Kac Para Yarismasi

Arthritis Diet and Exercises

Effect of fiber and fat on calculated values for STTD of calcium in fish meal


Hi, my name is Caroline Gonzalez-Vega, and
I’m a PhD student in Dr. Stein’s lab. And today, I have the pleasure to talk about the
effect of fiber and fat on calculated values for standardized total tract digestibility
of calcium in fish meal. This is the outline of the presentation. First,
I will start with a short introduction, and then I will explain the two experiments that
we conducted, followed by the conclusions and implications. All commercial diets contain plant ingredients.
And plant ingredients contain phytate. Therefore, when we supplement diets with calcium, some
of this calcium is bound to phytate, reducing the availability of calcium to be absorbed. But if we add phytase in the diet, the digestibility
of calcium increases, because phytase hydrolyzes the molecule of phytate, releasing phosphorus
and also reducing the chance of phytate to bind calcium. Therefore, the digestibility
of calcium and phosphorus increases if phytase is used. On the other hand, semisynthetic diets are
used in digestibility studies. But these diets do not contain phytate if cornstarch and casein
are used. Therefore, calcium-phytate complexes are not formed. So if we add phytase in this diet, phytase
may not affect the digestibility of calcium. And so far, we know that calcium from inorganic
sources may be bound to phytate, but to our knowledge there is no data about the effect
of phytate and phytase on animal calcium sources fed to pigs. Due to the relatively low calcium concentration
in plant sources, calcium needs to be supplemented in the diets. We can supplement this calcium
by using inorganic calcium sources or animal calcium sources. However, to our knowledge,
the effect of phytate and phytase on animal calcium sources has not been reported. Therefore, we decided to conduct an experiment
to evaluate the effect of phytate and phytase on the standardized total tract digestibility
of calcium in fish meal. The objective of this experiment was to test
the hypothesis that inclusion of microbial phytase increases the standardized total tract
digestibility of calcium in fish meal in diets containing phytate. We used for this experiment 40 growing pigs
with initial body weight of 19.2 kg. And we allotted them into our randomized complete
block design with five treatments. Fecal samples were collected using the marker to marker
approach. In this experiment, we used fish meal that
contained 5.7% calcium. And we included casein as the protein source because it only contains
0.03% calcium and does not contain phytate. We used corn and corn germ as our phytate
sources, and corn only contains 0.01% calcium, and corn germ contains 0.08% calcium. These are the diets that we used for this
experiment. We had two fish meal-cornstarch diets, one without phytase and the other with
500 phytase units. These diets contained fish meal, casein, and cornstarch. The other two
diets contained fish meal, corn, and corn germ, without and with phytase. For these
diets, we included fish meal, casein, corn, and corn germ. A calcium-free diet was formulated
to estimate the endogenous losses of calcium. We calculated the STTD of calcium and the
ATTD of phosphorus. And we analyzed the data using Proc Mixed of SAS as a 2×2 factorial
with 2 levels of phytate and 2 levels of phytase, and we used Orthogonal CONTRAST statements
to compare diets as well. Now, let’s move into the results. First, let’s take a moment to set up the slide.
The orange bars represent the diet with no phytase, and the blue bars represent the diets
with phytase. On the x axis, we have the standardized total tract digestibility of calcium, and
the apparent total tract digestibility of phosphorus. And underneath, we have the P
value for the effect of phytase. The y axis is expressed in percentage. So here, we have
the fish meal-cornstarch diets, and we can see that inclusion of phytase did not effect
the STTD of calcium and the ATTD of phosphorus. And this is in agreement with what we expected,
because there was no phytate in the diet. Now, looking at the fish meal-corn-corn germ
diet, we can see that if we add phytase in the diet, the digestibility of calcium and
digestibility of phosphorus increased. This is also in agreement with what we expected,
because phytase hydrolyzed phytate that was present in corn and corn germ. Therefore,
it reduced the chance of forming calcium-phytate complexes. In this slide, we show the standardized total
tract digestibility of calcium in the four diets again. Because as you can see, when
we compare the two groups of diets, the diets that contained fish meal, corn, corn germ
have greater standardized total tract digestibility of calcium than the fish meal-cornstarch diets. We know that corn and corn germ have phytate,
but it is not possible that phytate is the responsible factor for this increase. Therefore,
