Gut health: Master the 3 masters in animal
nutrition
Written by Kelly Vermeer, Product Manager Joosten Young Animal Nutrition. References available
upon request.
Worldwide there is an increasing attention to optimize gut health. Understanding the three
masters - carbohydrates, protein and fat - is crucial in this approach. The quality of these 3
macro nutrients should not be underestimated and they need to be perfectly in balance.
Fat
Protein
Carbs
Gut health is very complex. The total picture
is not even crystalized yet. But for now, to
make it more abstract, the status of gut health
is a result of the interactions between
intestines and resident bacteria in the gut.
Looking at gut level, with animal feed the
intestines (e.g. enterocytes and mucosa) are
nurtured, but also the bacteria living there; the
microbiota. Influencing the feed inevitably
results in either a positive or a negative
change in gut health. The easiest factor to
influence − and to steer gut health − is by the
animal its diet, which consists primarily of
carbohydrates, proteins and fat. Of course,
gut health is also influenced by feed additives,
vitamins and minerals, however the big 3 is
the main fraction in animal feed and therewith
the basis to regulating the animal’s gut health.
diminished performance and extensive
financial losses in their further life. With the
decrease in use of preventive antibiotics,
quality feed to optimize gut health is more
essential than ever. Covering up the
mismatches in feed (ingredients) is no longer
possible.
It is our task, as nutritionists, to keep the
animal’s gut and its microbiota healthy and
happy. If we do not supply the right balanced
feed with good quality ingredients, a
disbalance in microbiota or malnutrition in the
intestine is the result. If these disruptions take
place, a leaky gut, and ultimately diarrhea,
sickness or death, is the result (figure 1).
Animals can recover from this, however the
damage to the gut is irreversible and leads to
Figure 1: Leaky gut
Carbohydrates
Carbohydrates
can
be
divided
in
monosaccharides
(e.g.
glucose),
disaccharides (e.g. lactose) and polysaccharides. The shorter the saccharide, the
easier digestible. Mono-saccharides can
simply be absorbed into the body as they are.
And disaccharides can be digested easily,
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these just have to be ‘cut in half’ in order to be
absorbed
by
the
intestinal
wall.
Polysaccharides found in cereal grains on the
other hand, are much longer and therefore
harder to digest. The most important
polysaccharide suppling energy in a pig’s diet
is starch. Starch can be digested because the
pig produces the enzyme amylase, which is
released in the small intestine.
In early life, it is not starch but lactose being
the main energy source. In the piglet’s small
intestine, lactose (disaccharide) is broken
down by lactase, produced by the pancreas,
into
glucose
and
galactose
(monosaccharides), which can easily be
absorbed. In the graph below is shown (part
of) the enzyme activity in the young piglet’s
gastrointestinal tract. Lactase is especially
active in the first 4 weeks of life, peaking at 2
weeks. Feed for young animals should
therefore contain sufficient lactose.
Starting at 4 weeks of age amylase activity is
clearly increasing. Amylase is the enzyme
that breaks down starch in the small intestine.
At 5 weeks of age, amylase will exceed
lactase release. From this age, lactose is less
needed in the diet as an energy source,
where starch is getting more important. So,
feeding the right carbohydrates at the right
time, is key.
Source: Coffey et al., 2000, Feeding and
managing the weanling piglet, University
of Kentucky.
As already explained raw starch is a longer
chain of saccharides and therefore harder to
breakdown
and
digest.
The
right
carbohydrate source is of importance for
utilization of the energy, especially in young
animals when the digestion and amylase
production is not fully up to speed yet. To
improve
digestibility,
the carbohydrates can also be treated (Delac
Max). When starch is heated with water it
absorbs the water and slightly swells. When
temperature exceeds as certain degree,
amylose starts to dissolve and the
amylopectin starts to lose its structure and is
distorted, making the starch easier to digest
and more tasteful. Both the source and the
level of digestibility are important parameters
for influencing gut health.
Protein
The word protein was coined by the Dutch
chemist Geradus Mulder in 1838 and comes
from the Greek word protos which means of
prime importance. Protein is used by the body
to build, repair and maintain muscle tissue.
The animal’s performance – growth and
efficiency - is largely related to the protein
level of the feed and the digestibility of the
sources used. Due to the higher pH levels in
the stomach and the lower levels of enzyme
production, young animals in particular, have
trouble digesting the protein in the feed.
Undigested protein is used in the hind gut as
a substrate for microbiota and is transformed
into amines and urea. This leads to a shift in
the microbiota that is favorable to E. coli,
eventually leading to diarrhea.
Lowering protein levels in the feed is one way
to reduce the risk of protein diarrhea.
However, lower protein input also leads to
lower protein output (meat production). There
is a limit in lowering the crude protein level,
and this level depends on the raw materials
and synthetic amino acids that are available.
The second way to reduce the risk of diarrhea
is to improve the digestibility of the protein.
This can be done by adding digestibility
enhancers (enzymes) or by using raw
materials that are more digestible. Soybean
meal is the most commonly used protein
source worldwide. Young animals can have
difficulties digesting regular soybean meal.
Using more processed sources of soybean
meal and combining it with other high value
protein sources can lead to greater
digestibility and a more suitable amino acid
profile (JPC 56 / FMR Ω 3). This was shown
in a trial in which soybean meal was partly
replaced with a high quality protein source
(5% in weaner and 2.5% in starter diet).
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Fat
Fats, technically called lipids, are the most
energy dense of the three macro nutrients.
Good quality fat is better digested in the small
intestine. Fat quality can be measured by the
saturation level, the quantity of free fatty
acids, and the peroxide level. In moments of
high antimicrobial pressure in the gut, certain
pathogenic bacteria can transform bile salt
into bile acid, which reduces fat digestion.
This means that not only does fat digestion
influence gut health, but that gut health also
influences fat digestion. Feed ingredients with
emulsified high quality fats (Bigolac /
Tecnolat) can improve fat digestion when
there are not enough bile salts available for
emulsification (when animals are young).
Finally, in addition, the
equilibrium between them should also be
taken into account to avoid excesses of
building blocks or energy. They need to be
perfectly balanced in order to keep the gut –
and therewith the animal - happy.
Table 1. Partly replacement of soybean
meal with high quality protein source*
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