Reproductive performance and gonad histopathology of female Nile tilapia (Oreochromis niloticus Linnaeus 1758) exposed to palm oil mill effluent

Palm oil mill effluent (POME) has potential to contaminate the aquatic environment. This paper investigated the reproductive performance and gonad histopathology of female Nile tilapia (Oreochromis niloticus Linnaeus 1758) exposed to POME. Specifically, it examined changes in important parameters of reproductive performance (gonadosomatic index, fecundity, and oocyte diameter) and gonad histopathology. A chronic test was carried out experimentally using a completely randomized design consisting of four treatments with three replicates: treatment control (0 mg/L), treatment A (1.565 mg/L), treatment B (2.347 mg/L), and treatment C (3.130 mg/L). Results indicated that the POME exposure had no significant impact on fecundity of Nile tilapia. Nevertheless, exposure to POME triggered a decline in gonadosomatic index and shrunk the oocyte diameter of Nile tilapia. The histopathology test confirmed that exposure to POME impacted on the occurrence of follicular atresia, disorientation of gonad form, chinion layer depletion and yolk granular degeneration.