Subscriber access provided by NEW YORK UNIV
Article
In vitro fermentation of porcine milk- and galactooligosaccharides using piglet fecal inoculum E. Difilippo, Feipeng Pan, Madelon Logtenberg, Rianne (H.A.M.) Willems, S. Braber, J. Fink-Gremmels, Henk A. Schols, and H. Gruppen J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.5b05384 • Publication Date (Web): 22 Feb 2016 Downloaded from http://pubs.acs.org on February 22, 2016
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 25
Journal of Agricultural and Food Chemistry
1
Abstract
2
In this study, the in vitro fermentation by piglet fecal inoculum of galacto-oligosaccharides
3
(GOS) and porcine milk oligosaccharides (PMOs) was investigated in order to identify
4
possible preferences for individual oligosaccharide structures by piglet microbiota. Firstly
5
acidic PMOs and GOS with degree of polymerization 4-7 were depleted within 12 h of
6
fermentation, whereas fucosylated and phosphorylated PMOs were partially resistant to
7
fermentation. GOS structures containing β1-3 and β1-2 linkages were preferably fermented
8
over GOS containing β1-4 and β1-6 linkages. Upon in vitro fermentation, acetate and butyrate
9
were produced as the main organic acids. GOS fermentation by piglet inoculum showed
10
unique fermentation pattern with respect to preference of GOS size and organic acids
11
production.
12 13
Keywords: human fermentation, fibers, non-digestible carbohydrates, gas chromatography,
14
liquid chromatography, short chain fatty acids, sugars, organic acids
2
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 2 of 25
15
Introduction
16
Milk is the first food source for infants, providing not only energy but also offering protection
17
against pathogens.1 The third largest class of compounds present in human milk are
18
oligosaccharides (HMOs).1 Numerous health related effects of HMOs, involving direct
19
interactions with pathogen and/or indirect effects upon their fermentation by the intestinal
20
microbiota have been reported.2 When human milk is lacking during the early stage of life of
21
infants, cow milk based infant formula is used.3, 4 However, cow milk has a low content of
22
milk oligosaccharides, therefore in many cases infant formulas are fortified with prebiotics
23
such as galacto-oligosaccharides (GOS).5,
24
ingredients that can influence the intestinal microbiota composition resulting in beneficial
25
effects for the host.5, 7, 8 GOS are produced from lactose using β-galactosidases of microbial or
26
yeast source.9 The enzymatic reaction results in a GOS mixture containing oligosaccharides
27
varying in degree of polymerization, mostly from 2 to 8, and in types of glycosidic linkages
28
present.5 Commonly, GOS have a glucose monomer at their reducing end to which multiple
29
galactose monomers with different linkages (β1-2, β1-3, β1-4 and β1-6) are attached.10 GOS
30
exhibit less structural complexity than HMOs. The major part GOS resist degradation in the
31
upper intestinal tract, consequently reaching the colon, as is the case for HMOs.8, 11-13 In the
32
colon, GOS enhance Bifidobacteria growth, potentially protecting the infant against infections
33
and pathogen development.2,
34
(SCFAs) are produced, among which butyrate.15 Butyrate have been shown to be anti-
35
inflammatory and anti-carcinogenic, also enhancing (in vitro) the intestinal barrier function.5,
36
16, 17
14
6
Prebiotics are defined as non-digestible food
Moreover, upon GOS fermentation, short chain fatty acids
Recent study showed that in vivo GOS fermentation in young pigs (piglets) was
37
extensive, not being conclusive on microbiota utilization towards individual GOS structures.18
38
The understanding of the preference of microbiota towards specific oligosaccharide structures 3
ACS Paragon Plus Environment
Page 3 of 25
Journal of Agricultural and Food Chemistry
39
is important for the understanding of bacterial metabolization by the intestinal microbiota
40
including enzyme activity involved and to target specific oligosaccharides to be more
41
beneficial for the gut microbiota for animal health. In the present study, in vitro fermentation
42
by piglet fecal inoculum was used in order to control different stages of fermentation, thereby
43
focusing on the fate of individual oligosaccharides and organic acids produced.
44
Oligosaccharides investigated were from porcine milk as present as primary feed source at
45
early stage of piglet life and GOS.
46
Materials and methods
47
Acetic acid, acetonitrile (ACN), ammonium formate, formic acid, chloroform and methanol
48
were purchased from Biosolve BV (Valkenswaard, The Netherlands). Butyric acid, lactic
49
acid, succinic acid, maltotriose, 2-(N-morpholino)ethanesulfonic acid, 2-ethylbutyric acid,
50
sodium chloride, 2-picoline borane complex and sodium hydroxide were purchased from
51
Sigma Aldrich (Steinheim, Germany). Propionic acid, oxalic acid and 2-aminobenzamide
52
were purchased from VWR International (Amsterdam, The Netherlands). β3’-, β4’- and β6’-
53
Galactosyllactose were purchased from Carbosynth (Compton, UK), while 3’- and 6’- sialyl-
54
N-acetylactosamine, 3’-fucosyllactose, lacto-N-(neo)tetraose and lacto-N-(neo)hexaose were
55
purchased from Dextra (Reading, UK). 3’- and 6’-Sialyllactose and lacto-N-fucosylpentaose
56
were purchased from Sigma Aldrich. Water was filtered using a Milli-Q water purification
57
system (Millipore, Darmstadt, Germany) and it was referred as water in the text. Vivinal GOS
58
powder (FrieslandCampina Domo, Borculo, The Netherlands), dry matter (DM) 97%, with
59
GOS 69%, lactose 23%, glucose and galactose together 5% on DM, is referred to in the text
60
as GOS. Composition of GOS-DPs are 31% for GOS-DP2 (different from lactose), 38% for
61
DP3, 18%
62
manufacture.
