Objective—To determine relationships between fecal
consistency and colonic microstructure and absorptive
function in dogs with and without nonspecific
Animals—12 dogs with nonspecific dietary sensitivity
(affected) and 9 healthy dogs (controls).
Procedure—Affected dogs were fed 4 test diets and
control dogs, 3 diets for 4 weeks each in a crossover
design. Fecal consistency was assessed daily. At the
end of each feeding period, electrolyte and water
transport were assessed, and colonic biopsy specimens
were obtained for histologic examination and
measurement of crypt water uptake by use of confocal
Results—Feces were consistently looser in affected
dogs. In control dogs, we detected net colonic
absorption of sodium and chloride and secretion of
potassium and bicarbonate. Absorption of sodium
and chloride was less in affected dogs, compared
with controls, indicating that electrolyte transport was
disrupted in affected dogs. This disruption was accentuated
during feeding of diets associated with significantly
poorer fecal consistency (ie, loose feces). Fecal
consistency was inversely correlated with crypt water
absorption, which was reduced in affected dogs.
Colonic crypts were shorter and less dense in affected
dogs fed diets associated with poor fecal consistency,
compared with affected dogs fed other diets or
with control dogs.
Conclusions and Clinical Relevance—Colonic transport
function is a major determinant of fecal consistency
in dogs. Dogs with nonspecific dietary sensitivity
are particularly susceptible to diet-induced
changes in absorptive function. Such changes are
associated with damage to colonic microstructure,
disrupted electrolyte transport, and failure to dehydrate
luminal contents. (Am J Vet Res 2002;
Objective—To determine effects of age and sex on
plasma lipid and lipoprotein metabolism in cats.
Animals—33 kittens and 16 adolescent, 23 adult, and
10 senior cats.
Procedure—Plasma concentrations of cholesterol,
triglyceride, and lipoprotein-cholesterol and activities
of lipoprotein lipase, hepatic lipase, and lecithin:cholesterol
acyl transferase (LCAT) were measured and
compared within and among groups.
Results—Plasma cholesterol and triglyceride concentrations
were significantly higher in 5- and 7-week-old
kittens, compared with the same kittens after weaning
and cats in the other age groups. Cholesterol concentration
was significantly less in 20-week-old kittens,
compared with adolescent and adult cats. Lipid
and lipoprotein-cholesterol concentrations were not
significantly different among the adolescent, adult,
and senior groups, nor did sex influence lipid and
lipoprotein-cholesterol concentrations in these
groups. Activities of lipoprotein and hepatic lipases
were significantly less in senior cats, compared with
the other groups. Activity of LCAT was highest in 20-week-old kittens and was greater in sexually intact
adult and adolescent females, compared with their
male counterparts. After castration, activities of
hepatic lipase and LCAT significantly decreased in
adolescent male cats.
Conclusions and Clinical Relevance—The upper
limits of reference ranges for plasma cholesterol and
triglyceride concentrations should be increased for
kittens < 8 weeks of age. Low cholesterol concentrations
in adolescent cats likely reflect high tissue
demands for growth and steroidogenesis. Decrease
in lipoprotein and hepatic lipase activity in senior cats
could predispose this age group to hypertriglyceridemia,
particularly in insulin-resistant cats or those
fed a high fat diet. (Am J Vet Res 2001;62:331–336)
Objective—To evaluate viability of a probiotic strain of
Lactobacillus acidophilusin a dry dog food, determine
its ability to survive transit through the gastrointestinal
tract and populate the colon, and assess its
effects on intestinal and systemic parameters.
Animals—15 adult dogs.
Procedure—Dogs were sequentially fed a dry control
food for 2 weeks, the same food supplemented with
> 109L acidophilus for 4 weeks, and the control food
again for 2 weeks. Fecal score was assessed daily,
and fecal and blood samples were collected for enumeration
of bacterial populations and measurement
of hematologic variables.
