Emeritus James Law Professor of Internal Medicine Cornell University Ithaca, New York, United States
Disclosure(s):
Sharon A. Center, DVM, DACVIM (SAIM): No financial relationships to disclose
Presentation Description / Summary: There will be 7 focus points related to dietary copper (Cu) and Copper Associated Hepatopathy (CuAH): 1- Primary Care Practice Surveillance Study: prevalence of liver Cu accumulation in geriatric-end-of-life liver samples estimates risk for pet dog liver Cu accumulation and a safe range of Cu intake. 2: Preliminary Findings of a > 600 canine liver biopsy study (Cornell 2023 Database) estimates risk of liver Cu accumulation in dogs with suspected liver disease. 3. Comparison of liver Cu concentrations between pet dogs (lacking signs of liver disease) and free foraging canine surrogates (wolf-like clade canids: coyotes, wolves) implicate excessive Cu content in commercial dog foods. This data also implicates that the current canine reference range for liver Cu concentration have been amplified by dietary husbandry practices (contaminating foundational nutrients with over-formulated premix supplements). 4. Water Cu concentrations often are not critical as a source of Cu loading. 5. Accuracy of rhodanine stain for discovery of liver Cu accumulation and why staining cannot accurately predict liver Cu concentrations. 5. Genetic testing for ATP7(B & A) have dubious diagnostic value, even in Labradors, with unproven relevance in other breeds. 6. Safety of dietary Cu intake at 0.11 mg/100 kcal (dietary Cu level of two prescription liver diets, below NRC and AAFCO minimal intake) is proven safe and adequate in a 35 yr lifetime study of dogs with portosystemic shunts and portal vein atresia. 7. Collective findings advise safe modification of canine dietary Cu allowances by regulatory agencies (NRC, FDA, and AFFCO) and call for a labelling initiative to inform consumer purchases.
Learning Objectives:
: 1.Comprehend prevalence of liver Cu accumulation among Primary Care and Specialty Practice canine populations based on surveillance studies discussed. Understand how this may impact practice strategies (i.e., diagnostic testing for liver Cu accumulation. . Dietary Cu over-supplementation in commercial dog foods is implicated by comparison of liver Cu content between domestic dogs and wolf-like clade canids.
Understand utility of routine rhodanine staining (Cu specific stain) for canine liver biopsies that can advise modification of dietary husbandry. While "+" rhodanine staining (even a score of 1/5) is abnormal in any mammal, this is routinely encountered in canine liver biopsies. This finding implicates over-formulated premix additives in commercial diets. Positive rhodanine staining indicates need for tissue Cu quantification (digital or bench methods). Collective studies suggest overinflated Reference Intervals for canine liver Cu concentrations secondary to over-formulated premix additives. Arguing that population studies (kennel raised or pet dogs) have liver Cu concentrations within these reference limits does not negate concern about dietary Cu loading in commercial dog foods.
Reasonable dietary Cu limits are predicted from the discussed studies and historical data. How to effectively limit dietary Cu intake for individual dogs includes 1: how to use the USDA fooddata central website (for home prepared foods & snacks) and 2) how to acquire undisclosed commercial diet Cu concentration from manufacturers. Dietary Cu concentration must be normalized to ingested energy to allow comparisons among products. Transform dietary Cu mg/kg (dry matter basis) / kg of food by calculating kcal/kg of food and then using: (Cu mg/kg / kcal/kg) x 100 = Cu mg/100 kcal. The guideline suggested by the studies presented is between 0.11 to 0.24 mg/100 kcal.