for DP4, 8% for DP5 and 5% w/w for GOS-DP≥5, as reported by the
4
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 4 of 25
63
Oligosaccharide extraction and separation
64
Porcine milk oligosaccharides (PMOs) from porcine colostrum (37 mL) (Proefaccommodatie
65
de Tolakker, Utrecht University, Utrecht, The Netherlands) were extracted, freeze-dried and
66
dissolved in water (70 mg/mL), and subsequently separated using Size Exclusion
67
Chromatography (SEC) as reported elsewhere.19 Collection of 103 fractions (7 mL each) was
68
performed as described before.19 In total, 4 runs were performed with an injection volume of
69
2.86 mL each injection. Afterwards, the fractions were pooled and freeze dried: pool 1:
70
fraction 290 - 500 mL, pool 2: fraction 501 - 697 mL, pool 3: fraction 698 - 719 mL, pool 4:
71
fraction 720- 741 mL, pool 5: fraction 742 - 770 mL. The freeze-dried pools were dissolved
72
in 36 mL water. For each pool, 1 mL was used for oligosaccharide characterization, while the
73
remaining volumes were mixed and freeze dried again to obtain porcine milk oligosaccharides
74
(PMOs) with a reduced amount of lactose and PMOs with DP2.
75
Fermentation of GOS and PMOs by pig fecal inoculum
76
Culture medium
77
The culture medium was based on a modified simulated ileal environment medium (SIEM),
78
not containing carbohydrates prepared as reported elsewhere.20 The pH was set at 6.0 using
79
MES buffer. All the culture medium components were provided by Tritium Microbiology
80
(Veldhoven, The Netherlands).
81
Fecal inoculum
82
Inoculum for the in vitro fermentation was obtained from fecal material from 3 Dutch
83
Landrace piglets (age of 3 weeks). The piglets were fed on porcine milk over the feeding
84
period, combined with pig formula (de Heus, Ede, The Netherlands) for the 2nd day to the 8th
85
day of life. From the 9th day of life until the end of the 3 weeks the piglets received pellets (de 5
ACS Paragon Plus Environment
Page 5 of 25
Journal of Agricultural and Food Chemistry
86
Heus). Immediately after defecation, fecal material from each piglet was collected in
87
eppendorf tubes, which was immediately put into an insulated box with crushed ice and
88
afterwards stored at -80 °C. The pig fecal inoculum was prepared as described elsewhere,
89
with some minor modifications.21 Feces (± 100mg) of three piglets were pooled after
90
defrosting in an anaerobic cabinet (gas phase: 96% N2 and 4% H2). The pooled feces were
91
diluted 6 times (w/v) with sterilized 0.9% (w/v) NaCl solution and subsequently homogenized
92
using a vortex. The homogenization was facilitated by the addition of sterile glass beads. The
93
fecal solution was added to the culture medium in a 20 mL flasks at a 5:82 (v/v) ratio, in order
94
to obtain the final inoculum. Afterwards, the bottle was closed with rubber stoppers and
95
aluminum caps to maintain anaerobic conditions. Next, the inoculum was kept overnight into
96
an incubator shaker (Innova 40, New Brunswick Scientific, Nijmegen, The Netherlands) (39
97
°C, 100 rpm) to stabilize the bacterial population.
98
In vitro fermentation
99
GOS and PMOs, obtained as described above, were used as substrates for the fermentation by
100
pig fecal inoculum. The in vitro fermentation experiment was performed as described
101
elsewhere with minor modifications.21 GOS or PMOs were added to the culture medium with
102
a final substrate concentration of 11.1 mg/mL. The fecal inoculum was added to the solution
103
containing substrate and medium in a 1:10 ratio (v/v) and a final volume of 10 mL for the
104
fermentation flasks. Control samples consisting of culture medium without substrate were
105
used to monitor the background fermentation. All procedures were performed in an anaerobic
106
cabinet. Flasks were closed with rubber stoppers and aluminum caps, and they were put into
107
an incubator shaker (Innova 40) (100 rpm, 39 °C). After 9, 10, 12, 24 and 48 hours of the
108
fermentation, two times 70 µL were taken from the fermentation bottles with a syringe and
6
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 6 of 25
109
transferred to eppendorf tubes. In order to inactivate fecal enzymes, eppendorf tubes were put
110
into a boiling water bath for 5 min and stored afterwards at -20oC.
