Effect of enriched Brachionus plicatilis and Artemia salina nauplii by microalga Tetraselmis chuii (Btcher) grown on four different culture media on the growth and survival of Sparus aurata larvae

摘要

The growth, developmental stages and survival rates of?Sparus aurata?larvae fed with?Brachionus plicatilis?and?Artemia salina?nauplii enriched by microalgaTetraselmis chuii?were studied. Two experiments were carried out;?the first concerning with culturing the microalga?(T. chuii)?in four different media, then using these cultures for enrichment of the rotifer (B. plicatilis) and brine shrimp (A. salina)nauplii). The second experiment was considered the application of enriched?B. plicatilis?and?A. salina?were used for feeding?S. aurata?larvae. Mean growth and survival rate of larvae were used for evaluation of the best medium. Erdschriber medium was considered the best algal medium compared with the other media used because the cell density were the highest (24.5 X 106?cell.ml-1) on the 11 day (late logarithmic/early stationary phase of growth), the highest survival and greatest growth rates of?S. aurata?larvae were noticed. The total fatty acids in?T. chuiiespecially the polyunsaturated fatty acid were represented by content 5.5% [arachidonic acid (ARA)], 4.8% [eicosapentaenoic acid (EPA)] and 5.0% [docosahexaenoic acid (DHA)] to the total fatty acids. The higher production of total fatty acids in?B. plicatilis?fed on?T. chuii?grown in Erdschriber medium was due to the accumulation of polysaturated fatty acids (PUFAs) (94.7% of the total lipids). EPA was absent, while DHA (22:6ω3) was enhanced and constituted 657.49 μg.g-1(91.4% of the total fatty acids). Saturated fatty acids were detected more than unsaturated one (63% of the total fatty acids), in case of?A. salina?fed on?T. chuiigrown in Erdschriber medium, especially the short chain fatty acids (C16:0, C18:0 and C21:0). On the other hand PUFAs constituted 22.3% of the total fatty acids, due to the presence of DHA which formed 8.0% of the total fatty acids, while ARA and EPA were absent. The results show that?B. plicatilis?and newly hatched Artemiaenriched with?T. chuii?grown on was effective for good growth and survival rate of?S. aurata?larvae.