Results—Recovery of L acidophilus from the supplemented
food was 71% and 63% at the start and end
of the study, respectively, indicating that the bacteria
were able to survive manufacture and storage. The probiotic
bacterium was detected in feces via ribotyping
and RNA gene sequencing during the probiotic administration
phase but not 2 weeks after cessation of
administration. Administration of the probiotic-supplemented
food was associated with increased numbers
of fecal lactobacilli and decreased numbers of clostridial
organisms. There were significant increases in
RBCs, Hct, hemoglobin concentration, neutrophils,
monocytes, and serum immunoglobin G concentration
and reductions in RBC fragility and serum NO
Conclusions and Clinical Relevance—These data
indicate that L acidophilus can be successfully incorporated
into a dry dog food, survive transit through the
canine gastrointestinal tract, and populate the colon
and are associated with local and systemic changes.
This probiotic bacterium may have the potential to
enhance intestinal health and improve immune function
in dogs. ( Am J Vet Res 2004;65:338–343)
Objective—To determine the effects of increases in dietary intake of polyunsaturated and saturated fatty acids on plasma lipid and lipoprotein concentrations and activity of associated enzymes in healthy domestic cats.
Procedures—A baseline diet (40% energy from fat) and 4 test diets, with increased amounts of fat (51% and 66% energy from fat) from the addition of polyunsaturated and saturated fatty acids, were fed for 6 weeks each. Plasma cholesterol, triglyceride, and lipoprotein cholesterol concentrations, along with activities of lipoprotein lipase, hepatic lipase, and lecithin-cholesterol acyl transferase, were measured at the end of each feeding period.
Results—Diet, amount of fat, or ratio of polyunsaturated to saturated fatty acids had no effect on plasma concentrations of cholesterol, triglycerides, and very–low-density or high-density lipoproteins or the activity of lecithin-cholesterol acyl transferase. Low-density lipoprotein concentrations were significantly lower in cats fed a high-fat diet containing polyunsaturated fatty acids. Lipoprotein concentration and hepatic lipase activity were significantly higher in cats fed the fat-supplemented diets, and this was unrelated to whether diets were enriched with polyunsaturated or saturated fatty acids.
Conclusions and Clinical Relevance—Diets containing up to 66% of energy from fat were tolerated well by healthy cats and did not affect plasma lipid concentrations. Therefore, high-fat diets probably will not contribute to hypercholesterolemia or hypertriglyceridemia incats.
Objective—To develop a noninvasive method for the
in vivo assessment of flatulence in dogs.
Animals—8 adult dogs.
Procedure—Rectal gases were collected via a perforated
tube held close to each dog's anus and attached
to a monitoring pump fitted with a sensor that recorded
hydrogen sulfide concentrations every 20 seconds.
Patterns of flatulence were monitored for 14
hours after feeding on 4 days, and within- and
between-dog variation was assessed over 4 hours on
4 consecutive days. Rate of hydrogen sulfide production
(flatulence index) and frequency and number of
emissions were evaluated as potential indicators of
flatus characteristics. An odor judge assigned an odor
rating to each flatulence episode, and the relationship
between that rating and hydrogen sulfide concentration
Results—Flatulence patterns varied within and
between dogs. Variation was most pronounced for flatulence
index; mean coefficients of variance within
dogs over time and between dogs on each day were
75 and 103%, respectively. Flatus with hydrogen sulfide
concentrations > 1 parts per million could be
detected by the odor judge, and severity of malodor
was highly correlated with hydrogen sulfide concentration.
Odor ratings were accurately predicted by use of
the equation 1.51 × hydrogen sulfide concentration0.28.
Conclusions and Clinical Relevance—The technique
described in this report appears to provide sensitive,
reliable, and relevant data and will enable further
studies of the factors that influence flatulence in
dogs. Use of this technique also has the potential to
aid in investigations of colonic physiology and pathology.
(Am J Vet Res 2001;62:1014–1019).
