The disruptive effect of mercury chloride (HgCl) on gene expression of gonadotrophin hormones and testosterone level in male silver sharkminnow (Osteochilus hasseltii C.V.) (Teleostei: Cyprinidae)

Abstract

Endocrine-disrupting compounds in water affect reproductive activities in fish. Mercury is a toxic and persistent pollutant, which bioaccumulates in the food chain. To investigate the effect of mercury chloride (HgCl) on fish reproduction, animals were kept in four aquaria containing increasing levels of HgCl (0 mg/L [control]; 0.025 mg/L [low]; 0.05 mg/L [medium]; 0.1 mg/L [high]) for 60 days. The effects of HgCl on reproduction performance of male silver sharkminnow were evaluated by GtH-Ia, GtH-IIa and GtH-IIb gene expression, testosterone levels, and GSI levels. A significant decrease in Gonadothropin Hormone type I sub unit alpha (GtH-Ia), Gonadothropin Hormone type II sub unit alpha (GtH-IIa) and Gonadothropin Hormone type II sub unit beta (GtH-IIb) gene expression, testosterone levels, and Gonado Somatic Index (GSI) levels was detected in fish receiving the high mercury dose compared to controls after 2, 4, 6 and 8 weeks (P < 0.05). After 4, 6 and 8 weeks, all treatment groups had significantly lower GtH-Ia, GtH-IIa and GtH-IIb gene expression, testosterone levels and GSI levels compared to the control group (P < 0.05). These findings demonstrate a disruptive role of mercury on reproductive performance in male silver sharkminnow.

The Effect of Endosulfan in GnRH and GtH Genes Expression of Male Hard-Lipped Barb (Osteochilus vittatus C.V.)

“…Hence, the endosulfan treatment has not had a significant effect on the fluctuation in the expression of the GtH-II gene. This is consistent with the results of the research conducted by Siregar and Prayogo (2017), which reported that exposure of the fish to mercury chloride (HgCl) had no significant influence on the expression of its GtH-IIß gene. According to Taufik, Supriyono & Nirmala, (2009), as well as Taufik and Setiadi (2012), the lowest concentration of endosulfan exposure in carp was 1.4 μg /L.…”

“…This is because the time of endosulfan exposure had a major influence on the fluctuations in decreased GtH-II gene expression at this stage. These results are consistent with the research of Siregar and Prayogo (2017), which showed that exposure to mercury chloride (HgCl) had no significant effect on the expression of GtH-II gene between the control and treatment groups in male hard-lipped barb fish at the 4th week. In addition, the concentration of endosulfan treatment used for sublethal toxicity tests was classified as low at 15, 30 and 45% of the LC50-96 hour value, while the standard treatment concentration used for the sublethal toxicity test was 20, 40 and 60% of the LC50-96 hour value (Ansari & Ansari, 2014).…”

Sublethal Toxicity Tests of Mercury (Hg) to Nilem Fish (Osteochilus hasselti) Gills Tissue Damage

“…This is because at these E3S Web of Conferences 47, 04001 (2018) https://doi.org/10.1051/e3sconf/20184704001 SCiFiMaS 2018 concentrations, nilem fish not releasing much mucus out of mucus cells that can lead to increased lamella fusion. This is supported by a statement from Mulyani et al [13] that lamela fusion can occur because the mucus cells in the lamella are increased in number resulting in the fusion between the secondary lamella. Other damage to the gills of nilem fish is necrosis.…”

Mercury Exposure and Toxicological Consequences in Fish and Fish‐Eating Wildlife from Anthropogenic Activity in Latin America

“…When Au is extracted through amalgamation, most Hg is lost to the atmosphere as vapor, and the remainder drains directly into streams and rivers. Mercury vapor is toxic to Au miners and local residents (da Silva et al 2012; Siregar and Prayogo 2017). Inorganic Hg (IHg) that enters the aquatic environment, via wet or dry deposition, can then be methylated by microbial activity in sediments and converted to methylmercury (MeHg), increasing its bioavailability, toxicity, and biomagnification potential (Wiener et al 2003).…”