111
Characterization and quantification of GOS and PMOs
112
Samples after fermentation were cleaned prior to analysis by hydrophilic interaction liquid
113
chromatography with mass spectrometry (HILIC-ESI-MSn). The samples after fermentation
114
were diluted 10 times in water and 150 µL were placed into a polyvinylidene fluoride
115
centrifugal filter unit (0.22 µm, Merck Millipore, Amsterdam, The Netherlands) and
116
centrifuged (5 min, 20000g, 20oC). Afterwards, ACN was added to the filtrate in a ratio of 1:1
117
(v/v) and the samples were centrifuged (5 min, 20000g, 20oC). Supernatants were analyzed on
118
a Thermo Accela Ultra High Liquid Chromatography (UHPLC) system (Thermo Scientific,
119
Waltham, MA, USA.) as described elsewhere.22 Briefly, The mobile phases used were: A =
120
water + 1% (v/v) acetonitrile (ACN), B = ACN, and C = 200 mM ammonium formate buffer
121
(pH 4.5) with a flow rate of 300 µL/min. The elution profile was: isocratic 85% B (0-1 min);
122
85-60% B (1-31 min); from 60-40% B (31-35 min); isocratic 40% B (35-36 min); from 40-
123
85% B (36-36.1 min); isocratic 85% B (36.1-45 min). The mobile phase C was kept at 5%
124
during the entire gradient, with auto-sampler and column oven temperature of 15 and 35 °C,
125
respectively.
126
In order to recognize GOS linkage type, HPAEC-PAD was used and the HPAEC profiles
127
were compared with profiles as reported elsewhere.10, 15 Oligosaccharides standards were used
128
for PMO characterization and quantification by HILIC-MSn.. Calibration curves of the
129
corresponding milk oligosaccharide standards and GOS (0.002 to 0.5 mg/mL respectively)
130
were used in order to quantify PMOs and GOS by mass spectrometry. Area and concentration
131
of individual GOS-DP were obtained by selecting the mass range for each GOS-DP and
132
taking into account the relative amount of a given GOS-DP in the total GOS sample. If no 7
ACS Paragon Plus Environment
Page 7 of 25
Journal of Agricultural and Food Chemistry
133
corresponding standards for neutral PMOs were available, GOS with a comparable DP was
134
used for the calibration curve. The curves fitting the PMO standards showed a linear
135
correlation with R2 of 0.90-0.99, while the curves fitting the GOS-DPs showed a linear
136
correlations with R2 of 0.98-0.99.
137
Organic acid analysis
138
In order to quantify acetate, propionate and butyrate produced during the fermentation, GC
139
analysis was performed as described elsewhere with minor modifications.15 Samples after
140
fermentation were diluted 10 times with water. Aliquots (50 µL) and SCFAs standards (0.01-
141
3 mg/mL) were mixed with 0.15 M oxalic acid (50 µL). The solutions were kept for 30 min
142
before addition of 0.025 mg/mL 2-ethyl butyric acid as internal standard in water (143 µL). In
143
order to analyze succinic and lactic acid, high performance liquid chromatography with
144
refractive index detection was performed as described elsewhere.15 Briefly, Dionex system
145
(Ultimate 3000 HPLC) equipped with Aminex HPX-87H column with a guard column (Bio-
146
Rad, Hercules, CA, USA) was used, with a H2SO4 (5 mM) mobile phase with a flow rate of
147
0.6 mL/min at 65oC.
148 149
Results and discussion
150
Fermentation of porcine milk oligosaccharides (PMOs)
151
As a result of rapid colonic bacterial colonization, piglets can extensively ferment dietary
152
fibers.22-26 GOS and PMOs present in the diet of piglets are almost completely fermented in
153
the colon, resulting in trace amounts of oligosaccharides present in the feces other than intact
154
GOS or PMO structures.18,
155
fermentation of GOS is suggested to start already in the small intestine and to continue
156
extensively in cecum and colon.24, 25 In order to study any preference and differentiation in
22
Similarly as found for dietary fibers, piglets intestinal
8
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 8 of 25
157
rate of fermentation among GOS and PMO structures, in vitro fermentation was performed
158
using pig fecal inocula. Prior to monitor their degradation profiles, the main PMOs were
159
identified and quantified by HILIC-MSn.19 Through single ion monitoring, in total thirteen
160
main PMOs representing about 77% of the total peak area, were identified and monitored
161
during the in vitro fermentation. Using previously gained knowledge,22 PMOs identified were
162
the neutral β3’- and β6’- galactosyllactose (β3’- and β6’-GL), lacto-N-neotetraose (LNnT),
163
lacto-N-pentaose-I (LNP-I), lacto-N-neohexaose (LNnH), 2’- and 3’- fucosyllactose (2’- and
164
3’-FL); and the acidic 3’- and 6’- sialyllactose (3’- and 6’-SL), 3’- and 6’- sialyl-N-
165
acetyllactosamine (3’- and 6’-SLN), phosphorylated lactose (P+ lactose) and Neu5Ac(α2-
166
6)GlcNAc(β1-3)Gal(β1-4)Glc. The degradation of individual PMOs during fermentation was
167
indirectly expressed via the abundance of remaining oligosaccharides present (Figure 1).
168
Overall, a decrease in concentration upon fermentation was observed for each PMO, with
169
individual differences in degradation rate (Figure 1). One exception was phosphorylated
170
lactose, which increased in concentration during the first 12 h of fermentation, while being
171
partially depleted afterwards (Figure 1 C). The lactose present was attributed partially to the
172
small amount of lactose still present after purification with SEC and partially to lactose
173
released by bacterial degradation of PMOs. Lactose was the first carbohydrate to be fully
174
fermented by the porcine microbiota, decreasing approximately 98% during the first 9 h of
175
fermentation. Trimers, such as β3’-GL, β6’-GL, 2’-FL and 3’-FL were all fermented with a
176
different rate.
