Procedure—Soy isoflavone content of each food was
determined by use of acid-methanol hydrolysis and
high-pressure liquid chromatography with ultraviolet
absorbance detection. Isoflavones were identified
and quantified by reference to authentic standards.
Results—Genistein and daidzein were the major soy
isoflavones identified in 24 of 42 foods, with concentrations
ranging from 1 to 163 µg/g of food. Foods
labeled as containing soybean solids (16/42) had
isoflavone concentrations > 11 µg/g. More dry (13/14)
and semimoist (6/6) foods contained isoflavones than
moist foods (5/22). Isoflavone content and food cost
were negatively correlated for dry and semimoist
foods but not for moist foods. Total amount of
isoflavone consumed by cats fed these soy-containing
foods as a sole maintenance diet was estimated
to be between 0.6 and 4.5 mg/kg of body weight/d,
which is comparable to concentrations in humans that
result in a measurable although modest effect on
serum concentrations of steroid and thyroid hormones.
Conclusions and Clinical Relevance—Genistein and
daidzein are common constituents of commercial cat
foods. Predictors of isoflavone content included ingredient
labeling, food type, and food cost. Soy
isoflavones in some commercial cat foods were
detected in amounts predicted to have a biological
effect. (Am J Vet Res 2002;63:181–185)
Objective—To determine range of calorie density and feeding directions for commercially available diets designed for weight management in dogs and cats.
Sample Population—93 diets (44 canine diets and 49 feline diets) that had a weight management claim with feeding directions for weight loss or implied weight management claims.
Procedures—Calorie density was collected from product labels or by contacting manufacturers. Recommended feeding directions for weight loss were compared with resting energy requirement (RER) for current body weight by use of a standard body weight (36.4 kg [80 lb] for canine diets and 5.5 kg [12 lb] for feline diets).
Results—Calorie density for the 44 canine diets ranged from 217 to 440 kcal/cup (median, 301 kcal/cup) and from 189 to 398 kcal/can (median, 310 kcal/can) for dry and canned diets, respectively. Calorie density for the 49 feline diets ranged from 235 to 480 kcal/cup (median, 342 kcal/cup) and from 78 to 172 kcal/can (median, 146 kcal/can) for dry and canned diets, respectively. Recommended calorie intake for weight loss in dogs ranged from 0.73 to 1.47 × RER (median, 1.00 × RER) and for weight loss in cats ranged from 0.67 to 1.55 × RER (median, 1.00 × RER). Diets ranged from $0.04 to $1.11/100 kcal of diet (median, $0.15/100 kcal of diet).
Conclusions and Clinical Relevance—Wide variation existed in recommended calorie intake, kilocalories, and cost for diets marketed for weight loss in pets. This variability could contribute to challenges of achieving successful weight loss in pets.
Objective—To determine the proportion of dog breeders who fed diets meeting the Association of American Feed Control Officials regulations for nutritional adequacy for reproduction and growth and to investigate factors that influenced feeding practices of breeders.
Design—Web-based cross-sectional survey.
Sample—2,067 dog breeders from the United States and Canada.
Procedures—A self-administered, anonymous, Web-based questionnaire was used to collect information on breeder demographics and feeding practices during 3 life stages of dogs: adult maintenance for nonpregnant dogs, gestation-lactation, and puppy growth. Appropriateness of commercial diets for each life stage was determined by respondent-reported nutritional adequacy statements on product labels. Data were also collected regarding breeder criteria for diet selection and sources of nutrition information.
Results—A substantial number of breeders reported feeding commercial diets not intended for that life stage during gestation-lactation (126/746 [16.9%]) and puppy growth (57/652 [8.7%]). Additionally, approximately one-seventh of breeders reported feeding home-prepared diets for ≥ 1 life stage. Unsubstantiated health and marketing information influenced diet selection of many breeders. Veterinarians, although generally viewed as a trusted source of nutrition information, were consulted by only 823 of 1,669 (49.3%) breeders and were viewed less favorably by breeders feeding home-prepared diets, compared with the opinion of breeders feeding commercial diets.
Conclusions and Clinical Relevance—Veterinarians should consider taking a more proactive role in directing dog breeders and other pet owners toward scientifically substantiated sources of diet information and in explaining the importance of current nutritional standards for reproduction and early development of dogs.
Objective—To determine whether subcutaneous fat thickness measured on thoracic radiographs was associated with body condition score (BCS) in dogs.
Animals—87 client-owned dogs (41 males and 46 females) with a median age of 10.0 years (range, 1 to 16 years) and median weight of 20.3 kg (range, 3.1 to 58.0 kg).
Procedures—Age, sex, body weight, and breed were recorded. Body condition scores (scale from 1 to 9) and muscle condition scores were assigned by a single investigator. Subcutaneous fat thickness was measured at the level of the eighth rib head on a dorsoventral or ventrodorsal radiographic view of the thorax by a single investigator. Ratios of subcutaneous fat thickness to the width of the midbody of T8 on the ventrodorsal or dorsoventral radiographic view (T8 ratio) and to the length of the midbody of T4 on a right lateral radiographic view (T4 ratio) were calculated and compared with BCS by means of the Spearman correlation method.
Results—Median BCS was 6 (range, 1 to 9), and all muscle condition scores were represented. There were significant correlations between BCS and T4 ratio (r = 0.86) and between BCS and T8 ratio (r = 0.84).
