Slide 1
Hello. This is Yanhong Liu. I'm working with Dr. Stein as a post-doc. Today,
we're going to talk about one experiment with the title “Retention and
digestibility of zinc, copper, manganese, and iron in pigs fed diets containing
inorganic or organic micro minerals."

Slide 2
First, I will start a brief introduction of some micro minerals, and then we
will go to the objective of this experiment, and showing the materials and
methods, and then we will move to the results and discussion, and finally I will
give some conclusions about this experiment.

Slide 3 
Micro minerals such as zinc, copper, and manganese are very important for
growth, reproduction, and the immune system because they are the required
co-factor for several hundred enzymes and they are involved in the structure of
various transcription  factors and other proteins. 
Therefore, providing enough amounts of micro minerals to animals is crucial for
their growth and health. But the supplementation of micro minerals often exceed
the requirements, which results in relatively high levels of micro minerals
excretion from animals.  Two main categories of micro minerals: inorganic and
organic micro minerals. Inorganic micro minerals are normally inorganic salts,
such as mineral sulfate, oxide, and others. Organic micro minerals are the
minerals binding to the organic ligands.  

Slide 4
Many factors affect the digestibility and absorption of micro minerals, such as
the low pH in the stomach and duodenum, which may induce dissociation of micro
mineral salts, and results in the loss of micro minerals to the antagonists. The
phytic acid in the diets can form a stable and highly insoluble complex with
inorganic salts, and reduce the mineral absorption. Antagonism among minerals,
such as the high levels of molybdenum and selenium, can interfere with copper
absorption. And the last one is the high fiber diets. The high fiber diet may
increase the endogenous losses, and then decrease the digestibility of micro
minerals. A potential advantage of organic micro minerals is that the binding of
organic ligands to the mineral should provide stability of the complex in the
upper GI tract, minimizing the mineral losses to the antagonists, and allow the
complex to be delivered to the absorptive epithelium of the small intestine for
mineral uptake. Use of organic micro minerals instead of inorganic micro
minerals may reduce the excretion of minerals from animals.

Slide 5
Therefore, the objective of this experiment was to determine the apparent total
tract digestibility and the retention rate of zinc, copper, manganese, and iron
in pigs fed either inorganic or organic micro minerals.

Slide 6
A total of 32 barrows with initial body weight 38 kg were used in this
experiment. They were randomly allotted to 4 dietary treatments with 2 by 2
factorial arrangement. So there were 8 replicates per treatment. The first two
factors were two different diets, semi-synthetic diets and the corn-soybean meal
diets. The second factor were two different sources of micro minerals, inorganic
micro minerals versus organic micro minerals. 

Slide 7
This table is showing two different diets: semi-synthetic diets and corn-soybean
meal diets. From here we can see, the semi-synthetic diets contained 64% corn
grits, 10% soy protein, and 20% sorghum, but the corn-soybean meal diet
contained 75% corn and 22% soybean meal. So compared with semi-synthetic diet,
corn-soybean meal diet contained relatively higher crude fiber and phytic acid.

Slide 8
The inorganic micro minerals were sulfate salts for zinc, copper, manganese, and
iron. The organic sources of zinc, copper, and manganese were the chelate of one
mineral and two 2-hydroxy-4-methylthio botanic acid, and the organic source of
iron was a chelate of one iron and one glycine. This figure in the right corner
showed one example of organic zinc. 

Slide 9
Before starting the experiment, there were two weeks depletion period. All pigs
in this period were housed in individual pens and fed the semi-synthetic diet
without supplementation of any of these four micro minerals. After that, all
pigs were transferred to metabolism cages and housed there for 14 days. Pigs
were fed the experimental diets for 5 days as adaptation, and the urine and
fecal samples were collected 5 to 7 days based on marker to marker approach. 

Slide 10
The apparent total tract digestibility and the retention rate of micro minerals
were calculated. All data were analyzed by Proc Mixed of SAS with a randomized
complete block design. Model included type of diets, source of minerals, and
their interaction as a fixed effect and the groups as a random effect. The P
value less than 0.05 were considered as significant. 

Slide 11
Now, let’s move to the results. So, for all the figures in the results, the X
axis represents two different diets, semi-synthetic diets and the corn-soybean
meal diets. And the yellow bar represents inorganic micro minerals, and the red
bar represents organic micro minerals. On the Y axis was the ATTD or the
retention rate of the micro minerals. So the first figure here, we can see the
apparent total tract digestibility of zinc. Compared with the semi-synthetic
diet, corn-soybean meal diet had the relatively lower ATTD of zinc. So this
result indicates that the phytic acid or the relatively high fiber concentration
in the corn-soybean meal diet may have a negative effect on the ATTD of zinc.
Compared with the inorganic micro minerals, organic micro minerals had a greater
ATTD of zinc. So this result indicates supplementation of organic micro minerals
may increase the digestibility of these micro minerals. No interactions were
observed. 

