Effects of palm oil mill effluent on reproductive hormone of female Nile Tilapia, Oreochromis niloticus (Linnaeus 1758)

Abstract

Exposure to Palm Oil Mill Effluent has led to a disturbance on fish health, especially in reproduction. However, information related to the negative effect of Palm Oil Mill Effluent on fish reproduction performance is still rare. We aimed at investigating the reproductive hormone performances (estradiol, testosterone and progesterone) of female Nile Tilapia (Oreochromis niloticus Linnaeus 1758) exposed to Palm Oil Mill Effluent. A chronic test was carried out by using a completely randomized design consisting of four treatments including five replicates: control (0 mg/L), treatment A (1.565 mg/L), treatment B (2.347 mg/L), and treatment C (3.130 mg/L). Exposure to Palm Oil Mill Effluent triggered a significant decrease in estradiol and testosterone hormone (P < 0.05) but such a significant decrease was not observed in progesterone hormone (P > 0.05). Estradiol hormone decreased significantly from 4.42 ± 1.92 ng/mL in control to 1.35 ± 0.03 ng/mL in treatment C, while testosterone hormone decreased significantly from 6.63 ± 2.62 ng/mL in control to 1.18 ± 0.11 ng/mL in the treatment C. The significant decreasing of total lipid content in gonads also observed in treatment C. The disruption of synthesis of lipid can also be indicated from the elevated values of relative bile volume exposed to Palm Oil Mill Effluent.