Simvastatin enhanced growth and altered testis transcriptome profiles of male tilapias

Simvastatin (SIM), a commonly prescribed drug for lowering serum-lipid, has been detected in many aquatic environments. Exposure to high concentrations of SIM in rats and aquatic organisms resulted in toxicity to hepatocytes and negative effects on development. However, there is a paucity of studies on the effects of long-term exposure to low concentrations of SIM on aquaculture species. This study aimed to analyze the effects of environmentally relevant concentrations (0.1 μg/L and 1 μg/L) of SIM exposure for two months on developing Mozambique tilapias. Surprisingly, the growth of male tilapias was enhanced after a 2-month SIM exposure. The analysis of testis histology revealed that after the SIM exposure, the development of the testis was delayed, and sperm production was reduced. Sequencing of testis transcriptomes showed that the exposure to SIM altered the expression of many genes related to the development of testes and spermatogenesis. These data suggest that a 2-month exposure to environmentally relevant concentrations of increases the growth of male tilapias by inhibiting sexual development of males.