Growth, lipid
class and fatty acid composition in juvenile mud crabs (Rhithropanopeus
harrisii) following larval exposure to Fenoxycarb (R), insect juvenile
hormone analog
S.F. Nates, C.L. McKenney-2000
Comparative Biochemistry and Physiology – C:
Toxicology and Pharmacology, 127(3): 317-325
(from Current Contents)
Abstract :
This study examines the effects of Fenoxycarb(R) on
larval growth, and lipid class and fatty acid composition in first crabs of
the mud crab Rhithropanopeus harrisii reared through total larval
development in nominal water concentrations from 1 to 100 mug/l. In first
crabs of R. harrisii, dry weight (mug) decreased significantly (P < 0.05)
from 228.8 +/- 38.2 <mu>g (n = 9) in the controls to 131.8 +/- 10.1
mug (n = 4) in animals exposed throughout larval development to 100 mug/l. A
significant (P < 0.05) reduction was found between total lipid content in
the controls and first crabs reared at concentrations greater than 50
<mu>g/l. In relative terms (% dry weight), different lipid classes
predominated in the controls and the various fenoxycarb exposure
concentrations. There were no significant (P > 0.05) differences among
the treatment groups in phospholipid level, while the triglyceride content
was significantly lower in crabs exposed to 10 and 100 mug/l. No significant
differences in the percent of free fatty acids were found in crabs exposed
to 1-10 mug/l and the controls. Free sterols in crabs exposed to
concentrations higher than 10 mug/l were below the detection limit. Control
animal fatty acid profiles were dominated by palmitic, stearic, and oleic
acid, accounting for 48% of total fatty acids (TFA). The fatty acid
composition of crabs exposed to 100 mug/l significantly (P < 0.05)
differed from the controls. The results suggest that fenoxycarb has
substantial effects on growth, lipid class and fatty acid composition in
developing larvae of R. harrisii at water concentrations greater than 10
<mu>g/l.
(US EPA, Natl Hlth & Environm Effects Res Lab, 1
Sabine Island Dr, Gulf Breeze, FL 32561, USA, e-mail : nates.sergio@epa.gov)