Nutrition and Disease
The Use of Probiotics in the Diet of Dogs1
Vincent Biourge,2 Ce ´ line Vallet, Anne Levesque, Renaud Sergheraert, Ste ´ phane Chevalier*
and Jean-Luc Roberton*
Research & Development, Royal Canin and *Prodeta, Vannes, France
EXPANDED ABSTRACT
KEY WORDS: ● Bacillus CIP 5832 ● dogs● dry food
Probiotics are microorganisms such as bacteria or yeast that
can be added to the food with the purpose of regulating the
intestinal flora of the host (Parker 1974). Probiotics have been
used therapeutically in the treatment of diarrhea or prophy-
lactically in humans and animals to minimize drift in the
composition of the intestinal microflora associated with anti-
biotherapy or traveler’s gastroenteritis (Barrows and Deam
1985, Lestradet 1995, Van De Kerkove 1979).
More recently, probiotics have also been found to have
beneficial effects on the health of the host (Fuller 1989). The
mechanisms are not completely understood, but they could be
due to the ability of probiotics to act as regulators of the
intestinal microflora as a source of digestive enzymes and/or
stimulating factors on the immune system (Lestradet 1994).
This is the rationale behind the use of probiotics in the feed of
farm animals, i.e., to improve their breeding performance
despite all of the stresses (high animal concentration, early
weaning or rapid growth) associated with modern husbandry
(Lestradet 1994).
Weaning, a new home and dietary changes are all condi-
tions that are known to affect the intestinal microflora of dogs
and for which probiotics might be beneficial. Probiotics might
also be of benefit to dogs living in a large colony or sold in pet
shops in which animal concentration, pressure of infection
and stress can significantly affect animal resistance to disease.
Paciflor is a patented strain of Bacillus recorded at the
Pasteur Institute under the number CIP 5832 and marketed as
a feed additive in animal nutrition (Lestradet 1995). The
bacillus is commercialized in its sporulated form, allowing a
better resistance to heat and better stability over time. Bacillus
CIP 5832 has been shown to have beneficial effects on the
survival of mice infected with Klebsiella pneumoniae and on the
breeding performances of rabbits, pigs, chickens, turkeys,
ducks, calves and horses (Lestradet 1995). Bacillus CIP 5832 is
also the active ingredient in Bactisubtil (Merrell, Neuilly-sur-
Seine, France) a drug approved in France in the 1950s and
1 Presented as part of the Waltham International Symposium on Pet Nutrition
and Health in the 21st Century, Orlando, FL, May 26–29, 1997. Guest editors for
the symposium publication were Ivan Burger, Waltham Centre for Pet Nutrition,
Leicestershire, UK and D’Ann Finley, University of California, Davis.
2 To whom correspondence should be addressed.
recommended in infants against antibiotic-induced diarrhea
(Lestradet 1995).
A series of pilot studies were undertaken to evaluate the
feasibility of including a probiotic in dry dog foods, to deter-
mine the kinetics of Bacillus CIP 5832 in vivo in dogs and to
assess its effects on diet digestibility.
Materials and methods. Bacillus CIP 5832 is commer-
cially available in its sporulated form as a powder (Paciflor,
Prodeta, Vannes, France) at the concentration of 1010 colony
forming units (CFU)/g. The recommended dosage in the food
is 106 CFU/g.
