Arachidonic acid enhances reproduction in Daphnia magna and mitigates changes in sex ratios induced by pyriproxyfen. (21st January 2015)

• Record Type: Journal Article
• Authors: Ginjupalli, Gautam K.; Gerard, Patrick D.; Baldwin, William S.
• Is Part Of: Environmental toxicology and chemistry. Volume 34:Number 3(2015:Mar.)
• Page Start: 527
• Page End: 535
• Publication Date: 2015-01-21
• Subjects: Pollution -- Environmental aspects -- Periodicals; Environmental chemistry -- Periodicals; 615.902
• DOI: 10.1002/etc.2804
• Languages: English
• ISSNs: 0730-7268

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="etc2804-sec-0001" sec-type="section"> <p>Arachidonic acid is 1 of only 2 unsaturated fatty acids retained in the ovaries of crustaceans and an inhibitor of HR97g, a nuclear receptor expressed in adult ovaries. The authors hypothesized that, as a key fatty acid, arachidonic acid may be associated with reproduction and potentially environmental sex determination in <italic>Daphnia</italic>. Reproduction assays with arachidonic acid indicate that it alters female:male sex ratios by increasing female production. This reproductive effect only occurred during a restricted <italic>Pseudokirchneriella subcapitata</italic> diet. Next, the authors tested whether enriching a poorer algal diet (<italic>Chlorella vulgaris</italic>) with arachidonic acid enhances overall reproduction and sex ratios. Arachidonic acid enrichment of a <italic>C. vulgaris</italic> diet also enhances fecundity at 1.0 µM and 4.0 µM by 30% to 40% in the presence and absence of pyriproxyfen. This indicates that arachidonic acid is crucial in reproduction regardless of environmental sex determination. Furthermore, the data indicate that <italic>P. subcapitata</italic> may provide a threshold concentration of arachidonic acid needed for reproduction. Diet‐switch experiments from <italic>P. subcapitata</italic> to <italic>C. vulgaris</italic> mitigate some, but not all, of arachidonic acid's effects when compared with a <italic>C. vulgaris</italic>–only diet, suggesting that some arachidonic acid provided by <italic>P. subcapitata</italic> is retained. In summary, arachidonic acid supplementation increases reproduction and represses pyriproxyfen‐induced environmental sex determination in <italic>D. magna</italic> in restricted diets. A diet rich in arachidonic acid may provide protection from some reproductive toxicants such as the juvenile hormone agonist pyriproxyfen. <italic>Environ Toxicol Chem</italic> 2015;34:527–535. © 2014 SETAC</p> </sec> </abstract>