Performance of mycelial biomass and exopolysaccharide from Malaysian Ganoderma lucidum for the fungivore red hybrid Tilapia (Oreochromis sp.) in Zebrafish embryo

Natural mycelial biomass (MB) and extracted exopolysaccharide (EPS) from the pre-grown Malaysian Ganoderma lucidum mushroom are both considered as high-end materials due to their high commercial value in the aquaculture industry. To evaluate their potential toxicity as a fish-feed supplement for the fungivore red hybrid Tilapia (Oreochromis sp.), both MB (250-5000 mu g/mL) and EPS (62.5-3000 mu g/mL) were subjected to zebrafish embryo toxicity (ZFET) assay, and the effects on zebrafish embryos (ZE) early development were analyzed between 24-120 hours of post-exposure (HPE). MB and EPS showed no toxic effect towards the ZE with LC50 of 1650 mu g/mL and 2648.38 mu g/mL, respectively. MB at concentrations between 250-5000 mu g/mL and EPS at 3000 mu g/mL showed no significant changes in ZE hatching. No significant changes in the ZE heart rate were detected following treatment with both tested compounds (MB: 250-2000 mu g/mL and EPS: 62.5-3000 mu g/mL) as compared to untreated embryos (135.5 beats/min). Furthermore, teratogenic effects of both MB and EPS (< 3000 mu g/mL) on zebrafish embryonic development were not observed. Together, both natural compounds MB and EPS can be considered non-toxic, suggesting that these can be safely applied as feed substances in the fish-feed aquaculture industry.