A first set of experiments was planned to assess the feasi-
bility of including Bacillus CIP 5832 in a dry dog food. In the
first experiment, the probiotic was added to the meal of a
commercial diet [RCCI M25 (protein 250 g/kg, fat 120 g/kg,
minerals 70 g/kg and dietary fibers 65 g/kg), Royal Canin,
Aimargues, France] before expansion-extrusion at a dose of
106 CFU/g of meal. Spore survival was evaluated in the meal
and the expanded diet. In a second experiment, survival was
evaluated with the probiotic added to a powder (500 g/kg
brewers yeast-500 g/kg lactalbumen) to obtain a final concen-
tration 108 CFU/g of powder. This powder was then coated
(10 g/kg of diet) on four batches of a pilot diet (protein 320
g/kg, fat 240 g/kg, minerals 69 g/kg and dietary fiber 55 g/kg)
after expansion-extrusion and drying. Samples of these four
batches were then followed over 1 y to evaluate Bacillus
survival over time. Bacillus CIP 5832 concentration on five
samples of each diet was determined in 10 g of ground diet as
described in Michard and Levesque (1989). For the survival
study, samples of the batches were kept in commercial pack-
aging at room temperature in a dry, well-ventilated warehouse.
Spore survival was evaluated after 0, 6, 9 and 12 mo.
In the second set of experiments, the kinetics of Bacillus
CIP 5832 in dogs was evaluated. Five female spayed dogs (2
German Pointers and 3 German Shepherds, age 5–10 y, weight
24 3 kg) belonging to the dog colony of the Royal Canin
Research Center were used. The colony is approved and reg-
ularly inspected by veterinarians of the French “Direction des
Services Ve ´te ´rinaires.”
For all of the studies, Bacillus CIP 5832 was mixed at a
concentration of 1.5 108 CFU/g to a powder made by
grinding the same commercial diet as the one used for feeding
0022-3166/98 $3.00 © 1998 American Society for Nutritional Sciences. J. Nutr. 128: 2730S–2732S, 1998.
2730SExpected
concentration
in the batch1
Concentration found in the diet in 106 colony forming units/ g of diet2 after
0 mo 6 mo 9 mo 12 mo
Batch 1 1.3 1.1 0.3 0.9 0.1 0.9 0.2 0.7 0.4
Batch 2 1.6 0.8 0.1 0.6 0.2 0.6 0.1 0.6 0.1
Batch 3 1.2 0.8 0.1 0.7 0.3 0.5 0.1 0.6 0.1
Batch 4 1.5 0.7 0.1 0.6 0.1 0.6 0.2 0.6 0.2
Mean loss (%) 46* 17** 23** 25**
PROBIOTICS IN THE DIET OF DOGS 2731S
TABLE 1
Effects of Process and Time on the Survival of Bacillus CIP 5832 Added to Four Batches of
Commercial Dry Dog Food as a Powder Coating
1 Calculated from Bacillus CIP 5832 concentration in the coating powder
2 Results are the mean SEM for 5 samples.
*
,** Compared with expected concentration and mo 0, respectively.
the dogs (RCCI M25, Royal Canin, Aimargues, France). Ba-
cillus concentrations in the mix were checked before, during
and after the study as described above. To evaluate the delay
of appearance and disappearance of Bacillus CIP 5832 in the
feces, 5 g of the mix was added or no longer added to the daily
meal (493 28 g of kibbles/d, thus 1.5 106 CFU/g diet).
All feces were collected 1 d before and 7 d after Bacillus CIP
5832 supplementation or removal. Fecal samples were individ-
ually frozen ( 18°C) pending analysis, and Bacillus concen-
tration was determined before (spores vegetative forms) and
after heat treatment (80°C for 10 min, spores only) as de-
scribed in Michard and Levesque (1989). Before the disap-
pearance study, dogs had been supplemented for 3 wk with the
Bacillus CIP 5832. For the Bacillus CIP 5832 balance study, the
diet of the dogs was supplemented with 5 g of the probiotic
mix as described above, all feces were collected and pooled for
each dogs over a 5-d period and frozen pending analysis. Dogs
had been supplemented with Bacillus CIP 5832 for 2 wk before
the study.
Dry matter, protein, lipid and energy digestibility studies
were conducted according to the American Association of
Feed Control Officials (AAFCO 1997) protocol without or
with the daily addition of 7.5 108 CFU of Bacillus CIP 5832.
