Plasma Retinol, Iron, and Thyroxine Concentrations as Indicators of Health in California Sea Lions (Zalophus californianus)
B. Fenwick1; R. Delong2; E. Norkus3; T.
Reidarson4
Plasma concentrations of retinol, triiodothyronine, thyroxine, and iron were
measured in captive adult California sea lions, as well as premature and full term free-living
California sea lion pups and their mothers.
Plasma retinol concentrations were significantly lower (P = 0.0006) in
premature pups than full term pups. In the same fashion, the mothers of the premature pups had
significantly lower retinol concentrations than the mothers of the full term pups. Plasma iron
concentrations of the premature pups were significantly higher (P < 0.05) than any of other
groups of sea lions, and the captive adult sea lions had higher plasma iron than the wild adult
sea lions. Differences in plasma triiodothyronine or thyroxin concentrations were not detected
between these groups of sea lions.
Retinol, triiodothyronine, thyroxine, and iron are important indicators of
heath and should be included in all medical evaluation of captive as well as free ranging marine
mammals.