Copper metabolism and its implications for canine nutrition.

Canine copper nutrition has received increased attention due to recent reports of apparent copper-associated hepatitis in the USA and European Union. In order to properly address the need to modify the U.S. National Research Council and Association of American Feed Control Officials canine copper recommendations that will have implications for all dogs, it is important to understand the complexities of copper metabolism, confounding variables affecting copper status, and the available research on this topic in dogs. Recent trends in consumer preference for dog diets, supplements, and functional treats introduce another layer of complexity, as most ingredients used in these formulations provide vastly different proportions of essential nutrients, thus resulting in great variation in nutrient profiles available to the animal. Although controlled research addressing copper metabolism in dogs is limited, there are lessons to be learned from other monogastric species as well as canine case studies that can provide a base for increasing knowledge to address this issue. Copper metabolism and status in animals is affected by a multitude of factors including absorption, storage, excretion, and nutrient interactions. Given its vital role in many physiological processes, it is important that both nutritional deficiencies and toxicities be avoided. Additionally, another challenge for proper copper nutrition in dogs is the known genetic predispositions of some breeds for copper storage and excretion abnormalities. Therefore, it is imperative that veterinarians, nutritionists, and pet food manufacturers collaborate with the shared goal of providing dog food options that supply the essential nutrients at adequate concentrations to support an active and healthy life. Many questions remain regarding copper metabolism and proper diet formulation for dogs. Future research efforts should focus on discovering reliable, non-invasive methods for evaluating canine copper status, a deeper understanding of genetic predispositions of certain breeds, increased knowledge of copper contributions from various ingredients, and the role of unpredictable physiological stressors on copper metabolism.

Evaluation of a performance enhancing supplement in American Foxhounds during eventing.

Enhancing performance through dietary measures is constantly sought as some supplements have shown modest performance enhancement in rodents and human subjects. To evaluate a proprietary dietary supplement, a study was undertaken to assess the effect of diet and exercise on blood physiological parameters during a tracking American Fox Hound field championship. Ten dogs were assigned to two different groups. Group A received a commercial kibble and Group B received the same diet with the addition of a supplement added to the dietary premix for 4 weeks before the field event. Blood was collected at rest, immediately following days 1 and 2 of the event and 48 h after day 2. Blood chemistry, complete blood cell counts and cortisol concentrations were analysed. Competition performance was also documented for all dogs using a points system for tracking events. Many chemistry parameters and blood cell counts changed significantly due to exercise. Differences between the dietary groups showed that Group B had significantly lower aspartate aminotransferase on days 1 and 2 of exercise and lower creatine kinase on day 2. Based on tracking scores, dogs in Group B out-performed dogs in Group A. This study suggests that endurance hunting dogs develop changes in serum markers of musculoskeletal integrity that might be mitigated by the addition of the supplement, resulting in better performance. Although intriguing, follow-up controlled studies are needed to ensure that the enhanced performance was not biased due to lack of randomisation.