The potential of graphene oxide as a new antibacterial agent in controlling motile aeromonad septicemia due to aeromonas hyrdophila for aquaculture uses.

• Main Author: Muhammad Mustaqim Md. Tujudin
• Format: UMK Etheses
• Language: English
• Published: 2017
• Subjects: Q Science (General)
• Online Access: http://discol.umk.edu.my/id/eprint/10251/1/MUHAMMAD%20MUSTAQIM%20BIN%20MD.%20TUJUDIN.pdf; http://discol.umk.edu.my/id/eprint/10251/

Aeromonas hydrophila is a common bacterium in fresh water fish that causes a disease known as Motile Aeromonad Septicemia (MAS). Nowadays, the development of aquaculture industry has led to the excessive usage of antibiotics to infected fish. Subsequently, antibiotic resistance case is increasing among pathogenic bacteria. New antibacterial agents need to be discovered to control the diseases outbreak in aquaculture. This study was conducted to evaluate the potential of Graphene Oxide (GO) as a new antibacterial agent in controlling Motile Aeromonad Septicemia (MAS) disease. In this study, A. hydrophila was isolated from diseased red hybrid tilapia in commercial aquaculture farm at Jeli, Kelantan. The bacteria were isolated on Glutamate Starch Phenol (GSP) agar and continued subculture into Tryptic Soy Agar (TSA) and blood agar. An identification of15 isolates bacterium was conducted by using biochemical test and commercial kit (BBL, USA). Minimum inhibitory concentration (MIC) of GO was evaluated by two-fold micro dilution method whereas erythromycin was used as a positive control. This research continued by in vivo test to investigate the efficacy of GO on the growth performance of juvenile red hybrid tilapia in terms of final body weight (FBW), percentage weight gain (PWG), specific growth rate (SGR) survival rate and relative percentage survival (RPS). Fish were randomly divided into six groups; one control group and five treated groups with five different concentrations of GO (GO-25; 0.25 mg/kg, GO-50; 0.5 mg/kg, GO-100; 1.0 mg/kg, GO-200; 2.0 mg/kg and GO-400; 4.0 mg/kg of fish). Each group was triplicated, which consists of 20 fish in each replicate. After a week fed with medicated feed at 2% body weight, all fish were injected with Aeromonas hydrophila at 1×109 CFU/kg of fish and coated feed was continuously fed to the fish for six weeks period. Fish antibody response was monitored by indirect enzyme- linked immunosorbent assay (ELISA). Results showed that minimum inhibitory concentration (MIC) value of GO against A. hydrophila was in between 250 µg/mL to 4000 µg/mL. The result of in vivo showed that control group showed significantly higher (p<0.05) in term of growth performance (FBW, PWG and SGR) that are 6.16 ± 0.06, 15.3 ± 1.69 and 2.01 ± 0.01 while the lowest body weight and weight gain showed by fish in GO-25 group. However, treated groups showed significantly higher survival rate compared to control group (p<0.05). Antibody response based on indirect ELISA also showed that fish fed with GO showed significantly higher immune response indicated by higher OD reading (p<0.05) and GO-200 (0.049 ± 0.01) showed the highest Relative Percentage Survival (RPS) among treated groups. This study successfully revealed the potential of GO not only as a new antibacterial agent but also immunostimulant agent against A. hydrophila especially fish in GO-200 group.