177
The trimers β3’-GL and β6’-GL diminished about 50% of their initial concentrations in the
178
first 9 h of fermentation, whereby β3’-GL is more quickly fermented than β6’-GL (Figure 1
179
B). LNnH is fermented faster than LNnT and LNnP-I, decreasing 80% of its original 9
ACS Paragon Plus Environment
Page 9 of 25
Journal of Agricultural and Food Chemistry
180
concentration during 12 h of fermentation. All the neutral PMOs are almost completely
181
fermented within 24 h, whereas LNnT still was not consumed completely. Most probably,
182
part of the LNnT present at 24 h is released by the degradation of larger PMOs.27 LNnT is
183
totally consumed in the subsequent 24 h by the piglet colonic microbiota. Acidic PMOs are
184
fermented for 50% during the first 12 h and are fermented faster than neutral PMOs (Figure 1,
185
C). Surprisingly, the phosphorylated lactose (P+lactose) more than doubled in concentration
186
during the first 12 h of fermentation, with a subsequent decrease to about 50% of its starting
187
concentration. Hypothetically, the increase of phosphorylated lactose could be derived from
188
fermentation of larger phosphorylated PMOs present, although they were not reported so far
189
to be present in domestic animal milk samples.22, 27 Overall, fermentation of acidic and neutral
190
PMOs was almost complete in 48 h, with the exception of fucosylated PMOs and
191
phosphorylated lactose. The resistance of fucosylated structures during the in vitro
192
fermentation might be an indication of a relevant physiological role by preventing microbial
193
pathogens for binding to intestinal cells in the piglets, as suggested for human studies.28, 29 In
194
conclusion, in vitro fermentation with piglet microbiota showed a rapid consumption of
195
PMOs, with different fermentation rates detected for individual PMOs. Piglet microbiota
196
firstly ferment small PMOs, such as neutral and acidic trimers, and afterwards neutral larger
197
PMOs, each with its own specific rate.
198
Fermentation of galacto-oligosaccharides (GOS)
199
Although GOS are not naturally occurring in the piglet diet, the in vitro fermentation of GOS
200
by piglet fecal microbiota showed that GOS is quite an easy fermentable substrate, as, on
201
average, 36% of residual GOS were present after 12 h of fermentation. However, a difference
202
in fermentation rate was noticed concerning the different GOS-DPs, being present for the 59,
203
42, 29, 27 and 25% for DP3, 4, 5, 6 and 7, respectively, after 12 h of fermentation. GOS-DP2 10
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 10 of 25
204
were fermented first, as expected from a previous investigation on GOS fermented by human
205
fecal inoculum.15 After 24h of fermentation, almost all GOS were metabolized. Lactose as
206
present in the PMOs mixture was totally consumed within the first 12 h of fermentation
207
(Figure 1, A), whereas GOS-DP2 including lactose, was still present for 12% after 12 h of
208
fermentation. Comparing DP2 oligosaccharides in PMOs and GOS (at time point 12 h) it can
209
be concluded that lactose was fermented much faster than non-lactose GOS-DP2 structures.
210
Lactose was introduced in the pig diet not only by nursing, but also by the cow milk based pig
211
formula, presumably leading to adaptation of the pig microbiota to lactose. On the contrary,
212
GOS-DP2 were not present at any phase of the pig diet. Hence, a slower adaptation of the
213
microbiota than for lactose was expected. For GOS-DP3-7 (Figure 2), longer fermentation
214
times compared with fermentation times found for dimers were observed (9-12 h), with
215
different utilization rates depending on the DP. In the first 12 h of in vitro fermentation by
216
piglet fecal inoculum, GOS-DP5-7 were mostly degraded (about 30% remaining
217
oligosaccharides), while GOS-DP3 was still present in relatively high abundance (60%
218
remaining oligosaccharides) (Figure 2). This was not observed during 12 h of in vitro
219
fermentation of GOS by human fecal inoculum, where about 70% of remaining GOS-DP4-6
220
and about 50% of remaining GOS-DP3 were observed.15 After 24h of fermentation, all GOS-
221
DPs showed to be fully fermented without DP discrimination. As expected from GOS
222
fermentation by human fecal inoculum, also piglet fecal microbiota showed preference
223
regarding specific GOS structures.15 Using HPAEC-PAD analysis, not only the decrease
224
during fermentation time of GOS-DP, but also the decrease of individual GOS isomers was
225
monitored. In Figure 3, GOS peaks are assigned with numbers as reported previously.30
226
Isomeric GOS structures were degraded differently depending on their structures as can be
227
seen for lactose and for Gfadapta 11
ACS Paragon Plus Environment
Page 11 of 25
Journal of Agricultural and Food Chemistry
228
OS-DP2 such as Gal(1-3)Gal, Gal(1-3)Glc and Gal(1-2)Glc (Figure 3, numbers 2.3, 2.5 and
229
2.6, respectively). This observation was similar to that observed in a previous study, reporting
230
that β1-2 and β1-3 linkages were more easily degradable than β1-4 linkages during GOS-
231
DP2 fermentation by human fecal inoculum.15 As expected from the HILIC-MSn profile,
232
GOS-DP3 were harder to degrade than GOS-DP2. The trimers indicated by numbers 3.8 and
233
3.9 were easier to ferment by pig inoculum than trimers numbers 3.4, 3.5, 3.6 and 3.7 (Figure
234
3), as expected from GOS fermentation by human fecal inoculum.30
235
A relevant difference between piglet and human inocula, was noticed for Gal(β1-4)Gal(β1-
236
4)Glc and Gal(β1-4)Gal(β1-4)Fru (numbers 3.6 + 3.7, Figure 3), which accumulated with an
237
increase of 17% during the first 12 h of fermentation by piglet fecal inocula, while they were
238
easily fermentable substrates for the human microbiota.15 A similar preference towards the
239
degradation of specific linkages was noticed when comparing piglet and human in vitro
240
fermentation: β1-3/β1-2 linkages were preferred over β1-4/β1-6 linkages for GOS-DP2-3.