Objective—To evaluate the effect of dietary supplementation with the probiotic strain Lactobacillus acidophilus DSM13241 in healthy adult cats.
Animals—15 adult cats.
Procedures—Cats were fed a nutritionally complete dry food for 5 weeks. Fecal character was assessed daily, and a single fecal sample and 3-mL blood sample were collected for bacterial enumeration and hematologic analysis, respectively. Cats were then fed the same diet supplemented with L acidophilus DSM13241 (2 × 108 CFU/d) for 4.5 weeks. Repeat fecal and hematologic measurements were taken prior to the return to control diet for a 4-week period.
Results—The probiotic species was recovered from feces, demonstrating survival through the feline gastrointestinal tract. Probiotic supplementation was associated with increased numbers of beneficial Lactobacillus and L acidophilus groups in feces and decreased numbers of Clostridium spp and Enterococcus faecalis, indicating an altered bacterial balance in the gastrointestinal tract microflora. Fecal pH was also decreased suggesting a colonic environment selective for the beneficial lactic acid bacterial population. Systemic and immunomodulatory effects were associated with administration of L acidophilus DSM13241 including altered cell numbers within WBC subsets and enhanced phagocytic capacity in the peripheral granulocyte population. In addition, plasma endotoxin concentrations were decreased during probiotic feeding, and RBCs had a decreased susceptibility to osmotic pressure.
Conclusions and Clinical Relevance—Probiotic strain L acidophilus DSM13241 fed at 2 × 108 CFU/d can alter the balance of gastrointestinal microflora in healthy cats. Furthermore, administration of this probiotic results in beneficial systemic and immunomodulatory effects in cats.
Objective—To determine whether feeding activated
charcoal, Yucca schidigera, and zinc acetate would
ameliorate the frequency and odor characteristics of
flatulence in dogs.
Design—In vitro screening of active agents followed
by a randomized controlled trial.
Animals—8 adult dogs.
Procedure—A fecal fermentation system was used
to assess the effects of activated charcoal, Yucca
schidigera, and zinc acetate alone and in combination
on total gas production and production of hydrogen
sulfide, the primary determinant of flatus malodor in
dogs. All 3 agents were subsequently incorporated
into edible treats that were fed 30 minutes after the
dogs ate their daily rations, and the number, frequency,
and odor characteristics of flatulence were measured
for 5 hours, using a device that sampled rectal
gases and monitored hydrogen sulfide concentrations.
Results—Total gas production and number and frequency of flatulence episodes were unaffected by any
of the agents. Production of hydrogen sulfide in vitro
was significantly reduced by charcoal, Yucca schidigera,
and zinc acetate by 71, 38, and 58%, respectively,
and was reduced by 86% by the combination of
the 3 agents. Consumption of the 3 agents was associated
with a significant decrease (86%) in the percentage
of flatulence episodes with bad or unbearable
odor and a proportional increase in the percentage
of episodes of no or only slightly noticeable odor.
Conclusions and Clinical Relevance—Results suggest that activated charcoal, Yucca schidigera, and
zinc acetate reduce malodor of flatus in dogs by altering
the production or availability of hydrogen sulfide in
the large intestine. (J Am Vet Med Assoc 2001;218:
Objective—To determine whether mild restriction of
food intake affects clinicopathologic variables, body
composition, and performance of dogs undertaking
intense sprint exercise.
Animals—9 trained healthy adult Greyhounds.
Procedure—Dogs were offered food free choice
once daily for 9 weeks until body weight and food
intake stabilized. Dogs were then randomly assigned
to be fed either 85% or 100% of this quantity of food
in a crossover study (duration of each diet treatment
period, 9 weeks). Dogs raced a distance of 500 m
twice weekly. Clinicopathologic variables were
assessed before and 5 minutes after racing; food
intake, weight, body composition, body condition
score, and race times were compared at the end of
each diet period.
