Antioxidant-fortified diet and behavioral enrichment in aged beagles (longitudinal study)
A longitudinal controlled study in beagles tested an antioxidant-fortified food and a program of behavioral enrichment, alone and combined, against control food and a control environment in a 2 x 2 factorial design. Forty-eight aged dogs (9-12 years) were assigned from baseline cognitive scores into four cognitively equivalent groups of 12, with additional groups of young dogs. Discrimination and reversal learning were tested after 6 months, 1 year and 2 years of treatment; the combined-treatment group learned more accurately than the other aged groups at one and two years, enrichment improved discrimination learning, and both treatments improved reversal learning. An immune sub-analysis of 21 dogs found neutrophil phagocytosis significantly increased in dogs receiving both treatments.
Record
| Design | controlled trial |
|---|---|
| Status | completed |
| Intervention | Antioxidant-fortified food (a broad spectrum of antioxidants and mitochondrial enzymatic cofactors) and a program of behavioral enrichment (increased exercise, environmental enrichment, and a series of learning tasks), alone and combined in a 2 x 2 factorial design |
| Intervention class | combination |
| Comparator | Control food and control (normal level) environment |
| Duration | 2-year longitudinal study; cognitive testing after 6 months, 1 year and 2 years of treatment |
| Dogs | 48 |
| Population note | 48 aged dogs assigned to four groups of 12 (CC, CE, AC, AE); two additional groups of young behaviorally enriched dogs (control or fortified food); the immune sub-analysis reports n=21 geriatric dogs |
| Breed | Beagle |
| Age | 9-12 years (aged groups) |
| Other | Aged groups were formed as cognitively equivalent from baseline performance on a battery of cognitive tests |
| Primary outcome | Discrimination and reversal learning (oddity discrimination after 6 months; size discrimination and reversal after 1 year; black/white discrimination after 2 years); neutrophil phagocytosis and lymphocyte proliferation in an immune sub-analysis |
| Result (as reported) | At one and two years, the aged combined treatment group showed more accurate learning than the other aged groups. Discrimination learning was significantly improved by behavioral enrichment. Reversal learning was improved by both behavioral enrichment and dietary fortification. By contrast, the fortified food had no effect on the young dogs. In the immune sub-analysis, neutrophil phagocytosis was significantly increased in dogs receiving both dietary antioxidants and cognitive enrichment. |
| Tags | cognition, antioxidant-diet, enrichment, beagle, immunosenescence, longitudinal |
Notes: Grouped as one study: the 2004 and 2005 papers report the 1-year and 2-year cognitive results of the same longitudinal investigation, the 2006 paper reports an immune sub-analysis of its 2-year cohort (n=21), and the 2007 and 2009 reviews summarise the same intervention study. The 2002 paper reports the 6-month oddity-discrimination results in old and young dogs fed the same antioxidant-fortified food; its abstract does not mention the enrichment arm. Groups were formed as cognitively equivalent from baseline scores and randomization is not stated, so kind is recorded as controlled_trial. Setting, dose, funding and study dates are not stated in the abstracts.
Sources and verbatim quotes
Dietary enrichment counteracts age-associated cognitive dysfunction in canines. (2002) PMID 12392778 (results)
we studied the effects of dietary antioxidants and age in a canine model of aging that parallels the key features of cognitive decline and neuropathology in humans
Old and young animals were placed on either a standard control food, or a food enriched with a broad spectrum of antioxidants and mitochondrial enzymatic cofactors.
After 6 months of treatment, the animals were tested on four increasingly difficult oddity discrimination learning problems.
However, this age-associated decline was reduced in the animals fed the enriched food, particularly on the more difficult tasks.
Long-term treatment with antioxidants and a program of behavioral enrichment reduces age-dependent impairment in discrimination and reversal learning in beagle dogs. (2004) PMID 15130670 (design)
The effects of long-term treatment with both antioxidants and a program of behavioral enrichment were studied as part of a longitudinal investigation of cognitive aging in beagle dogs.
Baseline performance on a battery of cognitive tests was used to assign 48 aged dogs (9-12 years) into four cognitively equivalent groups, of 12 animals per group: Group CC (control food-control environment), group CE (control food-enriched environment); Group AC (antioxidant fortified food-control environment); Group AE (fortified food-enriched environment).
We also tested a group of young dogs fed the control food and a second group fed the fortified food. Both groups of young dogs received a program of behavioral enrichment.
To evaluate the effects of the interventions on cognition after 1 year, the dogs were tested on a size discrimination learning task and subsequently on a size discrimination reversal learning task.
Both tasks were also improved by both the fortified food and the behavioral enrichment. However, in both instances the treatment effects largely reflected improved performance in the combined treatment group.
Learning ability in aged beagle dogs is preserved by behavioral enrichment and dietary fortification: a two-year longitudinal study. (2005) PMID 15585348 (results)
The effectiveness of two interventions, dietary fortification with antioxidants and a program of behavioral enrichment, was assessed in a longitudinal study of cognitive aging in beagle dogs.
Discrimination learning and reversal was assessed after one year of treatment with a size discrimination task, and again after two years with a black/white discrimination task.
At one and two years, the aged combined treatment group showed more accurate learning than the other aged groups. Discrimination learning was significantly improved by behavioral enrichment. Reversal learning was improved by both behavioral enrichment and dietary fortification. By contrast, the fortified food had no effect on the young dogs.
These results suggest that behavioral enrichment or dietary fortification with antioxidants over a long-duration can slow age-dependent cognitive decline, and that the two treatments together are more effective than either alone in older dogs.
Dietary antioxidants and behavioral enrichment enhance neutrophil phagocytosis in geriatric Beagles. (2006) PMID 16806493 (sub-analysis)
The study objective was to determine the effects of feeding food enriched in antioxidants and a program of environmental/cognitive enrichment on selected ex vivo assays of inflammatory and immune cells in healthy geriatric Beagle dogs (n=21).
Four groups of dogs were tested using a 2 x 2 factorial design. The 2-year longitudinal study included both nutritional (control food or antioxidant-fortified food) and behavioral (normal level or cognitive enrichment) interventions. Behavior enrichment included increased exercise, environmental enrichment, and a series of learning tasks.
Phagocytosis of opsonized latex-coated beads by peripheral blood neutrophils was measured by flow cytometry and found to be significantly increased in dogs receiving both dietary antioxidants and cognitive enrichment.
Combining an antioxidant-fortified diet with behavioral enrichment leads to cognitive improvement and reduced brain pathology in aging canines: strategies for healthy aging. (2007) PMID 17717087 (review)
We present additional evidence that, in a canine model of aging, combining an antioxidant-enriched diet and behavioral enrichment (including social, physical, and cognitive components) can lead to substantial improvements in cognition and reduced brain pathology.
Strategies for improving cognition with aging: insights from a longitudinal study of antioxidant and behavioral enrichment in canines. (2009) PMID 19714491 (review)
Here we review the results of an intervention study using a canine model of human aging. The study was unique in that it compared the effects of dietary antioxidant supplementation alone and in combination with behavioral enrichment.
We found that both interventions lead to improvements in cognitive ability in aged dogs; however, combining the treatments preserved cognition to a greater extent than either treatment alone.
Reproduce: canine_trial_search(trial_id="beagle-antioxidant-diet-behavioral-enrichment") in dog-geroscience-mcp; dataset canine-trial-registry.