Slide 1

Hi. My name is Dr. Sarah Cervantes-Pahm, and I am here to present to you one
of our studies entitled, "The effect of novel carbohydrates on apparent
ileal disappearance and apparent total tract disappearance of gross energy
and nutrients in semi-purified diets fed to pigs." This experiment was
presented at the American Society of Animal Science Midwest Conference in
2011 under Abstract #232.

Slide 2

So, for our introduction: Novel carbohydrates are indigestible in the small
intestines. And for that reason, they are considered dietary fibers. And
they are intended to be added to food and beverages to increase the dietary
fiber intake in humans. In a previous experiment, we have measured the
caloric value of four novel carbohydrates. So in this experiment, we want to
determine the effect of adding novel carbohydrates to the diets in pigs.

Slide 3

Therefore, the objective of this experiment was to determine the effect of
novel carbohydrates on the apparent ileal disappearance and apparent total
tract disappearance of gross energy and nutrients in semi-purified diets
containing cellulose and four novel carbohydrates fed to growing pigs.

Slide 4

We used six carbohydrates in this experiment. We used maltodextrin as a
positive control, and we used maltodextrin because it's a very digestible
form of carbohydrate. We also used cellulose as a negative control. We chose
cellulose because it is a carbohydrate that is well-characterized as an
insoluble and poorly-fermentable fiber. The novel carbohydrates that we used
for this experiment were also the novel carbohydrates that we used for our
previous experiment. And these novel carbohydrates were the two types of
insoluble fiber, resistant starch 60 and resistant starch 75 (the 60 and the
75 denoting the concentration of TDF in these fiber ingredients). And two
types of soluble fibers: soluble corn fiber 70 and pullulan.

Slide 5

Our hypothesis for this experiment is that the apparent ileal disappearance
of gross energy and crude protein will be lower in the diets containing
cellulose and novel carbohydrates compared with the maltodextrin-casein
control diet.

Our second hypothesis is that, although dietary fibers are not digestible in
the small intestines, we believe that a fraction of the TDF in the diet
disappears in the small intestines.

Slide 6

So for our materials and methods, we used a total of 24 pigs that were
fitted with ileal cannulas. We prepared six diets. Diet 1 was our control
diet, and it was basically a maltodextrin-casein based diet. For diets 2-6,
we replaced 10% maltodextrin with 10% of cellulose or each of the novel
carbohydrates. The novel carbohydrates were therefore the only source of TDF
in the diet.

Slide 7

For our results...

Slide 8

This graph presents the concentration of TDF in the ingredients.  I would
like to point out that the analytical procedure that was used to measure TDF
in this experiment is AOAC method 991.43, which you could see in the lower
right-hand corner of your slide. And you would see later on that this method
has some limitations.

Based on this method, maltodextrin -- in the red bar -- contained 1.2% TDF.
The occurrence of a small amount of TDF is unexpected because maltodextrin
is a very digestible carbohydrate.  The presence of a small amount of TDF in
maltodextrin may indicate that maltodextrin may only be 99% digestible or
that this value reflects a limitation of the AOAC method 991.43 for TDF
analysis.

Cellulose -- in the blue bar -- contained 100% TDF, RS 60 -- in the green
bar -- contained 62.9% TDF, and RS 75 -- in the yellow bar -- contained
75.6% TDF.   

Soluble corn fiber 70 -- in the [light] blue bar -- only contained 10% TDF
using this method.  This is one of the limitations of AOAC 991.43. Because
soluble corn fiber is composed of low molecular weight carbohydrates that
are soluble in ethanol, this method poorly recovers the dietary fiber
fractions in soluble corn fiber resulting to low TDF values. However, when
AOAC method 2001.3 is used, soluble corn fiber 70 has at least 70% TDF. This
indicates that AOAC method 991.43 is not the suitable TDF method to measure
the concentration of TDF in soluble corn fibers.

Slide 9

This graph shows the effect of the addition of cellulose or the novel
carbohydrates in the diets on the AID of gross energy.

The AID of gross energy in the maltodextrin control diet is 96.8% and we
could see that the addition of cellulose and the novel carbohydrates in the
diet reduced the AID of gross energy to varying degrees.  

Slide 10

Among the insoluble fibers, the addition of cellulose reduced the AID of
gross energy to a greater extent (at 11 percentage units) than the addition
of either RS 60 or RS 75 (which reduced the AID of gross energy by 6.3 to
8.2%). However, between the resistant starches, RS 75 reduced the AID of
gross energy more than RS 60. 

Slide 11

The addition of soluble corn fiber 70 and pullulan to the diet reduced the
AID of gross energy to a similar extent. There was no difference in the AID
of gross energy among RS 60, soluble corn fiber, and Pullulan.

Slide 12

Looking at the effect of adding cellulose or novel carbohydrates on the
digestibility or disappearance of carbohydrates, we could see from this
graph that the addition of cellulose and the novel carbohydrates reduced the
AID of carbohydrates in the diets.

This indicates that the reduction in the ileal digestibility of gross energy
in diets added with cellulose or the novel carbohydrates is because of the
reduction in the ileal digestibility of carbohydrates in the diets.

And this is important because a reduced ileal digestibility of carbohydrates
implies that less energy is absorbed as glucose and this physiological
effect is specially important to manage blood sugar concentrations,
especially in diabetic patients.

