World Aquaculture Society Meetings

Add To Calendar 21/02/2017 13:45:0021/02/2017 14:05:00America/ChicagoAquaculture America 2017SELECTION OF MICROALGAE CULTURES BASED ON AMINO ACID PROFILES AND PROTEIN CONTENT TO BE USED AS FISH MEAL REPLACEMENTS IN AQUACULTURE DIETS Room 5The World Aquaculture Societyjohnc@was.orgfalseanrl65yqlzh3g1q0dme13067DD/MM/YYYY

SELECTION OF MICROALGAE CULTURES BASED ON AMINO ACID PROFILES AND PROTEIN CONTENT TO BE USED AS FISH MEAL REPLACEMENTS IN AQUACULTURE DIETS

Nathan Huysman*, Delbert Gatlin, Jacqueline Mitchell, John Crockett, Anthony Siccardi
 
Texas A&M AgriLife Research
Corpus Christi, TX 78418
 Nathan.Huysman@ag.tamu.edu

As world supplies of fish meal dwindle and prices of fish meal rise, microalgae has been proposed as a replacement for fish meal and oil in aquaculture diets. Various fish and crustacean species have been shown to successfully digest and grow with differing percentage fish meal replacements with microalgae. This presentation will focus on the basic course of action we employ in identifying microalgal species that can be utilized to create a favorable fish meal replacement with good amino acid profiles and percent protein in the aquaculture industry.

Amino acid and protein components of Nannochloropsis salina and Phaeodactylum tricornutum from outdoor trials will be presented. As a comparison, three incubator trials utilizing five different species of microalgae (Tetraselmis sp., Platymonas sp., Cylindrotheca sp., Cyclotella meneghiniana, and Thalassiosira sp.) were conducted to attempt to identify possible microalgal species that could be utilized in conjunction with N. salina and P. tricornutum to create a more suitable amino acid profile for the aquaculture feed industry.

Three incubator trials (Tetraselmis sp., Platymonas sp., Cylindrotheca sp., Cyclotella meneghiniana, and Thalassiosira sp.) were ran under controlled conditions in a constantly illuminated and temperature controlled (22oC) incubator. Cultures were supplied with 24hr. atmospheric aeration at ~0.2 L/min. Two different nutrient formulations were used for growth: f/2 (Bigelow Laboratories) and our traditional ammonium sulfate and phosphoric acid based nutrients with matched molar levels to f/2. Absorbance growth curves (750nm) were built based on AFDW measurements for each individual species.

Flasks (1L) were inoculated to ~0.04 g/L AFDW based on absorbance using chlorinated and DE filtered natural SW salinity adjusted to ~30ppt. After initial nutrient supplementation, each flask was placed into incubator randomly. Trial duration was 10 days to allow for complete nutrient utilization. Each flask was sampled daily for absorbance and nutrient levels.

Results will be presented showing the amino acid profiles and protein content of the five tested strains of microalgae. This presentation will also discuss the possibility of using the selected species in mixed culture systems to enhance the overall viability of using microalgae as a fish meal replacement in aquaculture diets.

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