Crude oil contamination has been shown to impair reproduction in aquatic animals through carcinogenic and genotoxic properties. Here, we assessed the endocrine-disrupting function of crude oil on male reproductive system based on testicular histology, sex steroid hormones, and fertility endpoints in adult male goldfish (Carassius auratus), which were exposed to 0.02- to 2-mg/L crude oil for 21 days (Experiment #1) or to 5- to 250-mg/L crude oil for 9 days (Experiment #2). The crude oil contained 0.22-mg/L nickel (Ni), 1.10-mg/L vanadium (V), and 12.87-mg/L polycyclic aromatic hydrocarbons (PAHs). Twenty-four hours after adding crude oil, the sum of PAHs ranged from 0.30 to 2.28 μg/L in the aquaria containing 0.02- and 250-mg/L crude oil, respectively. Water analyses for heavy metals in Experiment #2 showed high concentrations (mg/L) of Ni (0.07-0-09) and V (0.10-0.21). For both experiments, exposure to crude oil did not impact gonadosomatic index; however, testes showed histopathological defects including hyperplasia or hypertrophy of Sertoli cells, depletion of the Leydig cells, necrosis of germ cells, and fibrosis of lobular wall. In Experiment #1, sperm production and motility, testosterone (T), and 17β-estradiol (E2) were not significantly different among treatments. In Experiment #2, the number of spermiating males decreased by ~50% following exposure to 250-mg/L crude oil. Sperm production, motility kinematics, T, and the T/E2 ratio significantly decreased in males exposed to ≥ 50-mg/L crude oil; however, E2 remained unchanged. Results show crude oil-induced imbalance of sex steroid hormones disrupts spermatogenesis resulting in diminished sperm production and motility.

Department of Fisheries Gorgan University of Agricultural Sciences and Natural Resources Gorgan Iran

Gas Research Division Research Institute of Petroleum Industry Tehran Iran

School of Biology College of Science University of Tehran Tehran Iran

School of Chemistry College of Science University of Tehran Tehran Iran

School of Fisheries Aquaculture and Aquatic Sciences Auburn University Auburn Alabama USA

South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses Faculty of Fisheries and Protection of Waters University of South Bohemia in České Budějovice Vodňany Czech Republic

South of Iran Aquaculture Research Centre Iranian Fisheries Science Research Institute Agricultural Research Education and Extension Organization Ahwaz Iran

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