Conclusions and Clinical Relevance—Results indicated that in this population, there was a significant association between BCS and subcutaneous fat thickness measured on thoracic radiographs. Findings suggested that measuring subcutaneous fat thickness could aid in the retrospective assignment of BCS in studies involving dogs in which BCS was not recorded in the medical record.
OBJECTIVE To determine whether the degree of CT attenuation of muscle would differ between healthy old and young dogs.
ANIMALS 10 healthy old (> 8 years old) and 9 healthy young (1 to 5 years old) Labrador Retrievers with a body condition score of 5 or 6 on a 9-point scale.
PROCEDURES CT was performed with the dogs mildly sedated. A freehand closed polygon tool was used to define the outer margin of the left epaxial muscles on each transverse image obtained from the cranial to caudal endplates of T13. The CT attenuation values from every voxel from within these regions of interest were exported from DICOM software as a single dataset in an extensible markup language file. From these data, mean CT attenuation values were calculated for each dog and these mean values were compared between age groups.
RESULTS Mean CT attenuation values for the epaxial muscles were significantly lower in old dogs than in young dogs. A significant negative correlation (r = –0.74) was identified between mean CT attenuation values and dog age.
CONCLUSIONS AND CLINICAL RELEVANCE In addition to loss of skeletal muscle mass, low muscle CT attenuation values suggested that the old dogs in this study also had greater muscle fat content than did young dogs. Additional studies are warranted to evaluate qualitative and quantitative muscle changes in old dogs.
Objective—To evaluate clinically applicable methods of assessing lean body mass in dogs and compare muscle mass and inflammatory markers in healthy young and old dogs.
Animals—9 healthy young (1 to 5 years old) and 10 old (> 8 years old) Labrador Retrievers with a body condition score of 5 to 6 of 9.
Procedures—Radiography of the thoracolumbar region was performed for measurement of epaxial muscle height at the level of T13–L1. Computed tomographic images were obtained for the measurement of the epaxial and temporal muscles. Ultrasonography also was performed for regional muscle measurements at these same sites and the quadriceps muscle. Serum C-reactive protein, insulin-like growth factor-1, and tumor necrosis factor-α concentrations also were measured, and dogs' activity for 14 days was assessed with an activity monitor.
Results—Mean epaxial muscle area measured by ultrasonography was significantly lower in the old group, compared with the young group, whereas epaxial muscle area measured by CT was only significantly lower in the old group after normalization for vertebral height. Neither temporal and quadriceps muscle measurements nor serum C-reactive protein or insulin-like growth factor-1 concentrations were significantly different between age groups. Tumor necrosis factor-α concentrations were undetectable in all dogs.
Conclusions and Clinical Relevance—This study documented reduced epaxial muscle area in healthy old Labrador Retrievers, consistent with the syndrome of sarcopenia. Ultrasonography and CT were feasible methods of measuring epaxial muscle area, but much additional research is required to assess this method. A better understanding of underlying mechanisms of sarcopenia as well as methods for slowing progression is needed.
Objective—To measure thiamine concentrations in commercial canned foods formulated for cats as an initial assessment of the variation among canned foods and to determine the effects of flavor (fish vs nonfish) of the food, texture (paté vs nonpaté) of the food, country of manufacture, and size of the company on thiamine concentration.
Design—Prospective cross-sectional study.
Sample—90 canned, nontherapeutic diets formulated for cats (1 fish and 1 nonfish flavor for each of 45 brands).
Procedures—Each canned food was homogenized, and thiamine concentration was analyzed with a fluorometric method.
Results—Thiamine concentration was below the minimums of the Association of American Feed Control Officials in 12 of 90 (13.3%) foods and below the recommended allowance of the National Research Council in 14 of 90 (15.6%) foods. Paté foods had significantly lower thiamine concentrations than did nonpaté foods, and foods from smaller companies had significantly lower thiamine concentrations, compared with concentrations in foods from larger companies. Flavor of food and country of manufacture were not significantly associated with thiamine concentration.
Conclusions and Clinical Relevance—A wide range of thiamine concentrations was found in the foods evaluated. Thiamine concentration in a substantial percentage of commercially available canned foods was below the amount recommended for adult cats. Additional research on interlot and intralot variation in thiamine concentrations of foods formulated for cats is warranted. Companies should implement strict quality control and analysis practices regarding food products. Clinicians should consider thiamine deficiency as a differential diagnosis in a cat with acute neurologic dysfunction.
Objective—To compare morphometric measurements and serum insulin-like growth factor (IGF-1) concentration in cats with and without hypertrophic cardiomyopathy (HCM), and assess the hypothesis that cats with HCM have larger body size and skeletal features and higher serum IGF-1 concentrations than healthy cats.
Animals—25 cats with HCM and 22 healthy control cats.
Procedures—Physical examination and echocardiography were performed to classify cats into the HCM and control groups. Data collected from each cat included diet history, body weight, body condition score, lengths of the humerus and 4th and 12th thoracic vertebrae, heart size, head length and width, and abdominal circumferences. Comparisons of these variables were made between groups.
Results—Body condition score in HCM-affected and control cats did not differ significantly. However, median head width; lengths of the head, 4th and 12th thoracic vertebrae, and humerus; and body weight in the HCM-affected group were significantly greater than values in the control group. Median serum concentration of IGF-1 was not significantly different between groups.
Conclusions and Clinical Relevance—These data suggested that among the study cats, those with HCM were skeletally larger, but not more obese, than healthy cats. Whether this was attributable to differences in early growth or other causes requires additional investigation.