Hi. I'm Diego Navarro. I'm a Ph. D. student at the Stein Monogastric Nutrition
Laboratory at the University of Illinois. And today I'll be talking about the
concentration of energy in processed soybean and rapeseed products fed to pigs.

This is the general outline of my presentation for today. I'll start by giving a
brief overview of some of the soybean and rapeseed products fed to pigs. And
then I'll discuss the material and methods of this experiment, and then dive
into the results and the conclusions.

Let's start with some of the soybean products.

This is a simple illustration of how some of our soybean products are produced.
We start with the raw soybeans; we remove the hull to get our dehulled full fat
flakes, which we can then subject to heat treatment to get full fat soybean
meal, or solvent oil extraction to remove the oil to get defatted flakes, which
we then toast and grind to get our conventional soybean meal. Defatted flakes
can also undergo low heat vacuum drying to get white flakes. We remove the
soluble carbohydrates from the white flakes to get our traditional soy protein
concentrate.

So, what is soybean meal? Soybean meal is the byproduct of the soybean oil
industry, and it is widely used in swine diets, mainly because of its excellent
amino acid profile, which is high in lysine and tryptophan, which is why it
complements the amino acid profile of corn. 

However, there are several antinutritional factors found in soybean meal. We
have antigenic proteins such as trypsin inhibitors, lectin, glycinin, and
β-conglycinin. However, we usually see low levels of trypsin inhibitors and
lectins in the final product because of the heat treatment used to produce
soybean meal. We also have oligosaccharides that are stachyose, raffinose, and
verbascose, as well as some phytic acid. These antigenic proteins trigger a
transient hypersensitivity response in young pigs, which hinders the absorptive
ability of the small intestine, thus limiting the inclusion rate of soybean meal
in diets fed to young pigs.

However, it's been shown that these negative effects are reduced if soybean meal
is replaced with fermented soybean meal or enzyme treated soybean meal. Enzyme
treated soybean meal is soybean meal that undergoes a fermentation process, and
is then treated with an enzyme preparation, and is subsequently heat treated to
inactive its residual enzymes. The main goal of enzyme treatment is to reduce
the levels of antigenic proteins, specifically β-conglycinin, because this is
more resistant to digestion. Because of the reduction of antinutritional
factors, this results in an increased crude protein and amino acid
concentration, which makes enzyme treated soybean meal a suitable protein source
in diets fed to young pigs.

We also have what we call extruded soybean meal. Extrusion involves high heat
and high pressure processes, which denatures proteins into smaller peptides and
gelatinizes starch, which increases protein and starch digestibility in the
resulting meal.

And now, let's move on to our rapeseed products.

00-rapeseed is the low erucic and low glucosinolate variety of our traditional
rapeseed. In North America, this is also referred to as canola meal. Rapeseed
meal also contains a desirable amino acid profile which is high in our sulfur
containing amino acids. However, it also contains several antinutritional
factors, which include glucosinolates, tannins, and sinapine. And because the
hull is not removed in the processing of rapeseed meal, it contains a high fiber
concentration with up to three times more fiber than soybean meal.

There are two main oil extraction procedures in the processing of rapeseed.
Solvent extraction results in the conventional 00-rapeseed meal. The mechanical,
or expeller, extraction results in 00-rapeseed expellers.

These are the test ingredients that were used in this experiment. We had two
sources of enzyme treated soybean meal, an extruded soybean meal that was
subsequently fortified with an enzyme treatment, a source of soy protein
concentrate, conventional soybean meal, conventional 00-rapeseed expellers, and
a fermented co-product mixture containing fermented rapeseed meal, wheat, soy
molasses, and potato peel. Now, this product came to be because if fermentation
increased the quality of soybean meal, then maybe fermentation of rapeseed meal
with other components may also increase its digestibility. These ingredients are
commercially available in Denmark, with the first source of enzyme treated
soybean meal also marketed here in the U. S.

For the nutrient composition of the test ingredients on a dry matter basis, we
have the test ingredients in the columns. For crude protein, we observed an
increased crude protein concentration in the processed soybean products compared
to the conventional soybean meal. We also observed a similar concentration of
crude protein between the rapeseed expellers and the fermented co-product
mixture, but both had less crude protein compared to the soybean products. There
was a similar concentration of acid hydrolyzed ether extract between the soybean
products, and we observed the highest fat content in the rapeseed expellers due
to the processing of this product.

