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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/30

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AGROVOC Keyword: search.filters.agrovoc.aquacultureStart date: 2010

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    Antimicrobial activity of macrofungal basidiomycetous mycelia against Vibrio spp.
    Bagacay, Jann Felnesh Exe V. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2023-06)
    Aquaculture is vital for global food security, producing 50% of the world’s fish. However, infectious diseases caused by fish pathogens like Vibrio species can lead to significant production losses. To address this issue, antimicrobial agents are commonly used. Macrofungal fruiting bodies and mycelia produce bioactive compounds with antimicrobial properties. This study aims to: (a) assess antimicrobial activity in isolated macrofungal samples against the fish bacterial pathogens Vibrio parahaemolyticus and Vibrio cholerae, (b) compare two methods (agar plug and crude extracts) for antimicrobial activity, (c) determine the minimum inhibitory concentration (MIC) using agar well diffusion and the agar plug methods, and (d) identify the macrofungal isolate with the highest antimicrobial activity. Ten morphospecies were collected from the University of the Philippines Visayas Miagao Campus. The samples were evaluated using the agar plug and agar well diffusion methods. The results showed antimicrobial activity against Vibrio cholerae and Vibrio parahaemolyticus. The activity index ranged from 0 to 0.83 and 0.22 to 0.78 for agar wells, and 0 to 1.00 and 0.70 to 1.30 for agar plugs, against V cholerae and V. parahaemolyticus, respectively. Termitomyces globulus and Trametes sp. 1 exhibited the highest activity indices using the agar plug and agar well diffusion methods, respectively. Statistical analysis confirmed significant differences in antimicrobial activity against both test organisms. These findings demonstrate the potential of macrofungi as a valuable source of antimicrobial compounds for controlling fish pathogens in aquaculture. Further research could lead to the identification and utilization of these compounds to minimize production losses and improve disease management in aquaculture.
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    Growth and nutritional content of red seaweed Gracilaria bailinae (Zhang et. al., 1995) grown under different fertilization scheme
    Almojuela, Kristine Marie T. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2012-04)
    The accelerated development of fish aquaculture has caused many environmental problems. The most evident effects resulting from this activity is the increase in organic material, the reduction in dissolved oxygen and the excessive rise in inorganic nutrients such as nitrogen, phosphorous and carbon dioxide. The integration of seaweeds to fed cultured species has long been recognized as promising approach to reduce the excess nutrients released by aquaculture activity. The nitrogen and phosphate uptake kinetics, growth and nutritional content of the seaweed Gracilaria bailinae were studied in a series of outdoor tanks, fertilized with commercial fertilizer (NH4CI, NaNO3, and Na2HPO4) and shrimp culture waste water. The nutritional content of G. bailinae before and after fertilization was also determined through proximate analysis. Results showed a significant removal of dissolved nutrients by G. bailinae, although definite uptake rate could not be determined since the data were erratic and Michaelis-Menten model could not be applied. Seaweeds fertilized with shrimp waste water showed best specific growth rate (1.37±0.2 % d-1) over other fertilization scheme. This suggests that shrimp pond effluents could promote good growth on G. bailinae. Local G. bailinae had high protein content per se (14%) but became more enhanced when fertilized with commercial or shrimp waste water (23-32%). In contrast, its carbohydrate content dropped when heavily fertilized from 39% to 19%.