Pakistan Journal of Biological Sciences -

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Simultaneous Administration of Boesenbergia pandurata Extract and Vaccination to Stimulate Immune Response in Tilapia, Oreochromis niloticus Posted: Background and Objective: The use of adjuvants or immunostimulants is often necessary to increase vaccine efficacy, in this study we evaluated the improvement of the immune response in tilapia treated by either oral and immersion administration with vaccine and Boesenbergia pandurata extract (BPE). Materials and Methods: The initial concentration of BPE and the cell density of vaccine were 900 mg L–1 and 104 CFU mL–1 for oral administration while 106 CFU mL–1 for immersion, respectively. The extract and vaccine were mixed homogeneously in a ratio of 1:1. Further, the mixture was supplemented to feed at 1 mL g–1 feed. Tilapia with average initial body weight of 15 g were fed containing vaccine and BPE 3 times a day. The other group of fish was immersed with vaccine and BPE for 20 min. After 7th (d7), 14th (d14) and21th (d21) days of treatment, a challenge test was conducted by intramuscularly injection of 0.1 mL of Aeromonas hydrophila and Pseudomonas fluorescens mixture (1:1) at a density of 105 CFU mL–1. Antibody levels, total white blood cell (WBC) and phagocytic activity (PA) were evaluated to determine the immune improvement of the fish. Furthermore, relative percent survival (RPS) and the survival rate (SR) were evaluated at week 2 and 4 after challenge test. Result: Results indicated that the all parameters of tilapia immune system were increased (p<0.05) after 2-4 weeks of both administration methods. Meanwhile, the efficacy of the vaccine has increased by combining BPE treatment using immersion method better than oral method. The RPS of vaccination plus extract by immersion was 83-100% and by oral administration was 83-87%. Conclusion: The present results implied that B. pandurata extract boost the efficacy of the Pseudomonas sp. vaccine by increasing the immune system and diseases resistance in tilapia.

Broad-spectrum Antimicrobial Activity of Purified Hemocyanin Subunit IIIA Isolated from Asian Horseshoe Crab, Tachypleus gigas Posted: Background and Objectives: Hemocyanin Subunit IIIA is believed to possess antimicrobial properties, but its efficacy against microbial pathogens is still unclarified. Thus, this study aimed to determine antimicrobial activities of hemocyanin subunit IIIA and to identify the best activator of this protein. Materials and Methods: The hemocyanin was partially purified using spin column affinity, its fraction was applied to Hi-Prep Sephacryl Exclusion 26/60 2-200 HR column, followed by Hi-Prep 26/10 Desalting Column on fast protein liquid chromatography. The purity of hemocyanin was validated by Matrix Assisted Laser Desorption Ionization-Time of Flight/Mass Spectrometry. The antimicrobial activity was performed by Disc Diffusion Test. Results: Purified hemocyanin subunit IIIA was identified to have a molecular weight of 72.9 kDa. SDS was found to be the best activator of hemocyanin, as indicated by elevated level of phenoloxidase. As for antimicrobial activity, hemocyanin was minimally inhibited by all bacteria strains tested (Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae), with relatively lower Minimum Inhibitory Concentration (MIC) at 0.005 g mL–1, than recorded MIC for fungal test strains. Two fungal strains (Penicillium sp. and A. niger) show susceptible response to phenoloxidase using MgSO4 as inducer. Whereas, lysate-treated CaCl2 induced susceptibility only to A. niger. Conclusion: Hemocyanin shows better antimicrobial activity than phenoloxidase because of its broad-spectrum activity against bacterial and fungal strains tested. Hence, the hemocyanin may potentially become a new antimicrobial candidate to be discovered for a future use in treatment of resistant bacteria.