Growth, lipid
class and fatty acid composition in juvenile mud crabs (Rhithropanopeus
harrisii) following larval exposure to Fenoxycarb®, insect juvenile hormone
analog
S.F. Nates, Ch.L. McKenney Jr-2000
Comparative Biochemistry and Physiology - Part C:
Pharmacology, Toxicology and Endocrinology, 127 (3): 317 - 325
Abstract:
This study examines the effects of Fenoxycarb® 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 µg/l. In first
crabs of R. harrisii, dry weight (µg) decreased significantly (P<0.05)
from 228.8±38.2 µg (n=9) in the controls to 131.8±10.1 µg (n=4) in
animals exposed throughout larval development to 100 µg/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 µg/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 µg/l. No significant differences in the
percent of free fatty acids were found in crabs exposed to 1-10 µg/l and
the controls. Free sterols in crabs exposed to concentrations higher than 10
µg/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
µg/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 µg/l.
(U.S. Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Gulf Ecology Division,
One Sabine Island Drive, Gulf Breeze, FL 32561-5299, USA, Tel.:
+1-850-9342478; fax: +1-850-9342402, e-mail: nates.sergio@epa.gov)
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