Fig. 5

Fig. 5

a Occurrence of the endpoint “small eyes” in zebrafish (Danio rerio) embryos exposed for 120 h to valproic acid and selected analogues. Data are given as % of affected embryos (n = 20–40). Due to the low occurrence of < 10% of effects at the highest test concentration and software limitations, the EC₁₀ values computed for 2-propylheptanoic acid, valproic acid, 2-ethylbutyric acid and 2-ethylhexanoic acid were greater than the highest concentration tested in the FETs. Whereas embryos exposed to 2-propylheptanoic acid, 4-ene valproic acid, 2,2-dimethylvaleric acid, valproic acid, 2-etyhlbutyric acid and 2-ethylhexanoic acid showed an increase in the number of individuals with decreased eye size, embryos exposed to 2-methylpentanoic acid, 2-methylhexanoic acid, 4-pentenoic acid and hexanoic acid did not show an effect. b (a) Normal development of eyes in 120 h old zebrafish (Danio rerio) embryos. (b) Endpoint "small eyes" in 120 h old zebrafish embryos after treatment with 100 µM 2-n-propylheptanoic acid. Area of interest outlined in red