Assessing the recovery of steroid levels and gonadal histopathology of tilapia exposed to polystyrene particle pollution by supplementary feed

Abstract

Background and Aim: Water pollution caused by industrial waste and human activities has disrupted the reproductive health of aquatic organisms. This study aimed to analyze the effects of water pollution caused by polystyrene particles (PP) on the steroid (estradiol and testosterone) levels and histopathology of male tilapia gonads. In addition, we also analyzed the potential of supplementary feeding to remove and neutralize oxidants. Materials and Methods: Thirty-six tilapia fishes were taken for the study and were divided into 12 groups (n=3), including a control group (fed with commercial pellets only) and groups fed with a mixture of commercial-probiotic pellets (200 mL/kg, 1×108 colony-forming unit [CFU]/mL) and commercial vitamin C pellets (100 mg/kg), respectively. The PP concentrations used for this study were 0, 0.1, 1, and 10 mg/L, and the treatment time was 2 weeks. The testosterone and estradiol concentrations were analyzed by enzyme-linked immunosorbent assay and histopathological analysis of the gonads. Results: Laboratory analysis performed using tilapia fishes showed that exposure to a PP concentration of <74 μm, mixed with feed for 14 days, could decrease estradiol and testosterone levels. Exposure to plastic particles could change the structure, shape, and size of male gonads. It can also affect the spermatogenic cell number and alter the diameter inside the cysts. Originally, plastic particles were believed to reduce the permeability of the cyst membrane, and this damages the membrane or ruptures the cyst. Supplementary feed containing probiotics (200 mL/kg, 1×108 CFU/mL) and vitamin C (100 mg/kg) can ameliorate the impact of PP exposure on steroid levels. The steroid levels increase with a concurrent improvement in cysts and seminiferous tubule structures. Conclusion: Overall, this study indicates that PP concentrations in the aquatic environment negatively affect tilapia reproduction, and this may pose a potential threat to the fish population in freshwater. Provision of supplementary feed containing probiotics and vitamin C may serve as an alternative way to counter the negative impact caused by plastic particles.

Keywords

• fish
• fisheries
• freshwater
• polystyrene
• probiotics
• testicular