Abstract
Thin layer chromatography (TLC) was used to determine neutral lipids in snail conditioned water (SCW) and feces from Biomphalaria glabrata snails infected with Echinostoma caproni. Samples were extracted in chloroform–methanol (2:1), and the neutral lipids were separated on silica‐gel plates with a mobile phase consisting of petroleum ether–diethyl ether–glacial acetic acid (80:20:1). Zones were detected with phosphomolybdic acid reagent and quantified by densitometry. Qualitative analysis of SCW samples showed the presence of free sterols, free fatty acids, and triacylglycerols; qualitative analysis of fecal samples showed free sterols, free fatty acids, and unidentified pigments. Quantitative analysis of SCW with feces (SCW‐WF) from infected snails showed 7.35 ± 2.3 µg 2−1 mL−1 free fatty acids compared with uninfected controls, which had 8.05 ± 0.54 µg 2−1 mL−1. Quantitative analysis of SCW without feces (SCW‐WOF) showed that infected snails contained 4.76 ± 0.64 µg 2−1 mL−1 of free fatty acids compared with uninfected controls, which had 5.88 ± 0.34 µg 2−1 mL−1. Free fatty acids were the major fraction in snail feces. Samples from infected snails had 0.0224% ± 0.0022% compared with the uninfected controls, which had 0.0353% ± 0.0036%. The free fatty acids composition of the feces for infected snails was significantly lower than that of the uninfected samples (Student's t‐test, P < 0.05).
Acknowledgment
J.L. Schneck and S.R. Bandstra were supported by Lafayette College's EXCEL Scholars Program.