EVALUATION OF THE FATTY-ACID PROFILES OF 2 FAIRY SHRIMP SPECIES, BRANCHIPUS-PASAI COTTARELLI, 1969 AND CHIROCEPHALUS-KERKYRENSIS PESTA, 1936 (CRUSTACEA, ANOSTRACA) FED DIFFERENT DIETS

Laboratory cultured fairy shrimps Branchipus pasai and Chirocephalus k erkyrensis, fed on an alga (Selenastrum capricornutum), a yeast (Sacch aromyces cerevisiae) and an HUFA enriched yeast (Lansy PZ, produced by Artemia Systems, Gent, Belgium) were evaluated for their fatty acid ( FA) profiles and total lipid content in order to obtain information an species differences in food conversion. The results indicate signific ant qualitative and quantitative differences (P<0.001) in FA profiles both of feed and of fairy shrimp species. Among the three different di ets, an appreciable lipid amount was recorded in the alga, as compared with baker's yeast which showed the poorest lipid content. The algal fatty acid profile showed adequate amounts of the EFA 18:2n6, 18:3n3 a nd 20:5n3 (the most meaningful for aquacultural purposes). The enriche d yeast was characterised by a considerable total lipid amount and by the presence of all the EFA. The overall amounts of fatty acids in the fairy shrimps correlated well with their levels in the feed (r>0.9, P <0.001). An exception was noted in the n-3 HUFA (highly unsaturated fa tty acids) and n-6 acids, among the individuals fed on yeast. Highly s ignificant differences (P<0.001) were also noted between the two fairy shrimp species fed on the same food type. When fed enriched yeast, bo th B. pasai and C. kerkyrensis profiles roughly reflected diet composi tion. However, when fed on algae or baker's yeast, the two species, th ough to different extents, exhibited higher EFA levels than those reco rded in the food. This seems to support the existence of a partial FA bioconversion capacity in fairy shrimps previously noted in the case o f the brine shrimp Artemia.