Hi, this is Yanhong Liu. Today, I will talk about an experiment to determine the
effects of a novel phytase on growth performance and metacarpal bone ash in
weanling pigs.

First, I will briefly introduce the phytate and phytase, and also show the
objective of this experiment. And then I will show the detail about how we
conducted this experiment. And then move to the results, and finally I will give
an overall conclusion.

Why phosphorus is important: Phosphorus is a key structural mineral in bones and
teeth, and phosphorus is a component of DNA and RNA. Phosphorus is critical in
the structural integrity of all cellular membranes, and it also is very critical
in metabolic energy systems. Therefore, a consistent supply of phosphorus is
required to support pig production.

There are two types of feed ingredients to supply phosphorus in animal feed. The
animal origin feed ingredients do not contain any phytate, but a high percentage
of phosphorus is bound to phytate in plant origin feed ingredients. Inorganic
phosphorus sources are also available in feed market. And these inorganic
sources do not contain any phytate. There are two common phosphorus sources used
in pig diets, which include monocalcium phosphate and dicalcium phosphate.

So what is phytate? The full name of phytate is myo-inositol hexakisphosphate.
Phytate has antinutritional effects because phytate can form a complex with
calcium, phosphorus, protein, and trace minerals. Because of this complex,
phytate can reduce digestibility of these nutrients. So therefore, they can
increase the environmental pollution, such as they can increase the nitrogen
excretion and phosphorus excretion. Because of reduced digestibility of
nutrients by phytate, there are decreased profitabilities.

Phytase is an enzyme to catalyze the hydrolysis of phytate to inositol and
inorganic phosphorus. And after the hydrolysis, this inorganic phosphorus can be
utilized by animals.

There are two different types of phytase in the market. The fungal phytase is
from Aspergillus or Peniophera species, and the bacterial phytase is normally
from E. coli. So adding phytase in an animal diet can reduce inclusion of
inorganic phosphorus and calcium sources in animal feeds, because they can
increase the digestibility of calcium and phosphorus. Adding phytase to animal
diets also has beneficial effects on the environment, because they can reduce
the phosphorus and nitrogen excretion.

The objective of this experiment was to determine the effects of a novel
next-generation phytase on growth performance and metacarpal bone ash of
weanling pigs. The brand name of this phytase is Cibenza Phytaverse G10.

A total of 160 pigs with 35 days of age and initial body weight of around 9.79
kg were used in this experiment. The experiment was conducted with two phases
and two weeks for each phase. There were four diets in each phase, based on corn
and soybean meal. The first diet was the positive control diet, with the
digestible phosphorus met the requirement. The second diet was negative control
diet, with 56 to 58% digestible phosphorus compared with positive control diet.
The third and fourth diet was negative control plus 250 or 500 FTU/kg Cibenza
Phytaverse G10. There were ten replicate pens per treatment, and two barrows and
two gilts per pen.

This table shows the negative control and positive control diet in phase 1. From
this table we can see both negative control diet and positive control diet
contained similar amounts of corn and soybean meal. The only difference between
negative control and positive control diets was, the negative control diet
contained 0.23% monocalcium phosphate, but the positive control diet contained
1.03% monocalcium phosphate.

This slide shows the nutritional composition for these two diets. From this
table, we can see negative control diet and positive control diet contained
similar amount of dry matter and crude protein, but they have different amount
of ash, calcium, and phosphorus. So negative control diet contained 4.07% ash,
0.75% calcium, and 0.41% phosphorus. But the positive control diet contained
4.49% ash, 0.82% calcium, and 0.56% phosphorus.

The growth performance was checked by calculating the average daily gain,
average daily feed intake, and gain:feed ratio. At the end of the experiment two
pigs per pen, one barrow and one gilt, were euthanized to collect third and
fourth metacarpal bones from the right foot. The bone ash and phosphorus were
measured in these bones.

All data were analyzed by Proc GLM with completely randomized design. The
statistical model included diet as fixed effect and pen as experimental unit.
The orthogonal contrasts were conducted to test linear and quadratic effects of
graded level of phytase.

Move to the results...

The first figures show the overall average daily gain. So, first let me set up
the slide. The y axis, we have the average daily gain. And the x axis, we have
the four dietary treatments. The green bar represents the positive control diet,
and light blue represents negative control diet, and light yellow represents 250
FTU/kg phytase, and the orange bar represents 500 FTU/kg phytase. So from this
figure we can see, compared with the positive control diet, pigs fed negative
control diet had the lower overall average daily gain.

And adding phytase to negative control diet linearly increased overall average
daily gain.

For the overall average daily feed intake, again compared with the positive
control, pigs fed negative control diet had lower average daily feed intake, and
adding phytase linearly increased the average daily feed intake.

Overall gain:feed ratio, compared with the positive control diet, negative
control diet reduced the gain:feed ratio. Adding phytase to negative control
diet linearly increased the gain:feed ratio of weanling pigs.

This slide shows the bone weight. This is the fat free bone weight, so again
compared with the positive control diet, pigs fed negative control diet had a
lower fat free bone weight. And adding phytase to negative control diet linearly
increased the fat free bone weight.

And this slide shows the bone ash weight. Again, compared with positive control
diet, pigs fed negative control diet had lower bone ash weight, and adding
phytase linearly increased the bone ash weight.

For the bone phosphorus weight, compared with the positive control diet, pigs
fed negative control diet reduced the bone phosphorus weight. And adding phytase
to negative control diet linearly increased the bone phosphorus weight.

We calculated the bone ash percentage from bone ash weight divided by the fat
free bone weight. So this figure shows the percentage. Compared with the
positive control, pigs fed negative control diet had lower bone ash percentage,
and adding phytase linearly increased the bone ash percentage.

For bone phosphorus percentage, again compared with the positive control diet,
pigs fed the negative control diet reduced the bone phosphorus percentage, but
adding phytase did not affect bone phosphorus percentage.

Based on the results shown above, the overall conclusion for this experiment
was: this novel phytase supplementation to a phosphorus-deficient diet based on
corn and soybean meal improved phosphorus utilization by weanling pigs.

Thank you so much for listening to this presentation. If you have any questions
related to this experiment, please go to our website. You can find the research
summary there, and also you can contact Dr. Stein for more information.