Use of feed technology to improve the nutritional value of feed ingredients fed to pigs

Use of feed technology to improve the nutritional value of feed ingredients fed to pigs


Hi, everybody. My name is Oscar Rojas. I am
a Ph. D. student working with Dr. Hans Stein. And today, I will talk about the use of feed
technology to improve the nutritional value of feed ingredients fed to pigs. This is the take home message of my presentation.
The first point is that reduction of particle size of corn increased energy and starch digestibility.
The second point is that it is possible to reduce fat addition in diets without reducing
growth performance or carcass characteristics. The third point is that energy utilization
may be improved by pelleting, extrusion, or the combination of both systems in diets fed
to pigs. And the last point in our presentation today is that the use of cellulase may increase
the energy value of DDGS. This is the outline of this podcast. I will
start with a brief introduction about some ingredients that are commonly used in diets
fed to pigs. And then we also review some types of feed processing. Then, we will move
on to a summary of 7 experiments that related to energy and nutrient digestibility and growth
performance. And this part will be divided into sections. The first section is related
to corn particle size. The second section is related to the use of different technologies
– either extrusion, pelleting, or a combination of both systems – in diets with different
levels of fiber. and the third section will be related to the use of chemicals, enzymes,
or extrusion technology to improve the nutritional value of DDGS. And then we’ll finish this
presentation with some general conclusions. In this slide, we have our pig, and this is
our system. In all the systems, we have an input and an output. As an input, we have
our diets, and as a swine nutritionist, we can control our input. So we can decide what
type of ingredients we want to include in our diets and at which concentrations they
are going to be included. And also we have our output, that in this case are the feces.
And sometimes, we have the opportunity to use different feed technologies, such as grinding,
extrusion, pelleting, chemicals, or enzymes, either by themselves or in combination, to
our diets. And if we fail to use any of those technologies, or if we fail to include the
right concentration of ingredients in our diets, we are going to increase the excretion
of nutrients in our system, in this case the feces. And this means that we are going to
lose money, and also we are going to contaminate the environment with those nutrients that
are excreted. In this slide, we observe the neutral detergent
fiber in different ingredients that are used in diets fed to pigs. We have corn, soybean
meal, DDGS, and soybean hulls. We observe here that when we include corn and soybean
meal in our diets, our NDF concentrations range between 8 and 10%. However, when we
move to an alternative ingredient, such as DDGS and soybean hulls, we increase the concentration
of fiber in our diets. This means that as we increase the concentration of fiber in
our diets, energy and amino acid digestibility is reduced, and therefore this generates an
opportunity for us to use different technologies to increase the nutritional value of that
fiber. When we use different feed technologies, we
have some advantages. Some of them are: increases availability of nutrients; decreases excretion
of nutrients; we may observe an increase in performance; we also may observe an increase
in gelatinization of the starch; and also we can observe an improvement in feed handling. We also may observe some disadvantages when
we decide to process our diet. The first one is that processing will add costs to our diets.
Excess of heat will reduce the digestibility and the concentration of lysine. You could
also get retrogradation of starch, and this means that we generate resistant starch, which
will decrease the digestibility of energy. So, the overall objective of this presentation
is to determine the effect of different processing techniques on energy and nutrient digestibility
of diets and ingredients fed to pigs. Let’s start with the first part of this podcast,
that is related with corn particle size. The objective of the first two experiments
was to determine the concentration of DE and ME and the digestibility of phosphorus, amino
acids, and starch in corn grain that was ground to different particle sizes and fed to growing
pigs. It has been recommended that corn may be ground
to a particle size between 600 and 650 microns. This could be accomplished by the use of either
roller mills and hammer mills. However, now the industry is trying to move to a combination
of both systems, trying to increase grinding efficiency and to reduce variability. However, there are some problems related when
we try to reduce the particle size. The first problem that we may observe is that as we
try to reduce the particle size of corn, there is an increase in electricity costs at the
feed mill, which will increase the energy costs. Also, as we reduce the particle size,
we may observe a reduction in flowability. But, if we decide to pellet our diets, this
is not going to be the case. And also, it has been reported than as we reduce the particle
size of corn, we may observe some ulcers in the stomachs of those pigs. So we started with a single batch of corn.
