Incubation at 32.5°C and above causes malformations in the zebrafish embryo.

Reproductive toxicology (Elmsford, N.Y.)

PubMedID: 26005098

Pype C, Verbueken E, Saad MA, Casteleyn CR, Van Ginneken CJ, Knapen D, Van Cruchten SJ. Incubation at 32.5°C and above causes malformations in the zebrafish embryo. Reprod Toxicol. 2015;.
Zebrafish embryos are increasingly used for developmental toxicity screening of candidate drugs and are occasionally co-incubated with a metabolic activation system at 32°C for 1, 2 or 4h, depending on their developmental stage. As this temperature is higher than the optimal temperature for zebrafish embryonic development (26-28. 5°C), we investigated whether continuous incubation of zebrafish embryos from 2. 5 until 96h post fertilization (hpf) at high temperatures (30. 5-36. 5°C) causes malformations. At 32. 5°C tail malformations were observed as early as 24hpf, and these became even more prominent at 34. 5 and 36. 5°C. Cardiovascular and head malformations, edema and blood accumulations throughout the body were present at 36. 5°C. Finally, temperatures higher than 28. 5°C accelerated embryonic development except for 36. 5°C, at which a lower hatching rate and hatching enzyme activity were observed. In conclusion, incubation of zebrafish embryos at 32. 5°C and above from 2. 5 until 96hpf causes malformations as early as 24hpf.