When we think of fish oil supplementation for pets we generally think about the older cats and dogs. My last blog focused on the use of fish oil in older cats to alleviate the discomfort of osteoarthritis. Few veterinarians recommend fish oil for younger patients and few commercial pet foods for younger animals are fortified with fish oil. But new research suggests that puppies may benefit from DHA-rich fish oil.
The Fish Oil Study
A group of 48 weaned Beagle puppies were divided into 3 groups at 8 weeks of age. Each group received a diet that was low in fish oil, moderate in fish oil, or high in fish oil until 52 weeks of age. During this growth period, the groups of puppies were periodically evaluated for cognitive learning, memory, psychomotor, and eye retinal function. The puppies’ immune response to rabies vaccination was also evaluated.
Elaborate maze, object discrimination and displacement, visual contrast discrimination, and landmark discrimination protocols were administered to the puppies at various ages and stages of neurological development. These testing protocols measure learning function of the brain. A memory test protocol was performed by all of the puppies between 33 and 44 weeks of age. Psychomotor skills were evaluated at 3, 6 and 12 months of age by timing the ability to navigate an obstacle filled maze.
Electroretinography examinations were performed on the puppies at 4, 6 and 12 months of age to measure the visual activity of the retina of the eye. Puppies were periodically blood tested to confirm that the amounts of DHA in the blood corresponded to the levels of fish oil fed.
Findings of the Fish Oil Study
The researchers found that with the exception of sight contrast discrimination, cognitive learning did not significantly differ among the groups. Psychomotor skills did not differ with fish oil treatments. However, retinal function was significantly improved with high levels of fish oil.
Interestingly, high fish oil puppies had a much higher anti-rabies antibody in their blood 1 and 2 weeks after their vaccination. The researchers concluded that since visual contrast discrimination and retinal activity correlated with blood levels of DHA, fish oil may aid in the neurological development of puppies.
Focus on DHA
The essential fatty acid DHA (docasahexaenoic acid) is a cell structure component of primarily brain and nerve cells. It is also found in the cell structure of skin, sperm, and retina of the eye. It is also used as a part of the treatment protocol for many types of cancer. Fish oil is rich in DHA. Krill oil is even richer in DHA. Krill are tiny ocean crustaceans or shellfish that are eaten by fish and some marine mammals. Krill obtain their DHA from the sea algae that comprise their entire diet. More recently available are powders made from dried algae grown under special conditions, which are even richer sources of DHA.
As noted in my last blog, the National Research Council (NRC) has established a safe upper limit for DHA and EPA (eicosapentaenoic acid) combined. The safe upper limit for DHA alone is not defined. Consult your veterinarian for the appropriate dosages of the various sources of DHA needed for your puppies.
Visual and retinal function is much different in the cat than in the dog. DHA supplementation in kittens may not have the same beneficial visual or neurological development effects. Until there is more research in this area, my personal and professional opinion is that fish oil supplementation in kittens is safe so all risk is to the positive upside. Again, consult your veterinarian for the proper dosing for your kitten.
Dr. Ken Tudor