This corn was ground using a roller mill to a mean particle size of 2000 microns. Then,
we used hammer mills with different screens to obtain 4 different particle sizes of corn:
865 microns, 677 microns, 485 microns, and 339 microns. In this slide, we observe the apparent ileal
digestibility of starch. And we observe here that as we reduce the particle size of corn,
from 865 microns to 339 microns, apparent ileal digestibility increased linearly. And when we look at apparent total tract digestibility
of gross energy, we observe the same pattern as we observed for the apparent ileal digestibility
of starch. As we reduce the particle size of corn, we observe that the digestibility
of gross energy increased. Here, we observe the concentration of ME in
dry matter basis, and we observe also that as we reduce the particle size, the concentration
of ME increases. And the reason of this is that as we increase the digestibility of starch,
then we’ll increase the concentration of ME as we reduce the particle size of corn. And it’s important to mention that reduction
of particle size of corn did not have an effect on phosphorus and amino acid digestibility. So what are the implications of these two
experiments? Because of the increased ME in corn ground to a smaller particle size, it
may be possible to reduce fat addition in diets if corn is ground to a smaller particle
size. So based in our previous result, we wanted
to test the hypothesis that the addition of dietary lipids can be reduced as corn particle
size is reduced without affecting growth performance or carcass characteristics. For this experiment, we used 72 pigs with
initial body weight of 32.0 kg ± 1.58 kg. We had 36 gilts and 36 barrows that were housed
individually. We have 18 pigs per treatment. And this experiment was designed to contain
3 phases: the first phase was between 32 and 62 kg, the second phase was between 62 and
94 kg, and the last phase was between 94 to 129 kg. In this slide, we observe how we formulated
those diets. As I mentioned before, we have 3 phases: Phase 1, Phase 2, and Phase 3. For
Phase 1 diets, as we reduced the particle size of corn from 865 microns to 339 microns,
we reduced the concentration of oil from 3.6 to 2.0. And the reason of this was to maintain
the concentration of ME among diets – in this case, 3,396 kcal/kg. And we used the
same approach to formulate Phase 2 and Phase 3 diets. Here, we observe the overall growth performance
for this experiment. We have average daily gain, average daily feed intake, and gain:feed
ratio. And we observe here that reduction of particle size did not affect average daily
gain or average daily feed intake. However, as you observe here, as we reduced the particle
size of corn, gain:feed ratio is reduced. Here, we observe the hot carcass weight in
kg. We observe that as we reduced the particle size of corn, hot carcass weight is not affected. However, when we calculate dressing in percentage,
we observe that as we reduced the particle size of corn, the dressing percentage increased
linearly. And the reason of this is that pigs that were fed a diet containing corn ground
to 865 microns, the GI tract of those pigs were heavier compared with pigs that were
fed a diet containing corn that was ground to 339 microns. And if you remember, I mentioned before that
as we reduced the particle size of corn, we observed that gain:feed decreased linearly.
However, we recalculate that gain:feed ratio, but now based on hot carcass weight. And we
observe here that reduction of particle size did not affect gain:feed among treatments. In this slide, you can see the concentration
of short chain fatty acids in cecal contents. We have acetate, propionate, and butyrate.
And you observe that as we reduced the particle size of corn, we reduced the concentration
of each of those short chain fatty acids. And the reason of this is that as we reduce
the particle size of corn, there are less nutrients coming in to the large intestine,
and therefore there is less fermentation. We also measured pH in different contents:
ileal content, cecal content, and colon content. And we observe here that there is a greater
pH as we reduce the particle size of corn in cecal contents and in colon contents. This
indicates that, as we reduce the particle size, there is less fermentation, and therefore
we observe a greater pH in those samples. We also were aware that as we reduced the
particle size, we may observe some lesions in the stomachs of the pigs. In this slide,
we observe the different sections of the stomachs of the pig. We have the esophageal region,
cardiac region, fundic region, and pyloric region. And as you observe, the cardiac region,
fundic region, and pyloric region have a mucus, and that mucus protects those sections of
the stomachs against the hydrochloric acid. However, this is not the case for the esophageal
region. And that’s why, as we reduce the particle size, it has been proposed that that region
is affected. In this slide, we observe the frequency of
lesions in the esophageal region in those stomachs. We considered those stomachs in
orange; blue as minor lesions; medium, green; and red, major lesions. For example, for the
diets containing corn ground to 865 microns, we observe that 50% of those stomachs were
considered normal. And 20% of those stomachs had some level of lesions, minor lesions,
and 20% were considered medium lesions. However, as we reduced the particle size of corn, we
observed for example in the case of 339 microns, that none of those stomachs were considered
normal; and in fact, almost 40% of those stomachs had minor lesions, 20% were considered medium
lesions, and almost 35% of those stomachs had major lesions. It’s important to mention
that none of those stomachs had ulcers; they just had some level of parakeratinization. In this slide, we can see the esophageal lesion
score. Zero means that no lesions were observed, and 10 indicates ulcers. We observe here that
as we reduced the particle size of corn, the lesion score increased linearly. So, the implication of these growth performance
experiments are that it is possible to reduce fat addition in diets if corn ins ground to
a smaller particle size without affecting growth performance or carcass characteristics.
