Key Event Title
|Level of Biological Organization|
Key Event Components
Key Event Overview
AOPs Including This Key Event
|AOP Name||Role of event in AOP|
|Estrogen receptor agonism leading to reproductive dysfunction||KeyEvent|
|Aromatase inhibition leading to reproductive dysfunction||KeyEvent|
|Androgen receptor agonism leading to reproductive dysfunction||KeyEvent|
|Estrogen receptor antagonism leading to reproductive dysfunction||KeyEvent|
|Prolyl hydroxylase inhibition||AdverseOutcome|
|Unknown MIE leading to reprodl||AdverseOutcome|
|fathead minnow||Pimephales promelas||High||NCBI|
|Fundulus heteroclitus||Fundulus heteroclitus||High||NCBI|
|Oryzias latipes||Oryzias latipes||High||NCBI|
|Adult, reproductively mature||High|
Key Event Description
Spawning refers to the release of eggs. Cumulative fecundity refers to the total number of eggs deposited by a female, or group of females over a specified period of time.
How It Is Measured or Detected
In laboratory-based reproduction assays (e.g., OECD Test No. 229; OECD Test No. 240), spawning and cumulative fecundity can be directly measured through daily observation of egg deposition and egg counts.
In some cases, fecundity may be estimated based on gonado-somatic index (OECD 2008).
Domain of Applicability
Cumulative fecundity and spawning can, in theory, be evaluated for any egg laying animal.
Regulatory Significance of the Adverse Outcome
Cumulative fecundity is the most apical endpoint considered in the OECD 229 Fish Short Term Reproduction Assay. The OECD 229 assay serves as screening assay for endocrine disruption and associated reproductive impairment (OECD 2012). Fecundity is also an important apical endpoint in the Medaka Extended One Generation Reproduction Test (MEOGRT; OECD Test Guideline 240; OECD 2015).
A variety of fish life cycle tests also include cumulative fecundity as an endpoint (OECD 2008).
- OECD 2008. Series on testing and assessment, Number 95. Detailed Review Paper on Fish Life-cycle Tests. OECD Publishing, Paris. ENV/JM/MONO(2008)22.
- OECD (2015), Test No. 240: Medaka Extended One Generation Reproduction Test (MEOGRT), OECD Publishing, Paris.
- OECD. 2012a. Test no. 229: Fish short term reproduction assay. Paris, France:Organization for Economic Cooperation and Development.