Jennifer A. Larsen

Heavy metals have been documented in dietary supplements for people and animals. Cadmium, selenium, lead, and mercury are of particular concern. Our objective was to determine the concentrations of five essential minerals and 12 heavy metals in 70 canine and feline dietary supplements, and to evaluate potential toxicity risks. Our secondary objective was to compare the analysed concentrations to the content claims on product labels. Samples were analysed using inductively coupled plasma mass spectrometry. Concentrations were compared to maximum tolerable levels (MTL) established by the National Research Council. Beryllium, mercury, and thallium were not detected in any supplements. The most prevalent essential mineral was zinc (68 products). The most prevalent heavy metal was nickel (66 products); lead was detected in 16 supplements (median 0.145 mg/kg; 0.1–3.7 mg/kg) and cadmium was detected in 10 supplements (median 0.115 mg/kg; 0.1–1.5 mg/kg). Selenium, an essential nutrient with a narrow margin of safety, was detected in 52 samples (median 0.32 mg/kg; 0.1–14.0 mg/kg) but only declared as an ingredient in 10 products. Of 18 supplements with label claims for one or more of the minerals analysed, eight did not meet one or more claims. None of the analysed supplements exceeded the MTL for any mineral, suggesting that the risks are low when following label directions. However, species‐specific MTL data are lacking for many minerals in dogs and cats, necessitating extrapolation with safety factors. More research is needed to characterise the risks of chronically high intakes of minerals by dogs and cats. Data presented as an oral abstract at the American Academy of Veterinary Nutrition 24th Annual Clinical Nutrition & Research Symposium and the 28th European Society of Veterinary & Comparative Nutrition Congress 2024.

Background: Androgen-dependent cystinuria has been described in intact male dogs. Castration has been recommended to reduce urinary cystine excretion. Hypothesis/Objectives: Urinary cystine/creatinine concentration will significantly decrease in dogs with suspected androgen-dependent (Type III) cystinuria after castration and will be associated with a lack of sonographic evidence of urolithiasis. Animals: Six intact male dogs with cystine uroliths. Methods: Prospective, observational study. Urinary amino acid/creatinine concentrations and abdominal ultrasound were evaluated at baseline (T0), 30 days (T30), and 90 days (T90) after castration and urolith removal. No dietary change was recommended unless urolith recurrence was noted. DNA was evaluated for the cystinuria-associated marker for Type III cystinuria. Results: The median decline in urinary cystine/creatinine (uCys/creat) concentration from T0 to T30 was 577 nmol/mg (IQR, 415–969; p = 0.03), from T0 to T90 was 798 nmol/mg (IQR, 580–989; p = 0.03) and from T30 to T90 was 34 nmol/mg (IQR, 19.5–443; p = 0.03). Two dogs had small (2.5–3 mm) uroliths at T30, which resolved in one of them at T90. Both dogs with ultrasonographic evidence of recurrence at T30 were positive for the cystinuria-associated genetic marker, although no signs of lower urinary tract disease were noted in either dog. Three of 6 enrolled dogs were homozygous positive for the genetic marker. Conclusions and Clinical Importance: Castration should be considered for intact male dogs with cystine urolithiasis.

Background: Edible oils often are included in recipes for home-prepared pet diets to supply essential fatty acids, but there may be discrepancies between database values and oil profiles. Furthermore, storage time and conditions influence quality. Hypothesis/Objectives: Determine the fatty acid profiles of commonly used oils and characterize fatty acid oxidation under recommended storage conditions. Samples: Fourteen products were purchased and stored according to label instructions, representing 2 brands each of walnut, corn, canola, and flaxseed oils, and 3 each of safflower and sunflower oils. Methods: Samples were collected at baseline and at 6 and 12 months and stored at −80°C until analysis. Aliquots were analyzed for fatty acid profile at baseline and 12 months, and at all 3 timepoints for free fatty acidity, peroxide value, and induction time. Results: Linoleic acid concentrations exceeded the United States Department of Agriculture (USDA) Food and Nutrient Database for Dietary Studies (FNDDS) values except for 2/3 sunflower and 1/3 safflower oil samples. Peroxide value was static for 3/14 products and significantly increased at 6 or 12 months for 11/14 products. Induction time was static for 2/14 products and significantly decreased at 6 or 12 months for 12/14 products. Conclusions and Clinical Importance: Sunflower and safflower oils are not reliable sources of linoleic acid. Cold storage appeared to better maintain oil quality. Oils for home-prepared pet foods should be carefully selected to ensure nutritional adequacy and refrigerated to maintain quality, especially those high in polyunsaturated fatty acids, high omega-6:omega-3 ratios, or both.