there may be other factors such as fiber or fat that may influence the standardized total
tract digestibility of calcium in these diets. Therefore, we decided to conduct another experiment
to determine the effect of fiber and fat on the standardized total tract digestibility
of calcium. We know that fiber increases the rate of passage.
Therefore, the nutrients have less time to be digested by the enzymes and be absorbed
in the gastrointestinal tract. But also, fiber can change the pH in the intestines. Therefore,
it enhances the solubility of some minerals, resulting in an increased digestibility. We know that fat decreases the rate of passage.
Therefore, the nutrients have more time to be digested by the enzymes and be absorbed
in the gastrointestinal tract. But also, we know that fat may form some calcium-fat complexes,
reducing the availability of calcium to be absorbed. The objective of this experiment was to test
the hypothesis that fiber or fat may influence the STTD of calcium. These are the diets that we used for this
experiment. We have a fish meal-cornstarch diet. This diet contained fish meal, casein,
and cornstarch. It was similar to the fish meal-cornstarch diet that we used in the first
experiment. The fish meal with fiber diet was similar to the previous diet, with the
exception that Solka Floc, a source of cellulose, was included at the expense of cornstarch.
The fish meal with corn diet contained the same amount of fish meal and casein, but cornstarch
was replaced by corn. The fish meal, corn, and fat diet was similar to the previous diet,
with the exception that soybean oil was included at the expense of corn. A calcium-free diet
was formulated to estimate the endogenous losses of calcium. For this experiment, we used 50 growing pigs
with initial body weight of 19.4 kg, housed individually in metabolism cages. the STTD
of calcium and the ATTD of phosphorus were calculated, and the data were analyzed using
the Proc Mixed of SAS, and Orthogonal CONTRAST statements were used to compare the diets. So, let’s move into the results. Here, the blue bars represent the fish meal-cornstarch,
and the yellow bars represent the fish meal-corn diet. Here, we compared the cornstarch diet
and the corn diet. And as you can see, the standardized total tract digestibility of
calcium and the apparent total tract digestibility of phosphorus is reduced if a cornstarch diet
is used compared with a corn diet. One possible explanation for this observation is that soluble
fiber from corn gets fermented, and the production of short chain fatty acids lowers the pH,
enhancing the solubility of the minerals, which increases the digestibility of calcium
and phosphorus. Here, the blue bars represent the fish meal-cornstarch
diet, and the green bars represent the fish meal-cornstarch with fiber diet. Here, we
observe that the fish meal-cornstarch diet reduced the STTD of calcium and the ATTD of
phosphorus compared with the fish meal-cornstarch with fiber diet. Remember that the source
of fiber here is pure cellulose, which is not fermentable. Therefore, here, there is
no production of short chain fatty acids, which may indicate that maybe there is another
factor that may be responsible for the effect on the STTD of calcium and the ATTD of phosphorus.
Another possible explanation is that in the fish meal-cornstarch diet, precipitation of
minerals occurs. Therefore, additional fiber may avoid some precipitation, which results
in an increased digestibility of calcium and phosphorus. Here, the yellow bars represent the fish meal-corn
diet, and the orange bars represent the fish meal-corn with fat diet. Here, we observe
no difference in the standardized total tract digestibility of calcium and the apparent
total tract digestibility of phosphorus between the fish meal-corn diet and the fish meal-corn
with fat diet. Therefore, fat did not have any effect on the STTD of calcium and the
ATTD of phosphorus. Here, we show the STTD of calcium in the four
diets again. So as you can see, the fish meal-cornstarch diet had the least STTD of calcium. Fiber
increased the STTD of calcium, but not as much as the fish meal-corn diet, which is
almost double than the fish meal-cornstarch. Therefore, there are some factors such as
production of short chain fatty acids or avoiding precipitation of the minerals or other factors
that we are not aware that are responsible for these differences. In conclusion, phytase increased the STTD
of calcium and the ATTD of phosphorus in diets containing phytate. Semisynthetic diets, or
cornstarch diets, reduced the STTD of calcium and the ATTD of phosphorus in fish meal. Fiber increased the STTD of calcium. This
may be by production of short chain fatty acids, or avoiding precipitation of minerals.
Fat did not affect the STTD of calcium. Results from these two experiments indicate
that values for STTD of calcium from corn diets may be more representative of commercial
diets. With this, I want to thank you for your attention.
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