As sea creatures go, juvenile lumpfish are pretty cute.
Their adult counterparts? Not so much.
Regardless, the dull, lumpy bottom feeders with warty heads are not only an integral part of the provincial economy — their roe is prized in Asia as an alternative to caviar — they are also the subject of innovative research being done at Memorial that will assist both the aquaculture industry and provide insight into dietary effects on vision.
Dr. Robert Gendron, Department of Biomedical Science, Faculty of Medicine, has teamed up with Dr. William Driedzic, Department of Ocean Sciences, Faculty of Science, to study dietary vitamins in the vision health of lumpfish.
Their project recently received funding through Memorial University’s Vitamin Research Fund, which links to the Ocean Frontier Institute (OFI).
How did a professor of cancer and cardiovascular biology start collaborating with one Memorial’s leading marine bioscientists to study the effects of dietary vitamins on vision health?
“After we acquired new advanced retinal imaging instrumentation in 2016, we realized that we could conduct ophthalmologic research on ocean fish using the same equipment that we use on humans and that the results could be applicable to both,” said Dr. Gendron.
“Our first collaboration with Dr. Driedzic was to study the retinas of temperature-stressed rainbow smelt. We found they showed a very surprising natural regulation of the very same pathways that control retinal blood vessel permeability in humans.”
Monitoring vision health
That work provided insight into how certain disease-related processes might, in other settings, be very similar to natural stress responses.
“Just as rainbow smelt must adapt to temperature changes, lumpfish also must adapt to changes in their diet,” explained Dr. Gendron. “We realized that varying or restricted dietary vitamin A could be a significant stress to lumpfish.”
With this in mind, the research team will monitor the vision health of juvenile lumpfish retina using the same rapid high-resolution eye imaging equipment used in human ophthalmology clinics.
The new infrastructure was recently acquired by Drs. Gendron and Hélène Paradis, also of the Faculty of Medicine, through the Canada Foundation for Innovation.
The lumpfish, which are cultured entirely at Memorial’s Department of Ocean Sciences in Logy Bay, are perfect research subjects, says Dr. Gendron.
“Lumpfish need healthy vision to see and eat food, no matter whether that food is.”
Since the diet of cultured lumpfish is controlled, the researchers can study and even improve their diet, particularly vitamin A, and monitor any changes in retinal structure or function.
“The eyesight of lumpfish is important, because in addition to their commercial value in the province, they are now also beginning to be used as a means of de-licing aquaculture salmon,” Dr. Gendron said, adding that the better the fish see, the more useful they are to the aquaculture industry.
“Lumpfish need healthy vision to see and eat food, no matter whether that food is feed pellets, sea lice on salmon or other wild crustacea in our oceans.”
The research will provide new knowledge on the role of dietary vitamin A in the fitness of the lumpfish and will have direct impacts on the success of the aquaculture industry by providing a better understanding of how to optimize aquaculture diets.
The results of the lumpfish study may have broader implications since they could reveal novel knowledge about physiological and metabolic adaptation to regulate vitamin A metabolism in the face of environmental stress.
Such knowledge could be relevant to the study of other fish and mammals including humans, says Dr. Gendron.
“Since vitamin A metabolism is central to a range of human retinal diseases,” he said, “understanding how lumpfish might manage vitamin A metabolism in the face of stress could teach us a thing or two not only about basic lumpfish biology, but also about how to better understand how the human retina handles vitamin A during stress and disease.”
This project brings together expertise from the Department of Ocean Sciences (Danny Boyce, facility and business manager with the Dr. Joe Brown Aquatic Research Building) and the Faculty of Medicine (Dr. Hélène Paradis, professor of vascular molecular biology/pediatric cancers).
It will also involve the graduate training of Raahyma Ahmad, M.Sc. candidate, and Lidan Tao, expert technical assistance in mass spectrometry.