And also, we need to be aware that as we reduce the particle size, we may observe some level
of lesions in the stomachs, and also we may observe problems with diet flowability in
our feeders. Once we conduct the growing-finish experiment,
we wanted to test if we may observe the similar response using weanling pigs. So, we wanted
to test the hypothesis that caloric utilization of corn fed to weanling pigs is increased
if particle size of corn is reduced. In this slide, we observe the soybean oil
concentration in diets for two different experiments. For the first experiment, we wanted to maintain
constant the concentration of corn and the concentration of soybean oil among diets.
And that’s why we have different values for ME concentration. And that’ s why we observed
that as we reduced the particle size of corn, ME is increased. However, for the experiment
2, we wanted to maintain constant the concentration of ME in our diets, in this case 3000-3413
kcal/kg. And the way how we accomplished this was using the same approach that we used for
the growing-finishing experiment. So what we did was reduce the concentration of soybean
oil as we reduced the particle size of corn in our diets. Here, we observe the growth performance data
for Experiment #1. And we observed that as we reduced the particle size, gain:feed ratio
increased linearly. And the reason of this is that average daily feed intake is reduced.
And what this means is that pigs that were fed a diet containing corn ground to 339 microns,
they don’t need to eat as much as pigs fed diets containing corn ground to 865 microns
because those pigs will get more energy in that corn that was ground to a smaller particle
size. For the second experiment, we wanted to maintain
the energy constant. And by doing this, we were assuming that we will obtain similar
gain:feed ratio among treatments. However, as you can see, this was not the case. We
observed that as we reduced the particle size, there is a linear increase in gain:feed, and
we were not expecting this because we formulated those diets to have the same concentration
of ME among diets by reducing the concentration of soybean oil as we reduced the particle
size of corn. And we believe that the reason of this observation is that those younger
pings were not able to absorb the fat coming from the soybean oil, and that’s why those
pigs were not able to maintain similar values of gain:feed. We also measured pH in colon contents for
those two experiments. And we observed the same pattern as we observed for the growing-finishing
experiment. We observed that as we reduced the particle size of corn, there is a linear
increase in the pH , indicating that there is less fermentation as we reduce the particle
size of corn. So the implication for those two experiments
are that if diets contain corn ground to a particle size of 339 microns, rather than
a greater particle size, gain:feed of pig is improved, and also inclusion of dietary
fat may be reduced if corn is ground to a finer particle size. The general conclusion for the first part
of this podcast is that there is an increase in apparent ileal digestibility of starch
and the concentration of DE and ME as we reduce the particle size of corn. And also, it is
possible to reduce the addition of lipids in the diets if corn is finely ground without
affecting growth performance or carcass characteristics. So now, let’s move on to the second section
of this podcast, looking at the effect of extrusion and pelleting, or the combination
of both systems, on energy and nutrient digestibility in diets with different levels of fiber fed
to pigs. The objective of this experiment was to test
the hypothesis that pelleting and extrusion of diets, either alone or in combination,
will improve the nutrient and energy digestibility, and this response is greater in high fiber
diets than in low fiber diets. For this experiment, we have 3 different levels
of fiber: low level, medium level, and high level. In the case of low level of fiber,
this diet was a combination between corn and soybean meal. In the case of medium level
of fiber, we included 25% of DDGS. And in the case of high fiber diets, we included
corn, soybean meal, 25% of DDGS, and on top of that, we add 20% of soybean hulls. So now let’s see how we process those diets.
