15 MAY 1999
PERFILES DE ACIDOS GRASOS DE NAUPLIOS DE 4 POBLACIONES MAXICANAS DE ARTEMIA FRANCISCANA, Y ADULTOS CULTIVADOS EN DIFERENTES CONDICIONES EXPERIMENTALES
(FATTY ACID PROFILES OF NAUPLII FROM 4 MEXICAN ARTEMIA FRANCISCANA POPULATIONS AND OF ADULTS, CULTURED AT DIFFERENT EXPERIMENTAL CONDITIONS - in Spanish)
Thesis by N.A. de J. Ramos Delgado, Universidad Autonoma de Baja California, Facultad de Ciencias Marinas, Ensenada, BC, Mexico, 1999, 47 pp.
Summary :
The fatty acid profiles of newly hatched nauplii of natural Artemia
franciscana populations from Oaxaca, San Luis Potosi, Texcoco, Cuatro Cienegas and Great Salt Lake were characterized. The fatty acid profiles of adult Artemia franciscana from Great Salt Lake, cultured in four different salinity and temperature conditions were determined as well. The cysts of the natural populations were decapsulated using the sodium hypochlorite method, and the newly hatched nauplii were lyophilised and frozen to -70 C until analysis. The adults were cultured in an experimental 2 x 2 design (temperature 22 and 26C; salinity 30 and 60 ppt) and fed with the live microalga Dunaliella sp. The fatty acid analysis was performed using gas chromatography and mass spectrometry. Considerable percentages (4-19% of the total of identified fatty acids) were identified as iso and anti-iso forms of 15 and 17 carbon atoms, both in newly hatched nauplii and in adults, which demonstrates the presence of bacteria associated with Artemia franciscana. The largest concentration of total fatty acids (TFA) was found in the sample from Texcoco, with 9150 micro g/g dry weight, which is obviously the sample with the highest nutritional value, due to its percentage of PUFA (21.6%), 18 :2w6 (4.5%) and 20 :5w3 (1%). The fatty acid profile of the experimental culture samples shows that culture conditions of 22 C and 60 ppt are most favorable to obtain a high nutritional value, since in these conditions the largest concentration of TFA (11,610 micro g/g), high percentages of PUFA (32.3%) and 18:3 (21.5%) were obtained. Moreover, only in these conditions 20:5w3 (0.14%) was observed. According to the classification of Watanabe et al. (1978), the samples of newly hatched nauplii of the natural populations are of the marine type, while the adults of the experimental cultures belong to the fresh-water type.