The oil-rich alga Schizochytrium sp. as a dietary source of docosahexaenoic acid improves shape discrimination learning associated with visual processing in a canine model of senescence.

Whole cell Schizochytrium sp. is a rich source of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) including docosahexaenoic acid (DHA), an important nutrient for brain health. Aged beagle dogs experienced on a visuospatial task of working memory, variable-delay delayed-non-matching-to-position were used to assess efficacy of DHA-rich microalgae based upon DHA wt% of total phospholipids and 8-iso-PGF2α concentrations in plasma, and performance on cognitive assessments of visual object discrimination, learning, and memory consolidation after 25 weeks on fortified diet. Improved DHA status (p<0.001) and initial learning of the protocols for visual and variable contrast discrimination (p<0.05), but not long-term recall of the concurrent discrimination task were observed in animals fed the algal-fortified diet. Overall, results were consistent with dried Schizochytrium sp. as a source of n-3 LCPUFA nutrition to support DHA status in large mammals, and healthy brain function in a canine model of senescence.