Results—Compared with values associated with
unrestricted access to food, there were significant
decreases in mean body weight (by 6%) and median
body condition score (from 3.75 to 3.5 on a 9-point
scale) and the mean speed of the dogs was significantly
faster (by 0.7 km/h) when food intake was
restricted. Body composition and most clinicopathologic
variables were unaffected by diet treatment, but
dogs given restricted access to food had slightly
fewer neutrophils, compared with values determined
when food intake was unrestricted.
Conclusions and Clinical Relevance—Results indicate
that the common practice among Greyhound
trainers of mildly restricting food intake of racing dogs
to reduce body weight does improve sprint performance.
A body condition score of approximately 3.5
on a 9-point scale is normal for a trained Greyhound in
racing condition. (Am J Vet Res 2005;66:1065–1070)
Objectives—To determine the effects of racing and
training on serum thyroxine (T4), triiodothyronine (T3),
and thyroid stimulating hormone (TSH) concentrations
Animals—9 adult racing Greyhounds.
Procedure—Serum thyroid hormone concentrations
were measured before and 5 minutes after a race in
dogs trained to race 500m twice weekly for 6 months.
Resting concentrations were measured again when
these dogs had been neutered and had not raced for
3 months. Postrace concentrations were adjusted relative
to albumin concentration to allow for effects of
hemoconcentration. Thyroid hormone concentrations
were then compared with those of clinically normal
dogs of non-Greyhound breeds.
Results—When adjusted for hemoconcentration,
total T4 concentrations increased significantly after
racing and TSH concentrations decreased; however,
there was no evidence of a change in free T4 or total
or free T3 concentrations. Resting total T4 concentrations
increased significantly when dogs had been
neutered and were not in training. There was no evidence
that training and neutering affected resting
TSH, total or free T3, or free T4 concentrations.
Resting concentrations of T3, TSH, and autoantibodies
against T4, T3, and thyroglobulin were similar to those
found in other breeds; however, resting free and total
T4 concentrations were lower than those found in
Conclusions and Clinical Relevance—Except for
total T4, thyroid hormone concentrations in
Greyhounds are affected little by sprint racing and
training. Greyhounds with low resting total and free T4
concentrations may not be hypothyroid. (Am J Vet
Objective—To determine effects of increased dietary
protein and decreased dietary carbohydrate on hematologic
variables, body composition, and racing performance
Animals—8 adult Greyhounds.
Procedure—Dogs were fed a high-protein (HP; 37%
metabolizable-energy [ME] protein, 33% ME fat, 30%
ME carbohydrate) or moderate-protein (MP; 24% ME
protein, 33% ME fat, 43% ME carbohydrate) extruded
diet for 11 weeks. Dogs subsequently were fed
the other diet for 11 weeks (crossover design). Dogs
raced a distance of 500 m twice weekly. Rectal temperature,
hematologic variables before and after racing,
plasma volume, total body water, body weight,
average weekly food intake, and race times were
measured at the end of each diet period.
Results—When dogs were fed the MP diet, compared
with the HP diet, values (mean ± SD) differed
significantly for race time (32.43 ± 0.48 vs 32.61 ±
0.50 seconds), body weight (32.8 ± 2.5 vs 32.2 ± 2.9
kg), Hct before (56 ± 4 vs 54 ± 6%) and after (67 ± 3
vs 64 ± 8%) racing, and glucose (131 ± 16 vs 151 ±
27 mg/dl) and triglyceride (128 ± 17 vs 104 ± 28
mg/dl) concentrations after racing.
Conclusions and Clinical Relevance—Greyhounds
were 0.18 seconds slower (equivalent to 0.08 m/s or
2.6 m) over a distance of 500 m when fed a diet with
increased protein and decreased carbohydrate.
Improved performance attributed to feeding meat to
racing Greyhounds apparently is not attributable to
increased dietary protein and decreased dietary carbohydrate.
(Am J Vet Res 2001;62:440–447)