Sunlight's healing effects help imperiled green sea turtles with tumors
Study examines use of UV rays to boost vitamin D Levels, promote healing
and prevent tumor regrowth

Date:
April 12, 2022
Source:
Florida Atlantic University
Summary:
Helping green sea turtles suffering with large debilitating tumors
may be a simple as sunlight. Turtles with fibropapillomatosis
are treated at rehab facilities where the tumors are surgically
removed. Many do not survive or the tumors regrow. Researchers
compared vitamin D levels in green sea turtles with and without
evident tumors to see if sunlight exposure would influence vitamin
D levels and other health parameters.

Turtles receiving treatment were housed in tanks exposed to higher
or lower levels of sunlight. Results showed that turtles exposed
to greater sunlight showed greater increases in plasma vitamin D
and a more successful recovery. Turtles kept in the sun tanks also
experienced less regrowth of tumors compared to those exposed to
low UV light conditions.



FULL STORY ==========================================================================
A new study by Florida Atlantic University researchers is literally
shedding "light" on a way to improve the health of endangered
green sea turtles (Chelonia mydas) prone to a disease called fibropapillomatosis. Affecting about 60 percent of sea turtles in
some sub-populations, juveniles are most susceptible to this disease
that causes the growth of large debilitating tumors on the skin, eyes
and shell.


========================================================================== Turtles with fibropapillomatosis are treated at rehabilitation facilities
where the tumors are surgically removed. Unfortunately, many of them do
not survive or the tumors regrow.

One solution to helping this population of sea turtles could be as simple
as sunlight. Many turtle rehabilitation facilities have enclosures that
limit sea turtles' exposure to natural ultraviolet (UV) light. Rays from
sun exposure are an important source of vitamin D, which is an essential nutrient in vertebrates that plays many physiological roles. Importantly,
sea turtles with fibropapillomatosis show reduced vitamin D levels and variations in blood chemistry parameters.

For the study, FAU researchers compared vitamin D levels in green sea
turtles with and without evident fibropapillomatosis to determine if
exposure to sunlight would influence vitamin D levels and other health parameters. They also examined differences between turtles brought in to rehabilitation facilities and healthy wild-caught juvenile green turtles.

In addition, researchers investigated if higher levels of sun exposure
increase vitamin D levels in sea turtles undergoing treatment for fibropapillomatosis compared to turtles receiving less ultraviolet
light. Since turtles both with and without visible tumors entered the rehabilitation facility, researchers also checked to see if there was
any correlation between sun exposure, vitamin D and tumor regrowth.

Turtles receiving treatment were housed in tanks exposed to higher or
lower levels of sunlight for up to six months. Researchers looked at
hematology and blood chemistry parameters and vitamin D, parathyroid
hormone (regulates calcium levels in the blood) and ionized calcium
levels. Turtles that had tumor removal surgery were monitored for any
regrowth.

Results of the study, published in the journal Animals,revealed that
turtles exposed to greater sunlight showed greater increases in plasma
vitamin D and a more successful recovery. Vitamin D levels increased over
time in turtles in rehabilitation with the most significant increases seen
when the turtles were exposed to higher levels of UV light and for longer times. Those turtles kept in the sun tanks experienced less regrowth of
tumors compared to those exposed to low UV light conditions. The results suggest that increasing sun exposure in rehabilitation facilities may
enhance health and recovery in green sea turtles with fibropapillomatosis.

Opon intake, tumored turtles had lower plasma vitamin D and ionized
calcium levels and higher parathyroid hormone levels when compared to
both wild-caught and rehabilitation turtles without evident tumors.

"Data from our study suggest that one potential method to better
the outcome of sea turtles with this disease is to increase their
exposure to UV light during rehabilitation," said Sarah L. Milton,
Ph.D., senior author, chair and professor, Department of Biological
Sciences, FAU Charles E. Schmidt College of Science, and a member of
the FAU Stiles-Nicholson Brain Institute and FAU Institute for Human
Health and Disease Intervention (I-Health). "Although a cure for this
disease has yet to be discovered, we have shown that exposure to higher
UV light increases vitamin D in turtles, as it does in other animals
including humans. Increased plasma vitamin D levels are then in turn
correlated with lower rates of disease. This potential to boost health
could therefore contribute to improved recovery. For future studies, we
would be interested to see if there are direct links between vitamin D
levels and immune function." Study co-author is Victoria E. Garefino, an
FAU graduate of Milton's laboratory. This research was funded by Friends
of Gumbo Limbo and National Save the Sea Turtle Foundation grants awarded
to Milton.


========================================================================== Story Source: Materials provided by Florida_Atlantic_University. Original written by Gisele Galoustian. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Victoria E. Garefino, Sarah L. Milton. Influence of Sunlight on
Vitamin D
and Health Status in Green (Chelonia mydas) Sea Turtles
with Fibropapillomatosis. Animals, 2022; 12 (4): 488 DOI:
10.3390/ani12040488 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220412095421.htm

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