GB/T 35517-2017 in English

Analysis of the core content of the standard

This standard is equivalent to the OECD Test Guideline 229 (2012) to establish a 21-day short-term screening method for fish reproductive toxicity, which is used to detect the endocrine disrupting activity of chemicals. The test uses three model organisms, zebrafish, fathead minnow and medaka, to monitor key biomarkers such as vitellogenin (VTG) and changes in secondary sexual characteristics.

Key elements of experimental design

Core technical methods

1. Vitellogenin Determination

Sample Collection:Male fish blood/liver (medaka) or head and tail homogenate (zebrafish), see Appendix A for detailed operation. ELISA detection must meet the following requirements:

• Calibration curve R²>0.99
• Parallel sample difference ≤20%
• Spike recovery 70-120%

2. Secondary Sexual Characteristics Assessment

Suggestions for the implementation of the standard

1. Species selection:Give priority to the three types of fish recommended in the standard. Note that zebrafish have no quantifiable secondary sexual characteristics
2. Positive control:It is recommended to use 17β-estradiol (estrogen) and fadroxil (aromatase inhibitor) to verify laboratory capabilities
3. Data interpretation:A comprehensive analysis of multiple endpoints such as fertility and histopathology is required to avoid misjudgment of a single indicator

Technological evolution and background

This standard is based on the OECD validation study (2006-2008) to address the problems of long cycle and high cost of traditional fish life cycle testing. Capturing key endocrine disruption events through short-term exposure:

• VTG response: a sensitive indicator of estrogen/anti-androgen effects
• Secondary sexual characteristics: directly reflect androgen receptor activation
• Gonadal pathology: providing additional evidence for the mechanism of action