Effects of different extraction solvents on rotifers(Brachionus rotundiformis) lipids extraction

Effects of lipids extraction on freeze-dried rotifers(Brachionus rotundiformis) by extraction solvents of different mixing proportion with different extracting times were studied.Three extraction solvents were designed(chloroform: methanol(V/V) 2:1,1:1,1:2,benzene: petroleum ether(V/V) 2:1,1:1,1:2,acetone: petroleum ether(V/V) 1:4,3:7,2:3) to extract freeze-dried rotifer lipids with 1–3 times extraction.The lipids yield and saponifica-tion numbers were determined and were compared with the Soxhlet extractor method(national standard).Results showed that the extracting times did not significantly(P0.05) affect lipid content in all treated groups,and opti-mum solvent proportion was determined to be chloroform: methanol 2:1,benzene: petroleum ether 1:2 and acetone: petroleum ether 2:3.The lipid content and saponification number of acetone: petroleum ether 2:3 treatment were 9.71% and 198,respectively,and were significantly(P0.05) higher than that of the Soxhlet extractor method and other treatments.The results suggest that one time extraction by acetone: petroleum ether 2:3 would be the opti-mum treatment for lipids extraction on freeze-dried rotifers.