The American Academy of Veterinary Nutrition (AAVN) held its 15th Annual Clinical Nutrition and Research Symposium on June 3, 2015, in conjunction with the American College of Veterinary Internal Medicine Forum in Indianapolis, Indiana, USA. It was well-attended by an enthusiastic audience. Because many of the presenters at the symposium are veterinary nutrition residents or graduate animal nutrition students discussing their respective research projects, it is a terrific venue for up-to-date information on matters relating to pet food and pet nutrition.
Way, way back, I did my PhD dissertation on vitamin D metabolites in dogs with kidney disease, so anything remotely related to the subject always piques my interest. Therefore, I was pleasantly surprised to see three separate presentations on vitamin D at the meeting. One presenter found that at least in the small sample population studied (two dogs), the animals were able to maintain normal calcium status (as evidenced by serum ionized calcium, 25-hydroxyvitamin D and parathormone levels) with inclusion of plant-based ergocalciferol (Vitamin D2) in the food in lieu of the typical source of the vitamin in most dog foods (animal-based cholecalciferol, or vitamin D3). While this finding is not surprising (a study in 1939 reported that dogs can utilize the two forms of the vitamin with equal efficiency), it is good to be able to confirm this fact, so that formulators wishing to avoid animal-based ingredients have a viable alternative to use of cholecalciferol.
Another study analyzed the vitamin D3 content of 80 commercial dog foods on the market today. All except one product met the AAFCO minimum requirement on a calorie basis for adult maintenance, so as a rule it appears commercial products are a reliable source of this essential nutrient. While not specified in the written abstract, if I recall correctly from the oral presentation there was one product that in fact slightly exceeded the AAFCO vitamin D maximum. Regardless, assuming the new AAFCO Dog Food Nutrient Profiles are accepted in August, it is likely that a number of commercial formulations will need to be adjusted to bring them in line with the new, lower vitamin D maximum allowance.
Finally, a study looked at the relationship between vitamin D status and cancer. Dogs with some types of cancer (osteosarcoma and lymphoma), but not other types (mast cell tumors), had significantly lower serum 25-hydroxyvitamin D (the major pool of vitamin D in the body) than did healthy dogs, irrespective of dietary vitamin D intake. Whether the cancer is somehow involved in adversely affecting vitamin D metabolism or that low vitamin D status makes animals more susceptible to cancer merits further investigation.
Of course, many topics other than vitamin D were presented, but full discussion of the findings of each presentation cannot be accomplished via this brief synopsis. Besides my talk on some current pet food regulatory issues (including discussion on the impending changes to the AAFCO Dog and Cat Food Nutrient Profiles), two guest presenters spoke on obesity in horses and the safety of GMOs in food, respectively. There were a number of talks on the effects of probiotics and other dietary factors on the gut microflora, other intestinal parameters and other health factors. Several other presentations explored the effects of diet and water intake on urinary composition and health. Issues related to the nutritional management of various conditions (including osteoarthritis, cancer, obesity, hyperthyoidism, chylothorax and cardiac disease) were also presented.
Finally, other topics included:
· Plasma metabolic profiling in response to exercise in dogs fed an endurance diet
· Biomarkers in cats transitioning from lean to overweight body condition
· Effects of obesity on gene expression in fat tissue
· Nutritional education in European veterinary schools
· Effects of malnutrition in hospitalized patients
· Carbohydrate content of grain-free (vs. grain-containing) cat foods
· Perception by owners of a pet's body condition
· Serum fatty acid composition
Again, this column can't begin to adequately discuss these new findings. For those interested in the above topics but could not attend the meeting this year, the proceedings of the symposium are to be made available to members of AAVN. Eligibility for membership includes all veterinarians as well as animal nutritionists/scientists, so it is likely many employees of pet food companies would be qualified to join. Another benefit of membership is accessibility to the AAVN listserv, where participants can ask questions about or otherwise discuss timely topics in animal nutrition. More information about AAVN, including a membership application, is available on its web site (www.aavn.org).
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