241
Literature describes human and pig microbiota composition to be similar, mainly consisting
242
of Firmicutes and Bacteriodes.31 On the other hand, differences were reported to occur in
243
Bifidobacteria species, relevant for GOS degradation.31 Studies reported on extremely low
244
amounts of Bifidobacteria species present in the gastro-intestinal tracts of piglets (< 1% of the
245
total bacteria present).
246
differ from the species reported in human intestinal tract.31, 34 Our results indicate a difference
247
in microbiota composition based on the fermentation characteristics of oligosaccharides.
248
Organic acid production upon PMOs and GOS fermentation by piglet fecal inoculum
249
The degradation of PMOs and GOS by piglet fecal inoculum resulted in the production of
250
organic acids: acetate (A), succinate (S), butyrate (B), lactate (L) and propionate (P) as shown
31-33
Certain Bifidobacteria species present in piglet intestine could
12
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 12 of 25
251
in Figure 4. The molar ratios A:S:B:L:P observed after 24 h of fermentation were of
252
49:1:20:2:27 and 45:1:21:4:29 for PMOs and GOS, respectively. Acetate was the most
253
abundant organic acid detected after 24 h of PMOs and GOS fermentation by piglet fecal
254
inoculum. Similarity acetate was the most abundant organic acid produced for GOS in vitro
255
fermentation by human fecal inoculum.35 Next to acetate, also propionate and butyrate (Figure
256
4, A and B) were produced for both GOS and PMOs fermentation by piglet fecal inoculum,
257
whereas mainly succinate and propionate were co-produced for GOS fermentation by human
258
fecal inoculum.15,
259
human inoculum showed differences in A:S:B:L:P molar ratios: 45:1:21:4:29 and 75:10:6:2:8,
260
for piglet and human inoculum, respectively.15, 16 Overall, after fermentation for 24 h, butyrate
261
was produced in higher abundance upon GOS fermentation by piglet microbiota than by
262
human microbiota.
263
16
For 24 h of in vitro fermentation, GOS fermentation with piglet and
The absolute amount of butyrate was of 1.4 and 0.7 µmol/mg substrate for GOS fermented by
264
piglet and human inoculum, respectively.15,
16
265
inoculum, about 7 and 4 µmol organic acids per mg of substrate were produced for GOS and
266
PMOs, respectively. Fermentation of GOS by human fecal inocula resulted in about 12
267
µmol/mg organic acids production in 24 h of fermentation.15 Overall, in the intestinal tract,
268
1010-11 and 1014 bacteria per gram of intestinal content for piglets and human are present,
269
respectively.31, 36
270
In summary, differently from in vivo piglet fermentation, in vitro fermentation provide the
271
opportunity to observe the preference of piglet microbiota on fermentation of individual
272
oligosaccharides. During in vitro fermentation, acidic PMOs and neutral PMO trimers were
273
the first to be degraded followed by larger neutral PMOs. Fucosylated and phosphorylated
During fermentation for 24 h by piglet
13
ACS Paragon Plus Environment
Page 13 of 25
Journal of Agricultural and Food Chemistry
274
PMO were the most resistant to fermentation. Interestingly, while PMO trimers were quickly
275
degraded, GOS trimers showed a slow apparent degradation rate for the first 12 h of
276
fermentation. GOS trimers degradation rate was hypothesized to be influenced not only by
277
utilization by the microbiota, but also by the release of trimeric degradation products upon
278
fermentation of larger GOS. In addition, GOS containing β1-3 and β1-2 linkages were faster
279
fermented than GOS containing β1-4 and β1-6 linkages. Major products upon PMOs and
280
GOS fermentation by piglet microbiota were acetate, propionate and butyrate.
281
14
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 14 of 25
282
References
283
1.
284
glycoscience. From chemistry to system biology, Kamerling, J. P.; Boons, G. J.; Lee, Y. C.;
285
Suzuki, A.; Taniguchi, N.; Voragen, A. G. J., Eds. Elsevier: Oxford, UK, 2007; Vol. 4, pp
286
695-722.
287
2.
288
Glycobiology 2012, 22, 1147-62.
289
3.
290
formulas and human milk on the development of the faecal flora in newborn infants. Acta
291
Pædiatr 1995, 84, 1347-56.
292
4.
293
Schopfer, H.; Bockler, H. M.; Wells, J., Colon microflora in infants fed formula with galacto-
294
and fructo-oligosaccharides: more like breast-fed infants. J Pediatr Gastr Nutr 2005, 40, 36-
295
42.
296
5.
297
oligosaccharides: production, properties, applications, and significance as prebiotics. Compr
298
Rev Food Sci F 2010, 9, 438-54.
299
6.
300
J. G., Effects of infant formula containing a mixture of galacto- and fructo-oligosaccharides or
301
viable Bifidobacterium animalis on the intestinal microflora during the first 4 months of life.
302
Brit J Nutr 2005, 94, 783-90.
303
7.
