Objective—To compare urine composition in
Labrador Retrievers (LR) and Miniature Schnauzers
(MS) fed the same dog food.
Animals—8 healthy LR (mean [± SD] age, 3.1 ± 1.7
years) and 8 healthy MS (mean age, 3.7 ± 1.3 years).
Procedure—A nutritionally complete dry dog food
was fed to the dogs for 24 days. Urinary pH, volume,
specific gravity, frequency of urination, and urinary
concentrations of 12 analytes were measured for
each dog; urinary relative supersaturation (RSS) with
calcium oxalate and brushite (calcium hydrogen phosphate
dihydrate) were calculated from these values.
Results—MS urinated significantly less often and had
a lower urine volume (ml/kg of body weight per d) and
a significantly higher urine pH, compared with LR.
Urinary calcium concentration and brushite RSS were
significantly higher in the urine of MS. As a result of a
high calorie requirement, primarily as a result of high
surface area to volume ratio, MS had significantly
higher intake (per kg body weight) of dietary minerals,
compared with LR.
Conclusions and Clinical Relevance—Differences in
urine composition exist between breeds fed the same
diet, some of which, including lower urine volume,
higher calcium concentration, and higher brushite
RSS, may contribute to the high prevalence of calcium
oxalate uroliths observed in MS. Differences between
breeds should be considered when evaluating strategies
for controlling calcium oxalate stone formation.
(Am J Vet Res 2001;62:1782–1786)
Objective—To evaluate 3 commercially available
selected-protein-source diets as maintenance diets in
dogs with pruritus caused by adverse food reactions.
Design—Randomized crossover trial.
Animals—40 dogs > 6 months of age with pruritus
caused by adverse reactions to foods.
Procedure—Diagnosis was confirmed by use of diet
elimination and provocation studies. Subsequently,
dogs were fed 3 commercial diets for 3 weeks each
in a randomized, blinded, crossover trial. Dogs were
evaluated for pruritus, vomiting, diarrhea, and flatulence.
Results—Pruritus recurred in 52.5% of dogs fed a
chicken-rice diet, 47.5% of dogs fed a catfish-rice diet,
and 85% of dogs fed a venison-rice diet. Overall, 95%
of the dogs could be managed successfully with at
least 1 of the 3 diets.
Conclusions and Clinical Relevance—Results indicated
that commercially available limited-allergen
diets with selected protein sources may be appropriate
for long-term management of pruritus caused by
adverse food reactions. Testing of various protein
sources is usually required. (J Am Vet Med Assoc
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 determine prevalence of systolic
hypertension and associated risk factors in cats with
chronic renal failure evaluated in first-opinion practice.
Animals—103 cats with chronic renal failure.
Procedure—Systolic arterial blood pressure (SABP)
was measured with a noninvasive Doppler technique,
and cats that had SABP > 175 mm Hg on 2
occasions or that had SABP > 175 mm Hg and compatible
ocular lesions were classified as hypertensive.
Information from the history (previous treatment
for hyperthyroidism, age), physical examination
(sex, body weight), routine plasma biochemical
analyses (creatinine, cholesterol, potassium, sodium,
chloride, and calcium concentrations), and thyroid
status were evaluated as potential risk factors for
systolic hypertension. Variables associated with systolic
hypertension were evaluated by use of logistic
Results—20 (19.4%; 95% confidence interval, 13 to
28%) cats had systolic hypertension. Plasma potassium
concentration was significantly and inversely
associated with systolic hypertension.
Conclusions and Clinical Relevance—Prevalence of
systolic hypertension, although clinically important,
was lower than that reported previously. The cause of
the inverse association between systolic hypertension
and plasma potassium concentration is not yet
known. (J Am Vet Med Assoc 2002;220:1799–1804)
Objective—To assess the effect of dietary potassium
citrate supplementation on the urinary pH, relative
supersaturation of calcium oxalate and struvite
(defined as the activity product/solubility product of the
substance), and concentrations of magnesium, ammonium,
phosphate, citrate, calcium, and oxalate in dogs.
Animals—12 healthy adult dogs.
Procedure—Canned dog food was fed to dogs for 37
days. Dogs were randomly allocated to 3 groups and
fed test diets for a period of 8 days. Study periods
were separated by 6-day intervals. During each study
period the dogs were fed either standard diet solus
(control) or standard diet plus 1 of 2 types of potassium
citrate supplements (150 mg potassium citrate/kg
of body weight/d) twice daily. Urinary pH, volume and
specific gravity, relative supersaturation of calcium
oxalate and struvite, and concentrations of magnesium,
ammonium, phosphate, calcium, oxalate, and
citrate were assessed for each treatment.
Results—Mean urine pH was not significantly affected
by dietary potassium citrate supplementation,
although urine pH did increase by 0.2 pH units with
supplementation. Diets containing potassium citrate
maintained a higher urine pH for a longer part of the
day than control diet. Three Miniature Schnauzers had
a significantly lower urinary relative calcium oxalate
supersaturation when fed a diet supplemented with
potassium citrate, compared with control diet.
Conclusions and Clinical Relevance—Dietary
potassium citrate supplementation has limited
effects on urinary variables in most healthy dogs,
although supplementation results in maintenance of a
higher urine pH later in the day. Consequently, if supplementation
is introduced, dogs should be fed twice
daily and potassium citrate should be given with both
meals or with the evening meal only. (Am J Vet Res 2000;61:430–435)
Objective—To determine the dietary patterns and
intake of nutrients of concern in dogs with cardiac disease.
Animals—82 dogs with dilated cardiomyopathy
(DCM) or chronic valvular disease.