Slide 12
This figure is showing the retention rate of zinc. From here we can see there is
no diet effect for the retention rate of zinc. Compared with inorganic micro
minerals,  organic zinc increase the retention rate of zinc. There was no
interaction between type of diets and source of minerals.

Slide 13
This figure is showing the apparent total tract digestibility of copper. So,
from here we can see no diet effect. But compared with inorganic micro minerals,
pigs fed organic micro minerals had the relatively higher ATTD of copper. And
there were significant interaction between type of diets and source of micro
minerals. So here we can see, in the semi-synthetic diet, no difference between
inorganic and organic micro minerals, but in the corn-soybean meal diets,
compared with the inorganic micro minerals, organic micro minerals increased the
ATTD of copper. So these results indicate the low pH in the upper GI tract may
have a relatively lower effect on the ATTD of copper, but the phytic acid in the
corn-soybean meal diet may have a negative effect on the digestibility of
copper.

Slide 14
This figure shows the retention rate of copper. Similar as the apparent total
tract digestibility of copper, no diet effect. Compared with inorganic micro
minerals, organic micro minerals increased the retention rate of copper. And
there is significant interaction between type of diets and source of minerals,
similar as the ATTD of copper: in semi-synthetic diets, no difference between
the inorganic and organic micro minerals, but in corn-soybean meal diet,
compared with inorganic micro minerals, organic micro minerals increase the
retention rate of copper.

Slide 15
This figure shows the apparent total tract digestibility of manganese. No diet
effect, similar as the copper. And compared with inorganic micro minerals,
organic micro minerals increased the ATTD of manganese. There was a tendency of
an interaction between the type of diets and the source of minerals, similar as
the copper: in the semi-synthetic diet, no difference between inorganic and
organic micro minerals, but in the corn-soybean meal diet, compared with the
inorganic micro minerals, organic micro minerals increased the ATTD of
manganese.

Slide 16
This figure is showing the retention rate of manganese. Similar as the ATTD of
manganese, no diet effect, but compared with the inorganic micro minerals, pigs
fed the organic micro minerals had the greater retention of the manganese. And
there was significant interaction between the diets and source of micro
minerals. In semi-synthetic diet, there was no difference between inorganic and
organic micro minerals, but in corn-soybean meal diet, compared with inorganic
micro minerals, organic micro minerals increased the retention of manganese.

Slide 17
This figure is showing the ATTD of iron. There is no diet effect, but compared
with inorganic micro minerals, organic micro minerals increased the ATTD of
iron. And there was significant interaction between the diets and source of
minerals. In semi-synthetic diets, no difference between inorganic and organic
micro minerals; but in corn-soybean meal diet, compared with the inorganic micro
minerals, organic micro minerals increased the ATTD of iron.

Slide 18
This figure is showing the retention rate of iron. No diet effect, similar as
the ATTD of iron. Compared with the inorganic micro minerals, organic micro
minerals increased the retention rate of iron. There are significant interaction
between type of diet and source of minerals. In semi-synthetic diets, no
difference between inorganic and organic micro minerals, but in corn-soybean
meal diets, organic micro minerals had a greater retention rate of iron than
inorganic micro minerals.

Slide 19
The last figure shows the ATTD of phosphorus. From this figure we can see,
compared with semi-synthetic diet, corn-soybean meal diet had lower ATTD of
phosphorus. This is reasonable because the phytic acid in the corn-soybean meal
diet may have a negative effect on the digestibility of phosphorus. Compared
with inorganic micro minerals, organic micro minerals increased the
digestibility of phosphorus. So this result indicates supplementation of organic
micro minerals also increased the digestibility of phosphorus. But there was no
interaction observed here.

Slide 20
So based on these results, we conclude: organic forms of micro minerals have
improved digestibility and retention rates compared with the inorganic forms.
Supplementation of organic micro minerals also increased the digestibility of
phosphorus. Inclusion of organic micro minerals in high-phytate diets may be
more beneficial than in low-phytate diets.

Slide 21
With that, we'd like to thank Novus for the financial support. And also, thanks
for listening to this podcast. If you want know more information about our
research, please go to the website: nutrition.ansci.illinois.edu.