FATTY ACID PROFILE AND NUTRITION VALUES OF MICROALGA (Thalassiosira pseudonana) COMMONLY USED IN WHITE SHRIMP (Litopenaeus vannamei) CULTURING

Microalga Thalassiosira pseudonana is an important feed item in the aquaculture industry nowadays and its biomass is essential for white leg shrimp seeding production. Microalga T. pseudonana were grown under optimal conditions (salinity of 30 - 31 ‰; pH 7.5 - 8.5; temperature 25 - 27 o C; light intensity 5.5 klux with light: dark period 12:12 h; alkalinity 150 - 180 ppm; media of AGP 20 %; initial cell density 0.2 x 10 6 cells/ml; 24 hour aeration mode) and harvested during log phase after 6 days of cultivation. The obtained results showed that  microalga T. pseudonana  possess both EPA (eicosapentaenoic acid, C20:5 n-3) and DHA (docosahexaenoic acid, C22:6 n-3) fatty acids. Particularly, its fatty acid composition is mainly C16:0 (38.060 % compared to total fatty acid - TFA), C16:2n - 4 (12.850 % TFA), 16:3n - 3 (8.873 % TFA), C20:5n - 3 (16.423 % TFA) and 22: 6 (n - 3) (1.650 % TFA). Also, the C16:1n - 7 (6.147 %), C16:1n - 9 (4.737 % TFA), C18:1n - 7 (1.370 % TFA), C18:1n - 9 (2.063 % TFA) and C20:1n - 7 (0.677 % TFA) which were obtained those play a crucial role in aquaculture activities. Additionally, the total content of SFAs, MUFFAs and PUFFAs were 42.539, 14.994 and 42.443 % TFA, respectively. The protein, carbohydrate, chlorophyll a, carotenoids, lipid contents was reach 13.20 ± 0.01 %, 9.96 ± 0.12 %, 1.01 ± 0.13 %, 0.15 ± 0.01 %, 20.79 ± 0.24 % of dry cell weight, respectively. Moreover,  T. pseudonana biomass contains a large variety of minerals and micronutrients such as Na (27.80 %/kg), K (0.93 %/kg), I (55.10 mg/100g), Fe (222.74 mg/kg), Cu (1.96 mg/kg), Mn (3.11 mg/kg), Mg (2.52 %/kg), Ca (0.97 %/kg), Co (< 0.10 mg/kg) and undetectable B. Importantly, the heavy metals contents such as Cd, Pb, As and Hg was met to the Vietnam standard for aquaculture feed.