Hello, my name is Charmaine Espinosa, and I’m a postdoctoral research associate working
with Dr. Hans H. Stein. Today, I’ll be presenting the results of the experiment we have
conducted to determine the effect of feed sweetener and feed flavor on growth performance
of weanling pigs.

Weaning is one of the most stressful periods that results in behavioral, immunological,
and intestinal changes. At weaning, the young pig is exposed to a myriad of stressors
which cause reduction in growth performance. Such factors include removal of the piglet
from the sow- and litter-mates, transportation stress, and increased exposure to
pathogens. More often than not, weanling pigs are susceptible to infections, diseases, and
villous atrophy in the gut, which indicates that the intestinal barrier function is
disturbed after weaning. One major factor contributing in post-weaning stress is the
abrupt transition in the diet where pigs have to cope with abrupt withdrawal of sow milk,
and this often causes diarrhea due to lack of endogenous enzymes being produced by
weanling pigs.

This graph shows the voluntary metabolizable energy intake of pigs during the first 3
weeks postweaning. And what this graph clearly indicates is that the transition to eating
solid feed usually results in a critical period of underfeeding during which piglets need
to eat and adapt to digest the solid feed. Here we can observe a significant drop at
metabolizable energy intake during the weaning period and therefore are unfamiliar with
the weaning diet. As a consequence, this has both immediate and marked effects on growth,
immune response, and energy metabolism of weanling pigs.

Because of this, the continuous search for multiple and combined strategies to increase
feed consumption and growth performance after weaning is always of practical interest to
the swine industry. One of these is creep feeding. In this practice, we introduce dry
solid diets to piglets during lactation period as early as d 7 to d 18 from birth to ease
the transition from milk during the suckling period to solid feed after weaning. Creep
feed consumption is also thought to help initiate and promote gut and digestive enzyme
development that may help pigs to utilize alternative food sources once milk is removed.
Another strategy that may help improve feed intake of pigs is to supplement diets with
sensory feed additives that can change or improve the organoleptic properties of the feed
or visual characteristics of food derived from animals. Examples of these sensory feed
additives include feed flavor and feed sweetener.

The palatability of a feed is positively correlated to the taste experienced by animals.
The sense of smell is often experienced prior to consumption, and therefore, aroma is
important as an initial attractant to feed. Feed flavors are feed additives that attempt
to enhance the taste and smell of feed to stimulate feed intake. Due to its aroma, feed
flavors may also mask feed ingredients included in the diet that are unpleasant to pigs.
Previous research indicate that animals of different species and different ages prefer
different flavors; and in growing pigs, both milky vanilla and fruit flavor could
potentially enhance feed intake.

Another sensory feed additive that can be included in diets for weanling pigs to improve
feed palatability and stimulate voluntary intake is feed sweetener. Feed sweeteners are
commonly classified as non-nutritive sweeteners or high-intensity sweeteners that mimics
the effect of naturally-occurring sugar when it comes to taste, and these high-intensity
sweeteners are known to be at least 30 to 13,000 times sweeter in taste compared with
sucrose. Some examples of high-intensity sweeteners include acesulfame potassium,
advantame, aspartame, neotame, saccharin, and sucralose. Of all these high-intensity
sweeteners, saccharin was the first one to be marketed. It is about 300-500 times sweeter
than sucrose and is excreted through urine intact, providing no dietary energy. Its high
stability at high temperatures and low pH makes it an ideal sweetener to be used in pig
diets. 

With that in mind, we conducted an experiment to test the hypothesis that supplementation
of feed flavor at 500 mg/kg, as well as feed sweetener at 150 mg/kg improve growth
performance and also reduce the occurrence of diarrhea in pigs. In this experiment, feed
flavor is a milky vanilla flavor, and saccharin was the active ingredient for the feed
sweetener. 

A total of 128 weanling pigs at approximately 6 kg initial body weight was used and were
allotted to 4 diets with 8 replicate pens per treatment for a total of 32 pens in the
experiment. The 4 diets consisted of a control diet that was formulated based on corn and
soybean meal, whereas the 3 remaining diets were formulated by adding feed flavor, feed
sweetener, or the combination of feed flavor and feed sweetener to the control diet.

Experimental diets were fed for 42 d, and a 3-phase feeding program was used with d 1 to 7
as phase 1, d 8 to 21 as phase 2, and d 22 to 42 as phase 3. Individual pig weights and
daily feed allotments were recorded to be able to summarize growth performance data. Fecal
scores were assessed visually per pen every other day using a score from 1 to 5. Frequency
of diarrhea was also calculated by totaling the number of pen days with fecal scores ≥3
divided by the total number of pen days multiplied by 100.

Moving on with the results,

This graph shows the overall average daily feed intake of pigs from d 1 to d 42. FF here
represents feed flavor, whereas FS represents feed sweetener, and this setup will be the
same in the following slides. Here we can observe that supplementation of feed flavor did
not significantly improve feed intake of pigs; however, feed sweetener at 150 mg/kg in
weanling diets resulted in an increased feed intake of pigs by approximately 50 g compared
with pigs fed the control diet. 

Due to increased feed intake, we also observed a tendency for a greater average daily gain
in pigs fed diets containing feed sweetener compared with the control diet.

And the observed increase in feed intake and average daily gain subsequently resulted in a
greater final body weight in pigs fed the feed sweetener diet compared with pigs fed the
control diet. These results suggest that supplementation of feed sweetener was able to
improve voluntary energy intake and therefore growth performance of weanling pigs.

In the previous slides, we have demonstrated the beneficial effect of supplementing feed
sweetener in weanling diets. And what this slide indicates is that supplementation of feed
flavor to diets appears to reduce the incidence of diarrhea in weanling pigs. 

And based on the results of this research, we confirmed that inclusion of feed sweetener
at 150 mg/kg to diets improved growth performance of pigs, whereas feed flavor
supplementation at 500 mg/kg reduced the incidence of diarrhea in pigs. These improvements
may be a result of the positive effect of feed sweetener and feed flavor mainly on feed
intake but also may be a result of improved immune response. Therefore, further research
is needed to determine the exact and detailed mechanism of sensory feed additives in
exerting positive effects on pig performance.

We would like to take this opportunity to acknowledge DDC Nutrition and Dadhank Biotech
Corporation for their inputs and financial support.

Thank you for your interest in this presentation and if you would like to know more about
other research topics in nutrition, you can visit our website at
nutrition.ansci.illinois.edu.