We have 4 different types of processing. If we take, for example, the low level of fiber,
corn-soybean meal diet, we mix a diet, and we call that the meal diet. Also, if we pellet
the diet, we call it the pelleted diet. We also extrude the corn-soybean meal diet, and
we call that the extruded diet. And if we first extrude it and then pellet it, we call
that our last treatment, extruded and pelleted diet. Pellet of the diet was at 85 degrees
and extrusion of the diet was at 115 degrees Celsius. Here, we observe the apparent ileal digestibility
of starch. And here, we are looking at the effect of processing. As we process the meal
diet, either with pelleting, extrusion, or a combination of both systems, we observe
that the digestibility is increased compared with the meal diet. Now, when we look at the apparent ileal digestibility
of lysine, we observe that digestibility of lysine is improved in pelleted diets, extruded
diets, or the combination of both systems compared with the meal diet. However, the
extruded and pelleted diet, in the case for digestibility of lysine, was not different
from the extruded or the pelleted diet. Now, when we look at the apparent ileal digestibility
of threonine, we observe the same pattern as the previous slide. As we process the meal
diet, either with pelleting, extrusion, or the combination of both systems, we observe
that the digestibility of threonine is improved compared with the meal diet. And it’s important to mention that for all
the indispensable amino acids, the apparent ileal digestibility was greater for pelleted,
extruded, or extruded and pelleted diets than for the meal diets. Here we are looking at the apparent total
tract digestibility of gross energy. We observe here that the pelleted diet and the extruded
and pelleted diet have greater digestibility compared with the meal diet. However, they
were not different than the extruded diet. In this slide, we observe the ME concentration
on dry matter basis. And in this case, we observe and interaction between fiber and
the type of process. We have in the blue bars, low level of fiber; orange bars, the medium
level of fiber; and the red bar represents high level of fiber. And we observe, first
of all, that as we increase the concentration of fiber in the diets, there is a reduction
in the concentration of ME in our diets. We also observed that as we process the diet,
either with pelleting, extrusion, or the combination of both systems, the concentration of ME increased
compared with the meal diet for low and high fiber diets. But this was not the case for
diets containing medium level of fiber. And also, we observe here that the increase in
ME concentration was greater in high fiber diets than in low fiber diets. So the implication of these experiments is
that ileal digestibility of amino acids and starch is improved by pelleting, extrusion,
or the combination of both technologies, and also that extrusion improved energy value
to a greater extent in high fiber diets than in low fiber diets. And in our last section of this podcast is
the effects of chemicals, physical or enzymatic treatments on the concentration of ME and
the digestibility of energy in DDGS fed to pigs. The objective of this experiment was to determine
the effects of physical, chemical, and enzymatic treatments on the concentration of ME in DDGS. For this experiment, we start with a batch
of DDGS, and this batch was divided in 6 sub-batches. The first batch was called untreated DDGS,
the second batch was extruded, the next 2 batches were treated with either calcium oxide
or sodium hydroxide, and the last 2 batches of DDGS were treated with the addition of
cellulase or hemicellulase. Here, we observe the concentration of ME in
dry matter basis. And we observe here that when treat DDGS either with extrusion, sodium
hydroxide, or hemicellulase, we did not change the concentration of ME compared with the
untreated DDGS. However, when we treat the DDGS sample with cellulase enzyme, we observe
that the concentration of ME increased compared with the untreated DDGS. So the conclusion for this experiment is that
cellulase treatment was effective in improving the concentration of ME in DDGS, and hemicellulase,
extrusion, sodium hydroxide, or calcium oxide treatments of DDGS did not consistently improve
the concentration of ME or the apparent total tract digestibility of gross energy in DDGS. So the overall conclusions for these experiments
is that the use of fine grinding, enzyme addition, extrusion, or of pelleting may positively
influence the energy and nutrient digestibility in ingredients and diets fed to pigs. So once again, to remind you, the four important
points of this presentation: reduction of particle size of corn increased energy and
starch digestibility; it is possible to reduce fat addition in diets without reducing growth
performance; energy utilization may be improved by pelleting, extrusion, or the combination
of pelleting and extrusion in diets fed to pigs; and the use of cellulase may increase
the energy value of DDGS. Thank you for your attention.

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