Optimizing the design of a reproduction toxicity test with the pond snail Lymnaea stagnalis

Abstract

This paper presents the results from two ring-tests addressing the feasibility, robustness and reproducibility of a reproduction toxicity test with the freshwater gastropod Lymnaea stagnalis (RENILYS strain). Sixteen laboratories (from inexperienced to expert laboratories in mollusc testing) from nine countries participated in these ring-tests. Survival and reproduction were evaluated in L. stagnalis exposed to cadmium, tributyltin, prochloraz and trenbolone according to an OECD draft Test Guideline. In total, 49 datasets were analysed to assess the practicability of the proposed experimental protocol, and to estimate the between-laboratory reproducibility of toxicity endpoint values. The statistical analysis of count data (number of clutches or eggs per individual-day) leading to ECx estimation was specifically developed and automated through a free web-interface. Based on a complementary statistical analysis, the optimal test duration was established and the most sensitive and cost-effective reproduction toxicity endpoint was identified, to be used as the core endpoint. This validation process and the resulting optimized protocol were used to consolidate the OECD Test Guideline for the evaluation of reproductive effects of chemicals in L. stagnalis.

New Insights to Compare and Choose TKTD Models for Survival Based on an Interlaboratory Study for Lymnaea stagnalis Exposed to Cd

“…Prior to the tests, snails were sampled from a parasite-free cohort, checked for identical size (27 ± 2 mm), shell integrity and reproduction ability. 3,5 As regards Cd, from 5 to 7 concentrations per laboratory were tested, ranging from 16 to 486 μg•L −1 (average measured concentrations). The concentration, the temperature (20 °C ± 1 °C) and the dissolved oxygen concentration ([O 2 ] > air saturation value) were maintained constant over 56 days long, during which the reproduction and the mortality of snails were monitored twice a week.…”

“…9 In the present study, we revisited the data sets from the two ring-tests studied by Ducrot et al in 2014 3 and Charles et al in 2016. 5 These ring-tests were performed in the scope of the consolidation of the OECD Test Guideline for the assessment of chemical effects on Lymnaea stagnalis (the Great Pond Snail) reproduction. 3,5,6 The present study focused however only on the survival of this hermaphrodite freshwater snail when exposed to cadmium (Cd).…”

Pond Snail Reproduction as Model in the Environmental Risk Assessment: Reality and Doubts

“…This recommendation provides a guide with a five-level assessment but not indented to be a testing strategy of various EDCs. Another OECD reproductive toxicity test guideline with the pond snail L. stagnalis is also available from 2010 [25] and this optimized in 2016 using the steroidal TBT [30]. Several studies published data with different endpoints (number of egg mass, eggs, survival and shell size) recommended in OECD guidelines in progestogen exposure of L. stagnalis [23][24][25][26][27][28]116].…”

Diet quality affects chemical tolerance in the freshwater snail Lymnaea stagnalis

“…It is present in both fresh and brackish water and ingests plants, carrion, algae, and microorganisms (Gl€ oer et al 1992;Schwab 2002). The species is used for an OECD guideline toxicity test for exploring the reproductive effects of toxicants on freshwater molluscs (Organisation for Economic Co-operation and Development 2016; Charles et al 2016). Our laboratory culture was initiated with egg masses obtained in 2013 from a culture at the University of Miami (Coral Gables, FL, USA).…”