LAUSR

Abstract Edwardsiellosis is a serious septicemic bacterial disease that induces high mortality in fish of economic value such as Clarias gariepinus (C. gariepinus). Nanotechnology has become a modern indispensable tool for use in preventing and treating of fish diseases. Moreover, nanomaterials have the potential for prevention and treatment of fish diseases. The current study was aimed to evaluate the role of ginger (GN) and its nanoparticles (GNNPs) in Edwardsiellosis prevention in C. gariepinus after in-vitro determination of these natural products. Experimental infection, determination of the median lethal dose (LD50) of Edwardsiella tarda (E. tarda) and histopathological examinations were performed. GN and GNNPs synthesized by ball milling were characterized by Fourier transform infrared spectroscopy (FTIR), zeta potential, hydrodynamic particle size, scanning electron microscopy (SEM) and X-ray differentiation analysis (XRD). GNNPs had less negative surface charge and lower particle and hydrodynamic size distribution than bulk ginger. Also, the functional groups on the surface of GN particles were not affected by the milling process. GNNPs had higher antibacterial activity against E. tarda than GN. Experimentally infected C. gariepinus showed skin haemorrhagic ulcerations with a foul odor, loss of skin coloration and fins disintegration. The LD50 was 1.5 × 104 colony forming unit, CFU/ml. GNNPs succeeded in preventing Edwardsiellosis in dietary fed C. gariepinus with no mortality compared to 10% and 70% in group of C. gariepinus fed traditional GN and the positive control group, respectively. Dietary GNNPs induced a non-significant effect on liver functions with a slight increase in serum urea. These enzymes were significantly elevated in the positive control group. Regarding the histopathological findings, the positive control group showed severe histopathological lesions compared to the negative control group. Normal and mild histopathological alternations were observed in the groups fed GNNPs and GN then injected with E. tarda, respectively.