Procedure—Owners of dogs were contacted and
given a standardized telephone questionnaire regarding
diet and a 24-hour food recall to determine daily
intake of calories, protein, fat, sodium, potassium,
Results—Among the 82 dogs, 71% had no congestive
heart failure (CHF), and 29% had CHF or a history
of CHF. Sixty-one percent of dogs had concurrent
diseases. Anorexia was or had been evident in 34%
of dogs and was significantly more common in the
CHF group and in dogs with DCM. Most dogs (92%)
received some treats and table food, with a median
percentage of daily calories from treats of 19%
(range, 0% to 100%). Most owners (57%) that administered
pills used human or pet foods for pill administration.
Most dogs ate more than the Association of
American Feed Control Officials (AAFCO) minimum
values for fat and protein. Daily sodium intake varied
from 14 to 384 mg/100 kcal, compared with the
AAFCO minimum of 17 mg/100 kcal. A median of
25% of total daily sodium came from treats and table
food (range, 0% to 100%). Dogs with CHF ate significantly
more sodium, compared with dogs with no
Conclusions and Clinical Relevance—Dietary intake
for dogs with cardiac disease is highly variable and
often not optimal. (J Am Vet Med Assoc 2003;223:
Objective—To develop a standardized meal challenge test by assessing associations between food-withheld preprandial (ie, fasting) and postprandial triglyceride concentrations, determining the most appropriate sampling time to detect the peak concentration (highest postprandial concentration), and estimating reference intervals for fasting and postprandial concentrations in healthy dogs.
Animals—12 lean healthy mixed-breed dogs.
Procedures—Dogs were fed a dry commercially available diet (fat, 31% metabolizable energy) for 3 weeks. After food was withheld for 23 to 24 hours, plasma triglyceride concentrations were measured 1 and 0.083 hours before and 1, 2, 3, 4, 5, 6, 9, and 12 hours after feeding of a standardized challenge meal (median amount eaten, 63 kcal/kg [127 kcal/kg0.75]). Correlation and agreement between concentrations at peak and other time points were assessed by use of correlation coefficients and Bland-Altman limits of agreement. Reference intervals were calculated by use of a robust method.
Results—Fasting and peak triglyceride concentrations were not closely associated. The highest concentration among samples obtained 2, 5, and 6 hours after meal consumption had closest agreement with peak concentration. In 5 of 12 dogs, concentrations 12 hours after eating were still significantly above baseline concentration (mean of each dog's fasting concentrations).
Conclusions and Clinical Relevance—Fasting triglyceride concentration could not be used to accurately predict peak concentration. When estimating peak concentration, multiple samples should be collected 2, 5, and 6 hours after consumption of a standardized meal. Food may need to be withheld for > 12 hours when assessing fasting concentrations in healthy dogs.
Objective—To evaluate proteomic delineation of feline urine by mass spectrometry as a method for identifying biomarkers in cats at risk of developing azotemia.
Samples—Urine samples from geriatric cats (> 9 years old) with chronic kidney disease and nonazotemic cats that either remained nonazotemic (n = 10) or developed azotemia (10) within 1 year.
Procedures—Optimization studies with pooled urine were performed to facilitate the use of surface enhanced laser desorption-ionization time-of-flight mass spectrometry (SELDI-TOF-MS) for analysis of the urinary proteome of cats. Urine samples from nonazotemic cats at entry to the study were analyzed via SELDI-TOF-MS with weak cation exchange and strong anion exchange arrays. Spectral data were compared to identify biomarkers for development of azotemia.
Results—Low protein concentration in feline urine precluded direct application to array surfaces, and a buffer exchange and concentration step was required prior to SELDI-TOF-MS analysis. Three preparation conditions by use of weak cation and strong anion exchange arrays were selected on the basis of optimization studies for detection of biomarkers. Eight potential biomarkers with an m/z of 2,822, 9,886, 10,033, 10,151, 10,234, 11,653, 4,421, and 9,505 were delineated.
Conclusions and Clinical Relevance—SELDI-TOF-MS can be used to detect urinary low-molecular weight peptides and proteins that may represent biomarkers for early detection of renal damage. Further study is required to purify and identify potential biomarkers before their use in a clinical setting.
Objective—To evaluate urine cauxin immunoreactivity in geriatric cats with variable plasma creatinine concentrations and proteinuria and to assess urinary cauxin-to-creatinine concentration ratio (UC/C) as a predictor of developing azotemia.
Animals—188 client-owned geriatric (≥ 9 years of age) cats.
Procedures—A direct immunoassay was developed and validated for the quantification of urinary cauxin relative to a standard curve generated from a urine sample with high cauxin immunoreactivity. Relationships among UC/C, plasma creatinine concentration, and proteinuria were assessed. Nonazotemic cats were recruited and followed for 12 months. Urinary cauxin-to-creatinine concentration ratio was evaluated as a predictor of development of azotemia in these cats.
Results—No relationship was evident between UC/C and plasma creatinine concentration. A weak positive correlation was identified between UC/C and urine protein-to-creatinine concentration ratio (r = 0.212). At entry to the longitudinal study, those cats that later developed azotemia had a UC/C that was significantly higher than in those remaining nonazotemic after 12 months.
Conclusions and Clinical Relevance—The UC/C did not vary with severity of azotemia but appeared contributory to the feline urinary proteome. High UC/C values were predictive of the geriatric cats in our study developing azotemia. However, it seems unlikely that UC/C will provide additional information about the measurement of urine protein-to-creatinine concentration ratio as a biomarker for the development of azotemia in cats.