All results are expressed as the mean standard error
(SEM). Digestibility results were compared using a paired Stu-
dent’s t test; P 0.05 was considered to be significant.
Results and discussion. The first set of experiments was
intended to prove that Bacillus CIP5832 could be added to a
dry dog food and to evaluate the loss of viable spores over a
12-mo shelf life.
Resistance of Bacillus CIP 5832 to expansion-extrusion and
drying. Bacillus CIP 5832 concentration in the meal and in
the expanded product was 1.10 0.04 106 and 0.02
0.05 106 CFU/g, respectively. The extrusion-expansion and
drying process resulted thus in the loss of 99 % of the spores.
Bacillus CIP 5832 should thus not be included in the diet
before the extrusion- expansion and drying process.
Resistance of Bacillus CIP 5832 when applied as a powder
coating. After powder coating, the observed level of spores
was 60% of the expected levels in four different batches
(Table 1). These relatively high losses may be due in part to
spores trapped within the lipid fraction of the diet when the
ground food is mixed in 0.2% sodium hydroxide as the first
step of the bacteriological count. However, despite these ap-
parent losses, powder coating remains an efficient and conve-
nient way to add Bacillus CIP 5832 to the diet.
Spore survival over time. Follow-up of four different batches
over a 12-mo period was associated with a loss of spores of
25% compared with the bacteriological count just after
processing (Table 1). These three pilot studies confirmed that
addition of Bacillus CIP 5832 to a dry dog food is feasible.
FIGURE 1 Total Bacillus CIP 5832 count in the fresh feces of five
dogs after dietary supplementation [d 0, 7.5 x 108 CFU/(dog d)].
Results are expressed as a mean SEM.
FIGURE 2 Total Bacillus CIP 5832 count in the feces of five dogs
after stopping dietary supplementation (d 0). Results are expressed as
a mean SEM.2732S
SUPPLEMENT
Bacillus CIP 5832
Digestibility in %1
Dry matter 86.4 0.4 86.9 0.3
Protein 83.4 0.8 84.2 0.6
Lipids 95.9 0.2 95.6 0.3
Energy 83.9 0.3 84.1 0.2
TABLE 2
Dry Matter, Protein, Lipid and Energy Digestibilities
in Five Dogs Supplemented or Not with 7.5 106 CFU
of Bacillus CIP 5832
1 Results are expressed as meansdifference due to Bacillus CIP 5832.
SEM. There was no significant
Bacillus CIP 5832 balance. The balance study showed that
29.6 5.6% of the Bacillus CIP 5832 ingested was found in
the feces of the five dogs; 69.9 3.5% was in vegetative form.
As expected from studies in other species, Bacillus CIP 5832
will thus survive and germinate in the gastrointestinal tract of
dogs but will not persist if not fed continuously (Lestradet
1995).
Effect of Bacillus CIP 5832 on dry matter, protein, lipid and
metabolizable energy digestibility. Although the digestibilities
appeared slightly improved with the probiotic, the difference
were not significant (Table 2).
In summary, these studies demonstrated that the addition of
Bacillus CIP 5832 to a dry dog food was feasible under certain
circumstances and that Bacillus CIP 5832 will survive and
germinate in the gastrointestinal tract of dogs.
The second set of experiments was intended to prove that
Bacillus CIP 5832 could survive in the gastrointestinal tract of
dogs as well as to determine the time required for its appear-
ance and disappearance in the feces. Dogs consumed all of
their food as well as the mix containing the spores in all
studies.
Delay of appearance of Bacillus CIP 5832 in the feces. When
the probiotic was added to the diet, spores and vegetative
forms were detected in the feces within 24 h and reached a
plateau within 2 and 4 d, respectively (Fig. 1).
Delay of disappearance of Bacillus CIP 5832 from the feces.
When the probiotic was withdrawn from the diet, spores and
vegetative forms could not longer be detected after 3 d
(Fig. 2).
LITERATURE CITED
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