304
N.; Macfarlane, G.; Newton, D.; Quigley, M.; Roberfroid, M.; van Vliet, T.; van den Heuvel,
Urashima, T.; Asakuma, S.; Messer, M., Milk oligosaccharides. In Comprehensive
Bode, L., Human milk oligosaccharides: every baby needs a sugar mama.
Kleessen, B.; Bunke, H.; Tovar, K.; Noack, J.; Sawatzki, G., Influence of two infant
Knol, J.; Scholtens, P.; Kafka, C.; Steenbakkers, J.; Gro, S.; Helm, K.; Klarczyk, M.;
Torres, D. P. M.; Gonçalves, M. d. P. F.; Teixeira, J. A.; Rodrigues, L. R., Galacto-
Bakker-Zierikzee, A. M.; Alles, M. S.; Knol, J.; Kok, F. J.; Tolboom, J. J. M.; Bindels,
Van Loo, J.; Cummings, J.; Delzenne, N.; Englyst, H.; Franck, A.; Hopkins, M.; Kok,
15
ACS Paragon Plus Environment
Page 15 of 25
Journal of Agricultural and Food Chemistry
305
E., Functional food properties of non-digestible oligosaccharides: a consensus report from the
306
ENDO project (DGXII AIRII-CT94-1095). Br J Nutr 1999, 81, 121-32.
307
8.
308
modulation of the human colonic microbiota: updating the concept of prebiotics. Nutr Res Rev
309
2004, 17, 259-75.
310
9.
311
effects of galacto-oligosaccharides and other prebiotics. J Appl Microb 2008, 104, 305-44.
312
10.
313
B.; Slaghek, T.; Van Dongen, W., In-depth characterization of prebiotic galacto-
314
oligosaccharides by a combination of analytical techniques. J Agric Food Chem 2009, 57,
315
8488-95.
316
11.
317
foods. PhD Thesis, Wageningen University, Wageningen, The Netherlands 2011.
318
12.
319
M.; German, J. B.; Mills, D. A.; Lebrilla, C. B.; Underwood, M. A., A quantitative and
320
comprehensive method to analyze human milk oligosaccharide structures in the urine and
321
feces of infants. Anal Bioanal Chem 2013, 405, 4089-105.
322
13.
323
prebiotic oligosaccharides are detectable in the faeces of formula-fed infants. Acta Paediatr
324
Suppl 2005, 94, 27-30.
325
14.
326
Microflora 1988, 7, 35-43.
327
15.
328
A., Impact of galacto-oligosaccharides on the gut microbiota composition and metabolic
Gibson, G. R.; Probert, H. M.; Loo, J. V.; Rastall, R. A.; Roberfroid, M. B., Dietary
Macfarlane, G. T.; Steed, H.; Macfarlane, S., Bacterial metabolism and health-related
Coulier, L.; Timmermans, J.; Bas, R.; Van Den Dool, R.; Haaksman, I.; Klarenbeek,
Albrecht, S., Gastrointestinal-active oligosaccharides from human milk and functional
De Leoz, M. L.; Wu, S.; Strum, J. S.; Ninonuevo, M. R.; Gaerlan, S. C.; Mirmiran,
Moro, G. E.; Stahl, B.; Fanaro, S.; Jelinek, J.; Boehm, G.; Coppa, G. V., Dietary
Homma, N., Bifidobacteria as a resistance factor in human beings. Bifidobacteria and
Ladirat, S. E.; Schuren, F. H.; Schoterman, M. H.; Nauta, A.; Gruppen, H.; Schols, H.
16
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 16 of 25
329
activity upon antibiotic treatment during in vitro fermentation. FEMS Microbiol Ecol 2014,
330
87, 41-51.
331
16.
332
Review article: the role of butyrate on colonic function. Aliment Pharm Ther 2008, 27, 104-
333
19.
334
17.
335
of butyrate formation in the human colon. FEMS Microbiol Lett 2002, 217, 133-9.
336
18.
337
H.; Garssen, J.; Fink-Gremmels, J.; Braber, S., The piglet as a model for studying dietary
338
components in infant diets: effects of galacto-oligosaccharides on intestinal functions. Br J
339
Nutr 2016, 115, 605-18.
340
19.
341
H. A., Comparison of milk oligosaccharides pattern in colostrum of different horse breeds. J
342
Agric Food Chem 2015, 63, 4805−14.
343
20.
344
C.; Gruppen, H.; Schuren, F. H., High-throughput analysis of the impact of antibiotics on the
345
human intestinal microbiota composition. J Microbiol Meth 2013, 92, 387-97.
346
21.
347
A., In vitro fermentability of sugar beet pulp derived oligosaccharides using human and pig
348
fecal inocula. J Agric Food Chem 2014, 5, 1079-87.
349
22.
350
Gremmelsb, J.; Schols, H. A.; Gruppen, H., Milk oligosaccharide variation in saw milk and
351
their fermentation in piglet intestine J Agric Food Chem (accepted for publication).
Hamer, H. M.; Jonkers, D.; Venema, K.; Vanhoutvin, S.; Troost, F. J.; Brummer, R. J.,
Pryde, S. E.; Duncan, S. H.; Hold, G. L.; Stewart, C. S.; Flint, H. J., The microbiology
Alizadeh, A.; Akbari, P.; Difilippo, E.; Schols, H. A.; Ulfman, L. H.; Schoterman, M.
