Chemistry Reference
In-Depth Information
All canned diets must undergo retort. Both processes kill the majority of bacteria in
the food, including probiotic strains. Additionally, most pet foods are guaranteed to
have a shelf life of up to 1 year. Probiotics may not survive for this length of time,
thus no label guarantee can be made.
Weese and Arroyo
33
evaluated 19 commercial pet foods claiming to contain pro-
biotics. Of those 19 pet foods, 13 were for dogs and 6 were for cats. All diets were
evaluated prior to their indicated expiration date. None of the tested diets contained
all organisms listed on the ingredient label. Of the 19, 10 (53 percent) diets had at
least one microorganism listed on the ingredient label; 5 (26 percent) products had
no probiotic bacteria present. Some diets allegedly contained bacterial fermentation
products without the bacteria itself listed as an ingredient, but still claimed to con-
tain a probiotic.
33
The need for proper ingredient labeling, oversight of claims, and
guidelines for probiotics in pet foods is obvious.
Although there are some difficulties still to overcome, probiotics have been
noted to have positive effects both
in vitro
and
in vivo. In vitro
research has, to date,
evaluated only various strains of lactobacilli. The first study measured the effects
of a probiotic cocktail (three
Lactobacillus
spp.) on mRNA inflammatory cytokine
expression in intestinal samples from dogs suffering from chronic enteropathies
compared with healthy dogs.
14
The ratio of regulatory to inflammatory cytokines
was improved following the addition of probiotics, suggesting that this may be of
use
in vivo
to decrease inflammation in the intestinal tissue.
14
A second study iso-
lated and evaluated
L. murinus
as a potential probiotic in dogs.
16
After isolation, the
probiotic was tested to determine its ability to survive in different pH and bile salt
conditions, to inhibit growth
in vitro
of
E. coli
and
C. perfringens
, and to adhere to
glass and intestinal mucus. All criteria were met with
L. murinus
and, therefore, it
may be capable of surviving the gastrointestinal tract of the dog and lead to benefi-
cial effects in the host.
16
Results
in vivo
appear to be positive, but some conflicting results occur. Due to
the varying doses and mode of administration, it is difficult to quantify trends occur-
ring due to probiotic supplementation. Overall trends suggest that probiotic bacteria,
administered at a sufficiently high dose, will lead to increases in gut probiotic bacte-
rial species, as well as a decrease in potentially pathogenic bacteria. During feeding
of a probiotic, most studies (79 percent) indicated the presence of, or a significant
increase in, the probiotic species in fecal matter. Four studies indicated a decrease
in fecal
C. perfringens
or
Escherichia coli,
which often are considered potentially
pathogenic bacteria when allowed to grow above normal levels. One problem with
probiotic supplementation is that bacteria disappear shortly after cessation of supple-
mentation. Therefore, these changes are not lasting, indicating that probiotic bacteria
are likely not attaching and colonizing within the gastrointestinal tract. Biourge et
al.
32
indicated no detection of probiotic species (
Bacillus
CIP 5832) after 3 days of
probiotic cessation, and Weese and Anderson
23
noted
L. rhamnosus
probiotic pres-
ent in only one dog after 72 hours of removal. This was contrary to Marciňáková et
al.
20
who found survival of
Enterococcus faecium
EE3 after a 3-month cessation of
probiotic treatment. The authors indicated that
E. faecium
EE3 is a strain that has
