0.1^ab	12.4 ± 0.1^a
Pylum
Firmicutes (F)	11.8 ± 0.1^a	11.5 ± 0.1^ab	11.4 ± 0.0^b	11.6 ± 0.1^ab	11.4 ± 0.2^b
Bacteroidetes (B)	11.3 ± 0.1^c	11.3 ± 0.1^c	11.8 ± 0.1^b	12.1 ± 0.1^ab	12.2 ± 0.1^a
F:total bacteria	0.640 ± 0.043^a	0.603 ± 0.053^a	0.251 ± 0.047^b	0.202 ± 0.044^b	0.123 ± 0.034^b
B:total bacteria	0.201 ± 0.028^b	0.357 ± 0.027^b	0.606 ± 0.041^a	0.600 ± 0.073^a	0.726 ± 0.043^a
F/B	3.82 ± 0.72^a	1.82 ± 0.27^b	0.47 ± 0.12^bc	0.65 ± 0.39^bc	0.19 ± 0.07^c
Genus
Bacteroides–Prevotella	11.1 ± 0.1^c	11.1 ± 0.1^c	11.7 ± 0.1^b	12.0 ± 0.1^ab	12.2 ± 0.1^a
Clostridium cluster XIVa	11.5 ± 0.1^a	11.1 ± 0.1^ab	11.1 ± 0.0^ab	11.3 ± 0.1^ab	11.1 ± 0.1^b
Lactobacillus	10.7 ± 0.1	9.89 ± 0.1	10.1 ± 0.1	10.5±0.3	10.3 ± 0.3
Bifidobacterium	7.83 ± 0.11^b	7.48 ± 0.22^b	9.71 ± 0.29^a	10.2 ± 0.3^a	10.0 ± 0.3^a

Notes: Values are expressed as means ± SEM or medians (minimum value–maximum value), n = 8. Values in a row with different superscript letters indicate a statistically significant difference, p < 0.05.

Enzymatic activity was expressed as micromoles of product formed per minute (unit) per gram of cecal content.

C, group fed the control diet; 3.3IMD-16.7IMD, group fed the control diet supplemented with 3.3–16.7% isomaltodextrin.

Table 5. Comparison between isomaltodextrin and fructooligosaccharide on food intake, bodyweight gain, breath and flatus H₂ excretion, portal and abdominal H₂ concentrations in rats.

	C	16.7IMD	5.2FOS
Body weight gain, g	77 ± 5^a	59 ± 5^b	68 ± 4^ab
Food intake, g	323 ± 14^a	278 ± 12^b	292 ± 9^ab
Breath and flatus H2 excretion AUCd0–14, mmol	0.319 (0.183–0.944)^b	20.9 (11.5–27.6)^a	19.0 (14.6–46.5)^a
Portal H2, μmol/L	0.230 (0.120–4.71)^b	5.99 (3.75–13.5)^a	16.4 (5.43–22.4)^a
Perirenal fat
Weight, g	7.37 ± 0.58^a	5.08 ± 0.38^b	5.41 ± 0.41^b
Weight, g/100 g body weight	1.90 ± 0.12^a	1.38 ± 0.08^b	1.41 ± 0.10^b
H2, μmol/kg	0.105 (0.011–0.219)^b	2.92 (0.474–15.2)^a	7.65 (1.12–28.5)^a

Notes: Values are expressed as means ± SEM or medians (minimum value–maximum value), n = 8. Values in a row with different superscript letters indicate a statistically significant difference, p < 0.05.

AUC_d0–14, area under the curve for 0–14 days; C, group fed the control diet; 5.2FOS, group fed the control diet supplemented with 5.2% fructooligosaccharide; 16.7IMD, group fed the control diet supplemented with 16.7% isomaltodextrin.

Fig. 3. Comparison between IMD and FOS on (breath + flatus) H₂ excretion in rats (Expt. 3).