Background: Monitoring serum phosphorus concentrations is crucial in the management of chronic kidney disease in cats. The diurnal variation of serum phosphorus concentration may affect clinical assessment. Hypothesis/Objectives: Characterize the diurnal variation of serum phosphorus concentration in cats and determine the associations between changes in serum phosphorus concentration and several metabolites of phosphorus metabolism. Animals: Six apparently healthy, intact male, specific-pathogen-free cats were housed in a photoperiod, humidity, and temperature-controlled facility. Methods: Blood sampling was performed hourly for 24 hours to obtain the serum concentrations of phosphorus, ionized calcium, parathyroid hormone, and calcidiol. Results were analyzed using linear mixed-effect models to determine the significance of diurnal variation and associations between serum phosphorus concentrations and other metabolites over time. Results: Diurnal variation in serum phosphorus concentration was noted with an apex around 11:00 followed by gradually declining concentrations to reach the nadir around 23:00. The serum phosphorus concentration again increased through the early morning on the next day. An approximately 25% difference in serum phosphorus concentration at the apex and the nadir was documented. A non-linear relationship between the serum concentrations of phosphorus and ionized calcium over time was identified. Conclusions and Clinical Importance: Diurnal variations of serum phosphorus concentration and associations between the trending of serum phosphorus and ionized calcium concentrations were evident in a group of clinically healthy adult cats housed in a controlled environment. These findings can help in the interpretation of clinical and research data regarding calcium and phosphorus metabolism and kidney health in cats.

Background: Many dog owners alter their dog's nutritional regimen after a diagnosis of cancer. There are limited data as to specific changes made and reasons behind these changes. Hypothesis/Objectives: To collect updated and detailed data on changes made by owners to their dog's diet and supplements after a cancer diagnosis. Animals: Responses were collected from a survey of dog owners who brought their dogs to the UC Davis Veterinary Medical Teaching Hospital's Oncology Service for the first time after a cancer diagnosis. Dogs with recurrence or presenting for a second type of cancer were excluded. Methods: Eligible owners were surveyed between December 2020 and March 2022. The survey contained 62 questions regarding diet, supplement use, and treats, and how these were altered after a cancer diagnosis. Responses were matched to medical record data. Results: One hundred twenty-eight surveys were retained for analysis, including 120 respondents that completed the survey. In response to a cancer diagnosis, 54.8% (95% CI; 45.7%-63.8%) of owners altered diets or supplements or both. The most common informational resource for dog diets was veterinarians (53.9%). Usage of home-prepared foods significantly increased after a cancer diagnosis (P = .03). There was no significant difference in commercial diet usage before or after a diagnosis (P = .25). Joint support products were the most common supplements given both before (37.4%) and after (35.0%) diagnosis. Conclusions and Clinical Importance: Many dog owners alter their dog's nutritional intake after a cancer diagnosis. These owners should be provided information relating to commonly observed alterations, including home-prepared foods and supplements.

Background: The impact of undernutrition in dogs with protein-losing enteropathy (PLE) caused by inflammatory enteritis, intestinal lymphangiectasia, or both and which variables are most predictive of outcome are unknown. Objectives: Develop an undernutrition screening score (USS) for use at the time of diagnosis of PLE in dogs, which is predictive of outcome. Animals: Fifty-seven dogs with PLE prospectively recruited from 3 referral hospitals in the United Kingdom. Methods: An USS based on the presence and severity of 5 variables: appetite, weight loss, and body, muscle, and coat condition and scored out of 15, with higher scores reflecting worse undernutrition, was calculated at the time of diagnosis. Follow-up information was obtained for at least 6 months. Results: Dogs that failed to achieve clinical remission within 6 months had higher USS at diagnosis compared with dogs that achieved remission (median, 7.5; range, 2-14 and median, 5; range, 0-14, respectively). The USS at diagnosis gave an area under the receiver operating characteristic curve (AUC) of 0.656 for predicting nonclinical remission within 6 months, whereas a score consisting of just epaxial muscle loss and coat condition resulted in a larger AUC of 0.728. Conclusions and Clinical Importance: Of the 5 variables assessed in the USS, a combination of epaxial muscle loss and coat condition was most predictive of not achieving clinical remission within 6 months in dogs with PLE. Additional studies will help determine the effect of changes in USS and the 5 associated variables after diagnosis on outcome variables in these dogs.

Feeding an elimination diet exclusively is currently the only accurate diagnostic test for an adverse food reaction in dogs and cats. However, owner compliance has been identified as a challenge, and the inability to limit exposure to other items (including treats and supplements) is a remarkable reason for failure. The objective of the current study was to evaluate the presence of declared and undeclared mammalian deoxyribonucleic acid (DNA) in commercially available canine treats and supplements using polymerase chain reaction methodology. Eight treat products and 20 supplement products were analyzed for the DNA of 10 mammalian species (bison, cat, cow, dog, goat, horse, mouse, rat, pig, and sheep). The results showed that 88% (7/8) of treats and 40% (8/20) of supplements were found to contain at least one source of undeclared mammalian DNA. Undeclared pig and cow DNA were the most frequently identified, and there were only two instances of negative results for declared species. Because of the frequent finding of undeclared mammalian DNA in the assessed products, avoiding using treats and supplements during elimination trials is recommended.