Copper is an essential nutrient required for many physiological functions. Although copper deficiency and toxicity are rare in dogs because of complete and balanced commercial diets, cases of copper-associated hepatopathy (CAH) are reported to be increasing. CAH is characterized by copper accumulation in the liver, leading to oxidative damage, inflammation, and cirrhosis. Excessive copper accumulation can result from primary and secondary copper storage disorders. Management involves feeding a low-copper diet and providing copper chelation therapy. Regulatory changes and copper concentrations in pet food have raised concerns about the potential role of diet in this condition, highlighting the value of monitoring copper levels in ingredients and final products. Continued research is needed to better understand the factors contributing to CAH and optimize its prevention and management.<\/p>\n
Take-Home Points<\/strong><\/p>\n <\/div><\/div><\/p>\n Copper is an essential nutrient required in trace amounts.1<\/sup> It is a component of enzymes that play a role in many functions (e.g., bone and cartilage development, iron metabolism, hair color, connective tissue development).2 <\/sup>Although complete and balanced commercial diets ensure copper deficiency and toxicity are rare in dogs, cases of copper-associated hepatopathy (CAH)<\/a> can still occur due to excessive copper accumulation, which may be influenced by a variety of factors, including genetic mutations, dietary intake, and chronic hepatitis. This article will discuss copper deficiency, copper toxicity, nutritional considerations, nutritional management, and regulatory challenges.<\/span><\/p>\n Although copper is needed, cases of deficiency are uncommon. In 1991, copper deficiency was evaluated in 5 growing puppies that were fed a copper-free diet after weaning.3<\/sup> The first clinical signs occurred 3\u00a0months after feeding the copper-free diet and included loss of color in the pigmented hair around the face and head. After 4 months of eating the diet, hyperextension of the distal phalanges was noted in 4\u00a0of the dogs. After 6 months, hemoglobin and packed cell volume were lower in dogs fed the copper-free diet than those in the control group. In 2001, a case report described iatrogenic copper deficiency in a Bedlington terrier that was undergoing copper chelation.4<\/sup><\/span><\/p>\n Although onset of copper deficiency is slow, onset of severe copper toxicity is rapid in dogs fed very high doses. One dog given 165 mg\/kg PO of copper sulfate experienced vomiting and death 4 hours after ingestion.5<\/sup> As with copper deficiency, acute copper toxicity is uncommon; however, there is concern that the incidence of CAH has been increasing.6<\/sup> <\/span><\/p>\n CAH is a liver disease caused by excess accumulation of copper in the liver, which can result from increased dietary copper intake, defects in hepatic copper metabolism, or impaired ability to excrete copper through the biliary system.7<\/sup> Excess copper accumulation in the liver can result in oxidative damage of the hepatocytes, which leads to inflammation and eventual cirrhosis.7<\/sup> Copper accumulation in the liver can result from primary or secondary copper storage disorders.<\/span><\/p>\n Primary CAH is related to genetic mutations, including the COMMD1<\/i> mutation in Bedlington terriers and the ATP7B<\/i> mutation in Labrador retrievers.1<\/sup> Although specific genes have not been identified in other breeds, a heritable cause is suspected for Doberman pinschers, West Highland white terriers, Dalmatians, and Skye terriers.1<\/sup> In dogs with primary disorders, copper accumulation is centrilobular with concentrations typically exceeding 1000 ppm (normal copper concentration is considered to be less than 400 ppm).<\/span><\/p>\n In contrast, in dogs with secondary CAH, copper accumulation is periportal and is not linked to genetic mutations.7<\/sup> Dogs with secondary CAH accumulate copper as a result of chronic hepatitis or chronic, high dietary intake of copper.6<\/sup><\/span><\/p>\n Diagnosis of CAH is beyond the scope of this article. Information can be found at <\/span>go.navc.com\/404SJEk<\/span><\/a>.<\/span><\/p>\n The potentially increased prevalence of copper hepatopathy in dogs has veterinarians considering how diet may play a role. Suggested contributing factors are AAFCO<\/a> changes in regulations, including the requirement to use more bioavailable copper compounds and the removal of a maximum concentration.6,8<\/sup> Hepatic copper concentrations in dogs have been reported to be increasing over the past 15 to 20 years.6,8<\/sup> The dog\u2019s minimum copper requirements can be calculated using the AAFCO adult maintenance minimum (1.83 mg\/1000 kcal) and the dog\u2019s estimated ideal weight.9<\/sup> A study evaluating mineral content of 45\u00a0over-the-counter diets formulated for dogs determined that the median concentration of copper was 4.4 mg\/1000 kcal (range, 2.3 to 9 mg\/1000 kcal), and in none of the diets did copper fall below the AAFCO minimum requirement.10<\/sup> The median concentration is approximately 2.4 times the minimum requirement for adult maintenance. The highest copper concentration found (9 mg\/1000 kcal) was almost 5\u00a0times the minimum for adult maintenance.<\/span><\/p>\n Another factor to consider is that many dogs are overweight or obese<\/a> due to excessive calorie intake. Along with consuming excess calories, these dogs are also ingesting excessive amounts of nutrients, including copper, as shown in the following example.<\/span><\/p>\n Imagine a 36-kg (80-lb) Labrador retriever with a body condition score of 9 out of 9 (approximately 40% overweight). If the dog is consuming 1600 calories of a diet with a copper concentration of 9 mg\/1000 kcal, it would be consuming 14.4 mg of copper per day.<\/span><\/p>\n The dog\u2019s actual copper needs are based on the AAFCO minimum requirement and its estimated ideal weight. Because the dog is 40% overweight (140% of ideal weight), to determine its ideal weight, you would divide its current weight by 140% (or 1.4). Thus, the dog\u2019s ideal weight would be around 26 kg or 57 lb (36\u00a0kg\/1.4). For a dog of this weight, resting energy requirement (RER) would be approximately 806 kcal per day. If the dog consumed the ideal calorie amount from a diet meeting the AAFCO minimum copper requirement, it would ingest only about 1.5 mg of copper per day, which is significantly less than its current intake of 14.4\u00a0mg of copper per day.<\/span><\/p>\n Nutrition Math 101: Important Calculations<\/a><\/p><\/blockquote>\n\n
Copper Deficiency<\/h2>\n
Copper Toxicity<\/h2>\n
Primary Copper Hepatopathy<\/h3>\n
Secondary Copper Hepatopathy<\/h3>\n
Nutritional Considerations for CAH<\/h2>\n
Overweight\/Obesity<\/h3>\n
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