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Committee Member: search.filters.committeemember.Fortes, Norma R.

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    Effect of elevated carbon dioxide and phosphorus on nitrogen uptake, lipid content, and growth of Tetraselmis sp.
    Ferriols, Victor Marco Emmanuel N. (Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2011-04)
    Effect of elevated carbon dioxide (CO2) and phosphorus levels on nitrogen uptake, lipid content, and growth of Tetraselmis sp. were investigated. Cultures of Tetraselmis sp. were added with CO2 and phosphorus at concentrations above those currently used in aquaculture practices in a factorial experiment. Three levels of CO2 (no addition, 5% v/v, and 10% v/v of the incoming air for aeration) and three levels of phosphorus added as NaH2PO4 (5, 10, 20 mg L’1) in modified F medium with NH4+ as the primary nitrogen source were used. Optical density (680 nm) and residual NH3-N in the culture medium were monitored daily over a culture period of 6 days. Relative growth rate (k'), nitrogen uptake (pg NH3-N cell’1 day1), and lipid content (% dry weight) were calculated and determined at the end of the culture period. No interactive effect between phosphorus and CO2 levels was observed in all variables measured (p > 0.05). Highest growth rate (k = 1.82±0.04), nitrogen uptake (0.316±0.008 μg NH3-N cell1 day1), and lipid content (10.95±0.15 %DW) were exhibited at 10% CO2 supplementation. Growth and nitrogen uptake were similar in treatments with elevated levels of phosphorus, but lipid yield (9.41±0.27 %DW) was lowest at 20 mg L1 of phosphorus supplementation (p < 0.05). These results showed the critical role of CO2 in nitrogen uptake, lipid content, and growth of Tetraselmis sp. It also indicates the potential of this algal species for waste water remediation, biofuel production, and carbon sequestration.
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    Evaluation of different carbon sources used in the biofloc technology (BFT) culture of Litopenaeus vannamei
    Alaban, Leovigildo Rey S. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2011-04)
    ABSTRACT An evaluation of different carbon sources used in Biofloc technology (BFT) culture of L. vannamei was done. The experiment included five treatments: Control, RB (Rice Bran), Tap (Tapioca), Mol (Molasses) and COMBI (Molasses + Rice Bran). Evaluation of biofloc parameters - Total Suspended Solids (TSS) and Settleable Solids (SS)- showed an increasing trend in treatments with molasses (Mol and COMBI) as the culture progressed. This became significantly different (P < 0.05) in the later phase of the culture. The evaluation of environmental parameters included TAN (Total Ammonia Nitrogen), NO2-N (Nitrite Nitrogen) and Chlorophyll a. In treatments with rice bran (RB and COMBI), TAN showed an increasing trend, becoming significantly different with the rest in the later phase of the culture (P < 0.05), while NO2-N were maintained below toxic levels. Chlorophyll a didn’t show any discernable pattern. The effect on L. vannamei was evaluated based on growth (ABW-Average Body Weight, SGR-Specific Growth Rate and FCR- Feed Conversion Ratio) and yield (Survival and Biomass) parameters. Treatments with rice bran showed faster growth rates compared to the rest (P < 0.05) for most part of the culture period. However, analyses of growth parameters based on harvest data don’t show any significant difference in SGR and final ABW for all treatments. Further, poor water quality in these treatments lead to heavy mortalities which caused FCR and Biomass to be significantly different (P < 0.05) from the rest of the treatments.