Slide 13

We also look at the effect of adding cellulose or novel carbohydrates in the
ileal digestibility of crude protein in the diets. As we can see from this
graph, the addition of cellulose and pullulan, but not RS 60, RS 75, and
soluble corn fiber 70, reduced the protein digestibility in the diet. A
reduction in the digestibility of protein is an undesirable characteristic
in a fiber ingredient. Therefore it is important to choose a fiber
ingredient that can reduce carbohydrate digestibility, but not protein
digestibility. 

Slide 14

We tried to explain the reduction in the AID of CP in the diets added with
cellulose and pullulan. If you look at the values at the bottom, these
values are the water binding capacity of the diets. And what we noticed is
that diets containing cellulose and pullulan had a greater water binding
capacity than diets containing RS 60, RS 75, soluble corn fiber, or
maltodextrin. Therefore, we believe that the reduction in the crude protein
digestibility in diets containing cellulose and pullulan is because of its
greater capacity to bind water.

Slide 15

So for our second hypothesis, and that is that a fraction of the TDF in the
diet will disappear in the small intestines, we determined the fraction of
TDF that disappears in the different segments of the digestive tract.

Slide 16

In this experiment, we observed a high SEM which makes the data less
sensitive to pick up differences among treatment means.

However, from this graph, we could see that the AID of TDF in the
maltodextrin diet was negative. This indicates that some endogenous
compounds were analyzed as TDF, because the concentration of TDF in the
ileal digesta was more than what was consumed from the maltodextrin diet.

The AID of TDF in cellulose is only 15.7%. The disappearance of TDF in RS 60
and pullulan diet was greater than in the cellulose diet at 44 and 49%,
respectively.

We also observed a negative value for the disappearance of TDF in the
soluble corn fiber diet. Considering that the method 991.43 is not suitable
to measure TDF in soluble corn fiber it is difficult to draw conclusions on
the ileal disappearance of TDF from the soluble corn fiber diet.

Slide 17

Looking at the apparent total tract disappearance of TDF, the apparent total
tract disappearance of TDF in the maltodextrin diet is again negative,
strongly suggesting that some endogenous compounds were analyzed as TDF.

35% of the TDF in cellulose disappeared over the total tract indicating that
cellulose is a poorly fermentable fiber, whereas the TDF in RS 60 and
pullulan disappeared at about 56 and 49% respectively.

The negative disappearance of TDF in the soluble corn fiber diet is
difficult to interpret. Not only because of the analytical issue involved
with soluble corn fiber, but because of the endogenous losses that possibly
could be analyzed as TDF. But relative to the disappearance of TDF in the
maltodextrin diet, the lesser negative value of disappearance of TDF in the
soluble corn fiber diet suggest that the fiber in soluble corn fiber is not
fermentable. However, this conclusion is not consistent with reports from
literature indicating the the fiber in soluble corn fiber is fermentable.

Therefore, we decided to calculate the amount of endogenous compounds that
was analyzed as TDF.

Slide 18

The endogenous loss of TDF at the ileum was 25.25 g/kg dry matter intake,
and over the total tract, the endogenous loss of TDF was calculated at 42.87
g/kg dry matter intake. We believe this is the first reported value of
endogenous loss of TDF.

Using this values, we removed the influuence of endogenous compounds that
were analyzed as TDF, and we calculated for the standardized ileal
disappearance of TDF and the standardized total tract disappearance of TDF.

Slide 19

We could see from this slide that the SID of TDF in the soluble corn fiber
diet is not anymore negative. And we could also see that the SID of TDF in
the cellulose diet is at 35.8%  and was less than the SID of TDF in RS 60,
soluble corn fiber, and pullulan. The SID of RS 75 was not different from
that of cellulose.

This graph also indicates that a substantial amount of TDF -- approximately
55% if we do not include the value for soluble corn fiber -- disappears in
the small intestines.  Whether this disappearance is attributed or can be
attributed to the fermentation in the small intestines or to the solubility
of the fiber in the novel carbohydrates cannot be determined, and that is
something that needs to be explored and studied further.

Slide 20

This graph presents the standardized total tract disappearance of TDF in the
diets. And we could see that the STTD of TDF in cellulose is 68.8%, and the
STTD of TDF in RS 60, RS 75, and pullulan was not different from cellulose.
The STTD of RS 60, RS 75, and pullulan was also not different from each
other. So we could see from this slide that the disappearance of TDF in the
novel carbohydrates is quite substantial at 85% if we exclude the value for
soluble corn fiber 70.

Slide 21

So in conclusion, this experiment has shown that novel carbohydrates
included at 10% in the diet reduced the AID of gross energy by the reduction
in the AID of total carbohydrates. This experiment has also shown that the
addition of cellulose and pullulan -- but not RS 60, RS 75, and soluble corn
fiber 70 -- reduced the AID of crude protein. We have also observed that
some TDF disappeared in the small intestines, and we believe that some
endogenous compounds were analyzed as TDF.

Slide 22

Thank you for your attention. And if you want more information on swine
nutrition and feeds and feeding, we would welcome you to our website at
http://nutrition.ansci.illinois.edu. Thank you, and have a great day.