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Add To Calendar 21/02/2017 15:15:0021/02/2017 15:35:00America/ChicagoAquaculture America 2017A SEASONAL COMPARISON OF PROXIMATE COMPOSITION OF MIXED CULTURES VERSUS MONOCULTURES OF Nannochloropsis salina AND Phaeodactylum tricornutum IN SEMI-CONTINUOUS OUTDOOR RACEWAYS Room 5The World Aquaculture Societyjohnc@was.orgfalseanrl65yqlzh3g1q0dme13067DD/MM/YYYY

A SEASONAL COMPARISON OF PROXIMATE COMPOSITION OF MIXED CULTURES VERSUS MONOCULTURES OF Nannochloropsis salina AND Phaeodactylum tricornutum IN SEMI-CONTINUOUS OUTDOOR RACEWAYS

Brooke Konkle*, Nathan Huysman, John Scarpa, and Anthony Siccardi III
 
Texas A&M University at Corpus Christi
 Fisheries and Mariculture Program
Corpus Christi, TX  78412
bkonkle@islander.tamucc.edu

Aquaculture is continually growing in its contribution as a provider for human-consumed seafood. Diets containing large amounts of fish meal and oil are used for aquacultured shrimp and fish. There is a growing demand for these limited marine feed ingredients, which has not only increased feed costs but has also added more pressure to the world's fisheries. Alternatives to fish meal and oil must be developed in order to lessen the dependence on these finite resources. Previous research has demonstrated that proteins and lipids extracted from microalgae can replace a significant amount of fish meal in aquaculture diets. Mixed cultures of microalgae have shown potential benefits in biomass production for biofuel research. This production technology also has the potential to produce cultures with optimum amino acid and fatty acid levels (profiles) as an aquatic animal feed grade ingredient. Seasonal fluctuations in temperature, salinity, and radiation can affect the lipid and protein content and composition of the microalgae. As many cultures are maintained outdoors, the impact of these variations must be determined in order to accurately predict culture yields of proteins and lipids.

The current study was designed to compare production characteristics and protein and lipid content between monocultures and a mixed culture of the microalgae Nannochloropsis salina and Phaeodactylum tricornutum produced in outdoor systems. Twelve (n=4/treat.) outdoor 600L raceway systems (surface area 2.8m2) were inoculated with cultures at similar ash-free dry weight/L and then maintained over a 90-day period (Nov. 2015 to Feb. 2016). The microalgae culture in each system was circulated by a rotating paddlewheel and pH maintained between 7.6 and 8.0 by CO2 injection controlled with a pH-activated solenoid. Temperature, salinity, and pH of each system were measured twice daily with a portable meter. Cultures were harvested (25-75% of volume depending on microalgae density) every 3-7 days (i.e., after cultures reached stationary growth). Before harvesting, culture samples from each system were collected and stored for protein and lipid analysis.

The proximate composition of the biomass over the course of the trial will be presented and correlated to weather parameters. This research was supported by a grant issued by the Department of Energy.

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