Difilippo, E.; Willems, H. A.; Vendrig, J. C.; Fink-Gremmels, J.; Gruppen, H.; Schols,
Ladirat, S. E.; Schols, H. A.; Nauta, A.; Schoterman, M. H.; Keijser, B. J.; Montijn, R.
Leijdekkers, A. G. M.; Aguirre, M.; Venema, K.; Bosch, G.; Gruppen, H.; Schols, H.
Difilippo, E.; Pan, F.; Logtenberg, M.; Willems, H. A. M.; Braberb, S.; Fink-
17
ACS Paragon Plus Environment
Page 17 of 25
Journal of Agricultural and Food Chemistry
352
23.
Houdijk, J. G. M.; Bosch, M. W.; Verstegen, M. W. A.; Berenpas, H. J., Effects of
353
dietary oligosaccharides on the growth performance and faecal characteristics of young
354
growing pigs. Anim Feed Sci Tech 1998, 71, 35-48.
355
24.
356
polysaccharides increases the abundance of Bacteroides-Prevotella-Porphyromonas in ileal
357
microbial community of growing pigs. Animal : an international journal of animal bioscience
358
2014, 8, 1777-87.
359
25.
360
gastrointestinal microbiota and their consequences on intestinal phosphorus metabolism in
361
growing pigs. Asian-Australasian Journal of Animal Sciences 2008, 21, 603-15.
362
26.
363
P. V.; Schoterman, M. H.; Gruppen, H.; Schols, H. A., Oligosaccharides in urine, blood, and
364
feces of piglets fed milk replacer containing galacto-oligosaccharides. J Agric Food Chem
365
2015, 63, 10862-72.
366
27.
367
M.; Rudd, P. M., A comparative study of free oligosaccharides in the milk of domestic
368
animals. Br J Nutr 2014, 111, 1313-28.
369
28.
370
Meinzen-Derr, J. K.; Farkas, T.; Chaturvedi, P.; Pickering, L. K.; Newburg, D. S., Human
371
milk oligosaccharides are associated with protection against diarrhea in breast-fed infants. J
372
Pediatr 2004, 145, 297-303.
373
29.
374
S., Campylobacter jejuni binds intestinal H(O) antigen (Fuc alpha 1, 2Gal beta 1, 4GlcNAc),
Ivarsson, E.; Roos, S.; Liu, H. Y.; Lindberg, J. E., Fermentable non-starch
Metzler, B. U.; Mosenthin, R., A review of interactions between dietary fiber and the
Difilippo, E.; Bettonvil, M.; Willems, R. H.; Braber, S.; Fink-Gremmels, J.; Jeurink,
Albrecht, S.; Lane, J. A.; Marino, K.; Al Busadah, K. A.; Carrington, S. D.; Hickey, R.
Morrow, A. L.; Ruiz-Palacios, G. M.; Altaye, M.; Jiang, X.; Guerrero, M. L.;
Ruiz-Palacios, G. M.; Cervantes, L. E.; Ramos, P.; Chavez-Munguia, B.; Newburg, D.
18
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 18 of 25
375
and fucosyloligosaccharides of human milk inhibit its binding and infection. Journal Biol
376
Chem 2003, 278, 14112-20.
377
30.
378
treatments. PhD Thesis, Wageningen University, Wageningen, The Netherlands 2014.
379
31.
380
into dietary modulation of the human gut microbiota. Nutr Res Rev 2013, 26, 191-209.
381
32.
382
Culture-independent analysis of gut bacteria: the pig gastrointestinal tract microbiota
383
revisited. Appl Environ Microb 2002, 68, 673-90.
384
33.
385
tract (GIT) of the preweaned pig. Livest Sci 2010, 133, 107-9.
386
34.
387
long-chain n-3 PUFA, gut microbiota and fat mass in early postnatal piglet development—
388
exploring a potential interplay. Prostag Leukotr Ess 2011, 85, 345-51.
389
35.
390
Gruppen, H.; Nauta, A.; Schols, H. A., Exploring the effects of galacto-oligosaccharides on
391
the gut microbiota of healthy adults receiving amoxicillin treatment. Brit J Nutr 2014, 112,
392
536-46.
393
36.
394
bacterial community structure in the colon of pigs fed different experimental diets and after
395
infection with Brachyspira hyodysenteriae. Appl Environ Microb 2000, 66, 3290-6.
Ladirat, S. E., Galacto-oligosaccharides to counter the side effects of antibiotic
Heinritz, S. N.; Mosenthin, R.; Weiss, E., Use of pigs as a potential model for research
Leser, T. D.; Amenuvor, J. Z.; Jensen, T. K.; Lindecrona, R. H.; Boye, M.; Moller, K.,
Petri, D.; Hill, J. E.; Van Kessel, A. G., Microbial succession in the gastrointestinal
Andersen, A. D.; Mølbak, L.; Thymann, T.; Michaelsen, K. F.; Lauritzen, L., Dietary
Ladirat, S. E.; Schoterman, M. H. C.; Rahaoui, H.; Mars, M.; Schuren, F. H. J.;
Leser, T. D.; Lindecrona, R. H.; Jensen, T. K.; Jensen, B. B.; Moller, K., Changes in
396
19
ACS Paragon Plus Environment
Page 19 of 25
Journal of Agricultural and Food Chemistry
397
Figure Captions
398
Figure 1. Proportion (%) of remaining PMOs during in vitro batch fermentation by piglet
399
fecal inocula. Concentration per individual PMOs at t = 0 was set to 100%. In A) lactose and
400
2’-, and 3’- fucosyllactose (2’-, and 3’-FL) are shown; in B) β 3’-, and 6’- galactosyllactose (β
401
3’-, and 6’-GL), lacto-N-neotetraose (LNnT), lacto-N-pentaose-I (LNP-I), and lacto-N-
402
neohexaose (LNnH) are shown; while in C) 3’-, and 6’- sialyllactose (3’-, and 6’-SL), 3’-, and
403
6’- sialyl-N-acetyllactosamine (3’-, and 6’-SLN), phosphorylated lactose (P+ lactose), and
404
Neu5Ac(α2-6)GlcNAc(β1-3)Gal(β1-4)Glc are shown.