We also expected a high concentration of NDF in the rapeseed products because
the hull is not removed in the processing of rapeseed expellers, and because of
the other fibrous components that were added in the fermentation co-product
mixture. However, it was surprising to see a high concentration of NDF in the
soy protein concentrate, which suggests that soy hulls may have been added back
to this ingredient, which makes it different from traditional sources of soy
protein concentrate. Now, for the gross energy on a kcal/kg dry matter basis, we
also observed a numerically higher GE content in the processed soybean products
compared to conventional soybean meal, and we also expected a high GE content in
the rapeseed expellers due to the high residual oil content.

Now, we look at the levels of sucrose in the soybean products. We have our
soybean products on the x axis and percent on the y axis. The color of the bars
representing each of the test ingredients will remain the same throughout the
rest of the presentation. We observed a decrease in the concentration of sucrose
in our processed soybean products. And this is mainly because of enzyme
treatment. However, enzyme treatment was not as effective in fermenting sucrose
in the second source of enzyme treated soybean meal and the extruded soybean
meal compared with the first source of enzyme treated soybean meal.

Similarly, looking at the levels of oligosaccharides, we observed a decreased
concentration of stachyose and raffinose in the first and second sources of
enzyme treated soybean meal. But again, enzyme treatment was not as effective in
fermenting these oligosaccharides in the second source of enzyme treated soybean
meal compared with the first source of enzyme treated soybean meal.

So the objective of this experiment was to determine the concentrations of
digestible and metabolizable energy in soybean products and 00-rapeseed
co-products.

For the materials and methods of this experiment, 64 barrows of the initial body
weight of about 20 kg were used and placed in metabolism cages. There was a five
day adaptation period followed by five days of fecal and urine collection. The
experiment was set up as a randomized complete block design with eight
treatments and eight replicates per treatment.

This is the ingredient composition of the experimental diets. A diet containing
97% corn was used as the basal diet, and an additional seven diets with corn
plus each of the test ingredients partially replacing corn were formulated. The
inclusion level of each of the test ingredients are not the same because these
diets were formulated to be isonitrogenous.

The difference procedure was used to calculate for DE and ME. And data were
analyzed using the Mixed procedure of SAS, with diet as the fixed effect and
group as the random effect.

Moving on to the results of the experiment, for the apparent total tract
digestibility, or ATTD, of gross energy, we observed that the conventional
soybean meal had the greatest ATTD of GE, but was not different from corn. There
were no differences in the ATTD of GE between the processed soybean products,
but all of them were less than the conventional soybean meal. And this is mainly
because of the disappearance of sucrose in the resulting meal. The ATTD of GE
between rapeseed expellers and fermented co-product mixture were not different,
but both were less than all of the soybean products.

For the concentration of digestible energy on a kcal/kg dry matter basis, we
observed that the second source of enzyme treated soybean meal had less DE
compared with the first source of enzyme treated soybean meal, extruded soybean
meal, and soy protein concentrate, but was not different from the conventional
soybean meal. There were no differences in DE between the rapeseed expellers and
the fermented co-product mixture, but both had less DE compared with the soybean
products.

Similarly, for the concentration of metabolizable energy, we also observed that
the second source of enzyme treated soybean meal had the least concentration of
ME between all of the soybean products. The difference between the concentration
of ME between the first and second sources of enzyme treated soybean meal may be
due to the differences in the processing of these products, or variability in
the sources of soybean meal. We also observed that the concentration of ME was
not different between the first source of enzyme treated soybean meal, and the
soy protein concentrate. And this indicates that enzyme treatment does not
decrease the concentration of ME, even with the removal of sucrose and
oligosaccharides in the resulting meal. We also observed a higher concentration
of ME in the conventional soybean meal compared with corn. and this has been
observed in several experiments conducted at the University of Illinois. And
this suggests that book value s for energy in conventional soybean meal may be
underestimated. There were no differences in the concentration of ME in rapeseed
expellers and fermented co-product mixture, but both were less than the soybean
products.

In conclusion, the concentrations of digestible and metabolizable energy were
different among processed soybean products. And the process used to produce the
second source of enzyme treated soybean meal was less efficient in maintaining
the concentrations of energy compared with the first source of enzyme treated
soybean meal. And lastly, the concentration of digestible and metabolizable
energy in the soybean products were greater than in the 00-rapeseed expellers
and the fermented co-product mixture.

With that, I would like to acknowledge the Danish Pig Research Centre for
funding this research project.

And if you would like to know more about swine nutrition, you can visit our
website at nutrition.ansci.illinois.edu. Thank you for your attention.