The impact of musk ketone on reproduction in zebrafish (Danio rerio)

Nitro musks are a group of nitrated benzenes mainly used by the fragrance industry as a substitute for natural musk. Two of the most common nitro musks, musk xylene and musk ketone, have been detected in water, fish, human adipose tissue, as well as in human breast milk. In this study, female zebrafish were dietary-exposed to musk ketone, prior to spawning with unexposed males. The fish were exposed for 8 weeks at two different dose levels. Accumulation of the compound in the fish as well as reproductive success were studied. Exposed females had reduced body weight and length, as well as reduced liver- and gonad somatic index. The results from the reproduction study showed a dose-dependent reduction in fecundity. Early life-stage mortality was increased and the median survival time was reduced. In addition, an embryo/larvae toxicity test was performed, using newly fertilized zebrafish eggs from unexposed parental fish. Eggs were exposed to a series of different concentrations of musk ketone via the surrounding water. A NOEC value of 10 micrograms/l and a LOEC value of 33 micrograms/l was determined. Conclusively, the present study clearly shows that musk ketone negatively affects reproduction and early life-stage survival in zebrafish.