405
Figure 2. Proportion (area %) of remaining GOS during in vitro fermentation by piglet fecal
406
inoculum as measured by HILIC-MSn. Concentrations per PMOs at t=0 were set to 100%. DP
407
= degree of polymerization.
408
Figure 3. HPAEC-PAD chromatograms of GOS fermentation with piglet fecal inoculum,
409
with structures of oligosaccharides as present in the GOS mixture (2.1-3.9) (according to
410
Ladirat et al.).30 DP= degree of polymerization
411
Figure 4. Organic acid amount and relative concentration during in vitro fermentation of
412
GOS (A) and PMOs (B) by piglet fecal inoculum and of GOS by human fecal inocula. DP =
413
degree of polymerization. Peak numbers correspond to structures in the insert.
414
20
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 20 of 25
Figures Figure 1.
21
ACS Paragon Plus Environment
Page 21 of 25
Journal of Agricultural and Food Chemistry
Figure 2.
Remaining oligosaccharides (% area)
120 100
DP 2 , including lactose
80
DP 3 60
DP 4 DP 5
40
DP 6 20
DP 7
0 0
12
24
36
48
Hours
22
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 22 of 25
Figure 3. Peak
Compound
Glc/Gal Glucose/Galactose 2.1
β-D-Gal-(1↔1)-α-D-Glc + β-D-Gal-(1↔1)-β-D-Glc
2.2 (L)
β-D-Gal-(1→4)-D-Glc (Lactose)
2.3
β-D-Gal-(1→3)-D-Gal
2.4
β-D-Gal-(1→4)-D-Gal
2.5
β-D-Gal-(1→3)-D-Glc
2.6
β-D-Gal-(1→2)-D-Glc β-D-Gal-(1→4)-β-D-Gal-(1→6)-D-Glc
3.4
or β-D-Gal-(1→6)-β-D-Gal-(1→4/6)-D-Glc β-D-Gal-(1→4)-β-D-Gal-(1→6)-D-Glc
3.5
or β-D-Gal-(1→6)-β-D-Gal-(1→4/6)-D-Glc
3.6 + 3.7
β-D-Gal-(1→4)-β-D-Gal-(1→4)-D-Glc + β-D-Gal-(1→4)-β-D-Gal-(1→4)-Fru β-D-Gal-(1→4)-β-D-Gal-(1→3)-D-Glc
3.9
β-D-Gal-(1→4)-β-D-Gal-(1→2)-D-Glc 2.2 (L)
3.6 + 3.7
3.8
β-D-Gal-(1→3)-D-Gal
2.4
β-D-Gal-(1→4)-D-Gal
2.5
β-D-Gal-(1→3)-D-Glc
2.6
β-D-Gal-(1→2)-D-Glc
DP4-c
β-D-Gal-(1→4)-β-D-Gal-(1→6)-D
or β-D-Gal-(1→6)-β-D-Gal-(1→4/
β-D-Gal-(1→4)-β-D-Gal-(1→6)-D
or β-D-Gal-(1→6)-β-D-Gal-(1→4/
β-D-Gal-(1→4)-β-D-Gal-(1→4)-D
+ β-D-Gal-(1→4)-β-D-Gal-(1→4)-
3.8
β-D-Gal-(1→4)-β-D-Gal-(1→3)-D
3.9
β-D-Gal-(1→4)-β-D-Gal-(1→2)-D
DP6 DP7
DP5 DP6
DP5
3.6 + 3.7 DP4-d
3.9 DP4-b
DP4-a
3.5
2.3
DP3
2.1
3.4 2.4 2.5 2.6 3.5
2.2 (L)
Glc/Gal
3.8
3.4
Response(nC)
β-D-Gal-(1→4)-D-Glc (Lactose)
2.3
t0 t12 t24
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
Time (min)
ACS Paragon Plus Environment
18.0
20.0
t48 22.0 23
Page 23 of 25
Journal of Agricultural and Food Chemistry
µmol/mg substrate
Figure 4.
A) 15.0
lactate 10.0
succinate butyrate
5.0
propionate acetate
0.0 0
10
12
24
48
24
48
Hours
B) II) µmol/mg substrate
15.0
10.0
5.0
0.0 0
10
12
415
Hours
24
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 24 of 25
Table of Contents (TOC) Graphic
Oligosaccharide fermentation with piglet inocula Porcine milk oligosaccharides
Galacto-oligosaccharides
100
µmol/mg substrate
6
5
4 50 3
2
1
0
Remaining oligosaccharides (% )
7
0 0
10
12
24
48
0
10
12
24
48
Fermentation time (hours) Lactate
Succinate
Butyrate
Propionate
Acetate
pmo%
25
ACS Paragon Plus Environment