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 talk about amino acid
digestibility in processed soybean and rapeseed products fed to weanling pigs.

This is the general outline of my presentation. I'll give a brief background on
soybean products and rapeseed products. Then I'll present the materials and
methods before diving into the results and the conclusions of this experiment.

Let's start with some of our soybean products.

And now, a simple diagram of how some of our soybean products are produced. We
start with our raw soybeans, remove the hull to get dehulled full fat flakes,
which can then undergo either heat treatment to get full fat soybean meal, or
solvent oil extraction to get defatted flakes that will undergo toasting and
grinding to get our conventional soybean meal. Soybean meal is widely used in
swine diets because of its excellent amino acid profile that is high in lysine
and tryptophan. We can also subject defatted flakes to low heat vacuum drying to
get white flakes. The soluble carbohydrates are extracted from the white flakes
to get our soy protein concentrate.

There are also several antinutritional factors found in soybean meal. There are
also antigenic proteins that include trypsin inhibitors and lectins, but we are
no longer concerned about these because they are usually found in low levels in
the resulting meal due to heat treatment. also, we have glycinin and
β-conglycinin, as well as oligosaccharides that are stachyose, raffinose, and
verbascose. We also have some levels of phytate. Now, these antigenic proteins
trigger a transient hypersensitivity response in young pigs that hinders the
absorptive ability of the small intestine, thus limiting the inclusion rate of
soybean meal in diets fed to young pigs. However, it has been shown that these
negative effects are reduced if soybean meal is replaced with fermented or
enzyme-treated soybean meal.

Soybean meal can be processed further by fermenting, and subjecting it to enzyme
treatment, that will result in what we call enzyme-treated soybean meal.

Enzyme-treated soybean meal is produced by fermenting soybean meal in the
presence of yeast, and is subsequently treated with an enzyme preparation before
it is heat treated to inactive residual enzymes. The goal of enzyme treatment is
to reduce the levels of β-conglycinin because it is more resistant to digestion.
Enzyme treatment also reduces the concentrations of sucrose and
oligosaccharides, thus resulting in an increase in crude protein and amino
acids, making enzyme-treated soybean meal a suitable protein source in diets fed
to young pigs.

Now let's move on to our 00-rapeseed coproducts.

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

The type of the oil extraction procedure that is used in the processing of
rapeseed results in different products. Solvent extraction results in
00-rapeseed meal, whereas mechanical or expeller extraction results in rapeseed
expellers, or what we call cold-pressed rapeseed cake.

Now, I will introduce the test ingredients used in this experiment, represented
by the abbreviations in white. We have two sources of enzyme-treated soybean
meal, an extruded soybean meal that was subsequently treated with an enzyme
preparation, soy protein concentrate, conventional soybean meal, conventional
00-rapeseed expellers, and a fermented co-product mixture containing fermented
00-rapeseed meal, wheat bran, soy molasses, and potato peel.

This table shows the analyzed nutrient composition of the test ingredients. The
dry matter content ranged from 93 to 87%. The crude protein content of the
processed protein products were numerically greater than in the conventional
soybean meal. The crude protein content was similar between the two rapeseed
products, but were less than in the soybean products. The concentration of acid
hydrolyzed either extract was greatest in the rapeseed expellers, and this was
expected due to the processing used to produce this product. We also expected
both rapeseed products to have the greatest neutral detergent fiber
concentration, because the hull is not removed in the processing of the rapeseed
expellers, and because of the other fibrous products that were fermented with
the rapeseed meal in the fermented co-product mixture. However, it was
surprising to see a high NDF content in the soy protein concentrate, indicating
that soy hulls may have been added to this product, making it different from
traditional sources of soy protein concentrate. The gross energy of the
processed soybean products were numerically greater than in the conventional
soybean meal, and we also expected the high concentration of gross energy in the
rapeseed expellers because of its high residual oil content.

And so the objective of this experiment was to determine the standardized ileal
digestibility, or SID, of amino acids in soybean products and rapeseed
co-products fed to weanling pigs.

For the materials and methods of this experiment, 27 ileal cannulated weanling
barrows of initial body weight of around 9.3 kilograms were used. The
experimental design was set up as a 9x5 Youden square design, with nine pigs and
five periods in each square. In each square, six pigs were assigned to the
nitrogen-free diet, and three pigs were assigned to the diet containing the test
ingredient, to get a total of 30 replicates for the nitrogen-free diet and 15
replicates for each of the test ingredients.

This slide shows the diet composition of the experimental diets, with diet on
the columns and ingredients on the rows. The first and second sources of
enzyme-treated soybean meal, as well as the extruded soybean meal, were included
at 35%, the soy protein concentrate at 30%, the conventional soybean meal, the
rapeseed expellers, and the fermented co-product mixture at 40% of the diet.
Soybean oil, cornstarch, and equal amounts of sucrose were included, and
vitamins and minerals were supplemented to meet the requirements of the animals.

The SID of amino acids was calculated, and the data were analyzed using the
Mixed procedure of SAS with diet as the fixed effect and pig and period as the
random effect.

And now, let's look at the results of the experiment.

Let me take a moment to set up my slide. On the x axis, we have the test
ingredients. On the y axis, we have percent. Looking at lysine, the SID of
lysine in the conventional soybean meal was greater than in the second source of
enzyme-treated soybean meal, the rapeseed expellers, and the fermented
co-product mixture, but was not different from the first source of
enzyme-treated soybean meal, the extruded soybean meal, and the soy protein
concentrate. The decreased SID of lysine in the second source of enzyme-treated
soybean meal indicates that lysine may have been heat damaged in the process
used to produce this product. Also, the SID of lysine in the rapeseed expellers
was greater than in the fermented co-product mixture.

Looking at methionine, the SID of methionine in the first source of
enzyme-treated soybean meal was greater than in the soy protein concentrate, the
rapeseed expellers, and the fermented co-product mixture, but was not different
from the second source of enzyme-treated soybean meal, the extruded soybean
meal, and the conventional soybean meal. Again, the SID of methionine in the
rapeseed expellers was greater than in the fermented co-product mixture.

Looking at threonine, there was no difference in the SID of threonine across all
soybean sources, but was greater than in both rapeseed products. Again, the SID
of threonine in the rapeseed expellers was greater than in the fermented
co-product mixture.

And now looking at tryptophan, the SID of tryptophan in the first source of
enzyme-treated soybean meal was greater than the rapeseed expellers and the
fermented co-product mixture, but not different from the other soybean products.
Again, the SID of tryptophan in the rapeseed expellers was greater than in the
fermented co-product mixture.

And for the conclusions of this experiment, the processing of soybean meal
results in increased concentration of crude protein, and does not change the
digestibility of amino acids. The SID of amino acids was different among
processed soybean products, and lastly, the fermentation of a co-product mixture
results in decreased SID values compared with unfermented 00-rapeseed expellers
and soybean products.

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

If you'd like to know more about swine nutrition, you can visit our website at
nutrition.ansci.illinois.edu. Thank you.