Effects of multi-well plate incubation on embryo-larval development in the Fathead minnow (Pimephales promelas)

Fathead minnow (Pimephales promelas) embryos and larvae are frequently used in toxicology, including short-term embryo-only tests which often use small volumes of test solution. The effect that such conditions may have on Fathead minnow development has yet to be explicitly described. Here we compared rates of embryonic development in Fathead minnow embryos reared under standard light and temperature conditions with a range of possible methods. All methods yielded excellent control survival. We demonstrated that Fathead minnow embryos incubated in a range of small volumes in multi-well plates [500 microlitres (μL) to 2 millilitres (mL) per embryo] did not substantially vary in developmental rate, but flexed less frequently as embryos, hatched smaller, later and with larger yolk-sacs, and initiated feeding later than embryos reared in an excess of solution (20 mL per embryo) with or without supplemental aeration. Faster hatch and growth were promoted with an orbital shaker, but growth benefits were not sustained into the larval stage. Developmental differences persisted in larvae reared to 20 days post-fertilization when monitoring ceased, but growth differences did not magnify and in some measurements partially resolved. To our knowledge we are the first to report effects of incubation in multi-well plates in any fish taxa. As our data revealed that the eleutheroembryonic stage for Fathead minnow may be prolonged in multi-well plates, this may allow the use of longer toxicity tests using Fathead minnow embryos without conflicting with existing animal welfare legislation in many countries.

The data file presents the individual length and weight to each Fathead minnow fry at hatch.

Supplemental Information

The Chemicals Management Plan (CMP) is a Government of Canada initiative aimed at reducing the risks posed by chemicals to Canadians and their environment. A key element of the Chemicals Management Plan is the monitoring and surveillance of levels of harmful chemicals in Canadians and their environment. Monitoring and surveillance are essential to identify and track exposure to hazards in the environment and associated health implications. Monitoring and surveillance programs provide the basis for making sound and effective public health and environmental health policies and interventions, as well as measuring the efficacy of control measures.

In support of the Chemicals Management Plan, monitoring and surveillance initiatives were established to support Health Canada and Environment and Climate Change Canada scientists, in collaboration with external partners and researchers, to advance our knowledge. This initiative has allowed the Government of Canada to increase its commitment to a number of existing monitoring initiatives, as well as to support new efforts.

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