Acclimating to toxicant stress is energy expensive. In laboratory toxicology tests dietary conditions are ideal, but not in natural environments where nutrient resources vary in quality and quantity. We compared the effects of additional
lipid resources,
docosahexaenoic acid (n-3; DHA) or
linoleic acid (n-6; LA), or the effects of the toxicants,
atrazine or
triclosan on post-treatment
starvation survival, reproduction, and
lipid profiles. Chemical exposure prior to
starvation had chemical-specific effects as DHA showed moderately beneficial effects on
starvation survival and all of the other chemicals showed adverse effects on either survival or reproduction. Surprisingly, pre-exposure to
triclosan inhibits adult maturation and in turn completely blocks reproduction during the
starvation phase. The two HR96 activators tested,
atrazine and LA adversely reduce post-reproduction survival 70% during
starvation and in turn show poor fecundity. DHA and LA show distinctly different
lipid profiles as DHA primarily increases the percentage of large (>37
carbon)
phosphatidylcholine (PC) species and LA primarily increases the percentage of smaller (<37
carbon) PC species. The toxicants
atrazine and
triclosan moderately perturb a large number of different
phospholipids including several
phosphatidylethanolamine species. Some of these polar
lipid species may be
biomarkers for diets rich in specific
fatty acids or toxicant classes. Overall our data demonstrates that toxicants can perturb
lipid utilization and storage in daphnids in a chemical specific manner, and different chemicals can produce distinct polar
lipid profiles. In summary,
biological effects caused by
fatty acids and toxicants are associated with changes in the production and use of
lipids.