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UPV Theses and Dissertations

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    Analysis of the lipid content of micro algae species used in Philippine aquaculture for their potential in biodiesel production
    Ferriols, Victor Marco Emmanuel N. (Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2008-03)
    This study looked into the proximate lipid content of four micro algal species (Chaetoceros calcitrans, Tetraselmis tetrahele, Nannochloropsis sp., and Chlorella sp) and one macrophyte (Chaetomorpha sp.) commonly used in Philippine aquaculture. Prior to the proximate analysis using the method described by Bligh and Dyer (1959), the four micro algal species were cultured for five days in 1 L vessels fertilized with TMRL enrichment media. Proximate gravimetric analysis showed that the average lipid content of Tetraselmis tetrahele at 24.11% was significantly higher (p < 0.01) when compared to all the algal species tested. Comparing the mean lipid content of all micro algal species against that of the macrophyte also revealed a significantly higher (p < 0.01) lipid content at 17.40%. Growth rates for all the micro algal species over the culture period was also measured, with the highest growth rate exhibited by T. tetrahele at 1.15 divisions per day. Projected estimates for micro algal production yields of oil from a 1-hectare pond at 0.5 m depth were also calculated from the lipid analysis data, a showing that the highest yield of oil (7.29 tons) can be attained by culturing T. tetrahele. This number was higher than estimated reports for oil production from an area of 1 hectare dedicated to either jatropha (1.7 tons) or coconuts (5.0 tons). This makes the culture of micro algal species a potential option for producing feedstock for biodiesel production.
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    Growth development, survival and settlement rate of sandfish (Holothuria scabra) larvae reared using different microalgae and settlement and settlement cues
    Sibongga, Rema C. (University of the Philippines Visayas, 2017-07)
    ABSTRACT Growth, development and survival of Holothuria scabra larvae fed with different microalgae were studied. In the first experiment, Chaetoceros calcitrans, Rhodomonas sp. and Tetraselmis tetrathele at 10000, 20000, 30000 and 40000 cells ml-1 were compared. Larvae fed with Rhodomonas sp. at 10000 cells ml'1 had the highest mean body length (BL) at late auricularia (1032.41±38.70 μm). However, those fed with C. calcitrans at 20000 cells ml'1 showed higher daily growth rate (DGR) of 31.4±5.2 pm d-1. Development to 50% competent larvae was shorter using C. calcitrans at 20000 and 30000 cells ml'1. At 12 days post-fertilization (DPF), larvae fed with C. calcitrans at 20000 and 40000 cells ml'1 showed significantly higher % doliolaria (p<0.05) and those fed at 20000 cells ml-1 showed highest survival of 53% at 14 DPF. In the second experiment, three combinations of microalgae containing 10000 cells ml'1 of each microalga were used: C. calcitrans and Rhodomonas sp., C. calcitrans and T. tetrathele, and Rhodomonas sp. and T. tetrathele. Larvae fed with mixed C. calcitrans and Rhodomonas sp. showed significantly higher mean BL at late auricularia (991.0±15.8 pm) and DGR (43.8±9.9 μm d-1) (p<0.05). Larvae showed faster development and higher survival of 86% at 10 DPF. In summary, C. calcitrans at 20000 cells ml'1 is recommended as a single diet while a combination of C. calcitrans and Rhodomonas sp. as a mixed diet. Settlement of H. scabra on substrates with different cues was also investigated using corrugated plastic sheets (CPS) as substrate and Navicula, C. calcitrans paste and Spirulina paste as cues. CPS without cue served as control. Although no significant differences, Spirulina paste showed highest settlement rate (88.54%) followed by Navicula and C. calcitrans paste. Control showed significantly lowest settlement rate. Therefore, Spirulina paste best induced settlement of H. scabra. However, Navicula and C. calcitrans paste may be used as cheaper settlement cue substitutes.