December 21, 2016

Learning ability in aged beagle dogs is preserved by behavioral enrichment and dietary fortification: a two-year longitudinal study

N.W. Milgrama,∗, E. Head b, S.C. Zicker c, C.J. Ikeda-Douglas a, H. Murphey d, B. Muggenburg d, C. Siwak a, D. Tapp a, C.W. Cotman b, Elsevier, 2004

The study is trying to determine the effects that behavioral enrichment, with increased exercise, environmental enrichment, and a program of cognitive enrichment, and dietary fortification with antioxidants have on cognitive and learning ability in aged Beagle dogs. Dogs have been shown to endure age related cognitive decline similar to humans. Previous studies on canine cognitive aging have been comparing the cognitive abilities of young dogs to aged dogs while this study focuses on aged dogs. It was hypothesized that both the behavioral enrichment and dietary supplementation treatments would have beneficial effects on cognitive function, and that both treatments used simultaneously would be more effective than either treatment by itself. Therefore, I predicted that the group of dogs with the antioxidant fortified food and the behavioral enrichment would have the highest scores on cognitive tests. 48 old and 17 young beagle dogs were evaluated by a variety cognitive tests over 9 months. Performance on these cognitive tests was used to divide the aged dogs into four cognitively similar groups of 12 dogs each. One group was fed a control diet and received a control experience, one group was fed control food and received a program of enriched experience, one group was fed a diet fortified  by antioxidants and received a control experience, the final group was fed the fortified diet and given the enriched experience. A year after the start of the experiment, all dogs were tested on both a size discrimination and a reversal learning task. After the two year period, all animals were tested on a black/white discrimination learning task.

The results demonstrated that both discrimination and reversal learning ability decline as the dog ages, but the rate of this decline can be delayed by both behavioral enrichment and an antioxidant fortified diet. This was the first study to look at the effects of both treatments combined and it found that using both treatments was far more effective than either one by itself.

Reviewed by Jonathan Guzman