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. 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. 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. 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. 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. 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. For our results… 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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.