Notes: Values are means, with their standard errors represented by vertical bars, n = 8. Labeled means at a specific time point without a common letter differ, p < 0.05. Repeated-measures 2-way ANOVA was used to analyze H₂ excretion among the three high fat groups across time (NDF, p < 0.0001; time, p < 0.0001; interaction, p < 0.0046). C, th group fed the control diet; FOS, groups fed the 5.2% fructooligosaccharide diet; H₂, hydrogen; IMD, groups fed the 16.7% isomaltodextrin diet.

Table 6. Comparison between isomaltodextrin and fructooligosaccharide on weight of cecal tissue and content, cecal organic acid concentration, and bacterial enzyme activity, counts and ratio in rats.

	C	16.7IMD	5.2FOS
Tissue, g	0.711 (0.609–0.774)^b	1.25 (1.09–1.66)^a	1.26 (1.04–1.52)^a
Contents
Weight, g	2.95 (2.58–3.33)^c	8.89 (6.96–10.9)^a	5.98 (4.00–8.92)^b
pH	6.72 ± 0.09^a	5.45 ± 0.10^b	5.49 ± 0.12^b
Organic acid, μmol/g
Acetate	43.9 (36.4–48.3)^b	35.3 (28.3–52.7)^b	65.7 (47.0–91.8)^a
Propionate	13.8 (10.3–15.3)^b	19.5 (12.5–21.3)^a	5.92 (3.88–13.6)^c
n-Butyrate	4.56 (3.71–5.25)^c	6.06 (5.33–16.2)^b	23.6 (22.0–35.5)^a
Succinate	3.90 (1.35–15.4)^c	53.4 (41.4–65.5)^a	16.0 (8.17–25.1)^b
Bacterial enzyme, units/g cecal content
α-D-glucosidase	18.7 (16.5–26.3)^b	54.2 (26.8–77.1)^a	15.5 (12.5–18.9)^c
β-D-glucosidase	1.35 (1.06–1.50)^b	0.99 (0.68–1.83)^b	1.60 (1.34–2.98)^a
α-D-galactosidase	5.14 (3.79–7.66)^a	2.44 (1.45–3.74)^b	3.37 (2.47–6.26)^b
β-D-galactosidase	5.86 (5.04–8.18)^a	3.70 (2.93–5.59)^b	8.49 (4.16–12.8)^a
Bacteria counts, log10copies/g
Total bacteria	12.0 ± 0.1^c	12.4 ± 0.1^b	12.7 ± 0.1^a
Pylum
Firmicutes (F)	11.8 ± 0.1^b	11.4 ± 0.2^c	12.7 ± 0.1^a
Bacteroidetes (B)	11.3 ± 0.1^b	12.2 ± 0.1^a	11.5 ± 0.1^b
F:total bacteria	0.640 ± 0.043^b	0.123 ± 0.034^c	0.913 ± 0.027^a
B:total bacteria	0.201 ± 0.028^b	0.726 ± 0.043^a	0.069 ± 0.09^c
F/B	3.82 ± 0.72^b	0.19 ± 0.07^b	16.2 ± 3.2^a
Genus
Bacteroides–Prevotella	11.1 ± 0.1^c	12.2 ± 0.1^a	11.5 ± 0.1^b
Clostridium cluster XIVa	11.5 ± 0.1^b	11.1 ± 0.1^c	12.1 ± 0.1^a
Lactobacillus	10.7 ± 0.1	10.3 ± 0.3	10.8 ± 0.1
Bifidobacterium	7.83 ± 0.11^c	10.0 ± 0.3^b	11.7 ± 0.2^a

Notes: Values are expressed as means ± SEM or medians (minimum value-maximum value), n = 8. Values in a row with different superscript letters indicate a statistically significant difference, p < 0.05.

Enzymatic activity was expressed as micromoles of product formed per minute (unit) per gram of cecal content.

C, group fed the control diet; 5.2FOS, group fed the control diet supplemented with 5.2% fructooligosaccharide; 16.7IMD, group fed the control diet supplemented with 16.7% isomaltodextrin.