Impact of di-n-butyl phthalate on reproductive system development in European pikeperch (Sander lucioperca)

Phthalic acid, di-n-butyl ester known as di-n-butyl phthalate, is an organic chemical compound that belongs to the group of endocrine disruptor compounds that have a documented negative impact on mammalian endocrine systems. Di-n-butyl phthalate is used widely as a plasticizer in the manufacture of artificial materials, which is why it is found in all types of environmental samples including those from water basins. The aim of the study was to describe the impact of di-n-butyl phthalate on the development of the reproductive system of European pikeperch (Sander lucioperca) during the sex differentiation period (age 61–96 days post hatch). A total of 240 fish were divided into 6 groups (40 fish per tank). Treatments consisted of a control group (0 g di-n-butyl phthalate/kg feed) and five trial groups with 0.125, 0.25, 0.5, 1, and 2 g di-n-butyl phthalate/kg feed, resp. Histological changes of the fish gonads, sex ratio, survival and growth of fish were evaluated. Di-n-butyl phthalate seriously disturbed sex differentiation process of pikeperch. Histopathological analyses revealed that the administration of 2 g di-n-butyl phthalate/kg significantly affected the sex ratio. The feminization process (intersex gonads) at concentrations of 1 g and 2 g di-n-butyl phthalate/kg were observed. All analyzed concentrations delayed testicular development. Phthalate did not have a significant impact on the survival or growth rates of the pikeperch. This is the first report of disruption sex differentiation processes in fish by di-n-butyl phthalate.