Hazard evaluation of diisononyl phthalate and diisodecyl phthalate in a Japanese medaka multigenerational assay

• Published in: Ecotoxicology and environmental safety 2006-09, Vol.65 (1), p.36-47
• Main Authors: Patyna, P.J., Brown, R.P., Davi, R.A., Letinski, D.J., Thomas, P.E., Cooper, K.R., Parkerton, T.F.
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Body Weight - drug effects; Cytochrome P-450 CYP1A1 - metabolism; Development; Diet; Ecotoxicology, biological effects of pollution; Embryo, Nonmammalian - drug effects; Embryo, Nonmammalian - embryology; Evaluation Studies as Topic; Female; Freshwater; Fundamental and applied biological sciences. Psychology; General aspects; Gonads - drug effects; Hazardous Substances - toxicity; Japanese medaka; Male; Organ Size - drug effects; Oryzias - metabolism; Oryzias latipes; Ovum - drug effects; Phthalate esters; Phthalic Acids - toxicity; Reproduction; Survival Analysis; Testosterone - metabolism; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2005.05.023

Reproductive and developmental effects of diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) were evaluated in a Japanese medaka ( Oryzias latipes) multigeneration protocol. Each phthalate was administered via fish flake diets at a concentration of 20 μg/g (1 μg/g fish/day). Two controls were included, untreated and acetone carrier. The F 0 and F 1 generation adults were reared to sexual maturation and the test was ended prior to sexual maturation of the F 2 generation. Biochemical, individual, and population parameters were evaluated: testosterone metabolism, 7-ethoxyresorufin- o-deethylase (EROD) activity, survival, development, growth, gonadal–somatic index, histopathology, sex ratio, and fecundity. Male fish showed a two-fold induction of several testosterone metabolites in the DINP-treated group compared to the untreated control but not the acetone control. In a similar manner, in female fish only the DIDP-treated group expressed greater testosterone hydroxylase activity. There were neither sex- nor treatment-related differences in the results from the EROD assay. A statistically significant transient delay in red blood cell pigmentation was observed. The male-to-female ratio was consistent across treatments and the phenotypic and histological gender classifications were in agreement. Egg production was not significantly different among treatment groups. Neither phthalate elicited an effect on reproduction or development at various levels of biological organization.