Effects of restricted food intake on neutral lipid and free fatty acid levels in the digestive gland-gonad complex and faeces of Biomphalaria glabrata (Gastropoda).

Abstract

High-performance thin-layer chromatography (HPTLC) was used to determine neutral lipids and free fatty acids in the digestive gland-gonad complex (DGG) and faeces of Biomphalaria glabrata. Three populations of B. glabrata were given varying food intakes for one week. They were either unrestricted (lettuce ad libitum plus a weekly feeding of Tetramin), restricted (15-17 mg of lettuce every two days), or starved (no food). Samples were prepared by extraction in chloroform:methanol (2:1), followed by a Folch wash (0.88% aqueous KCl). The major lipids detected in the DGG were triacylglycerols, free fatty acids and free sterols. Free fatty acids and free sterols were the major lipids detected in the snail faeces. Analysis by TLC-densitometry showed a statistically significant difference in the DGG levels of triacylglycerols and free sterols between the unrestricted and restricted groups, as well as between unrestricted and starved groups. Analysis of faecal samples revealed a significant difference in free fatty acids between unrestricted and starved groups on the seventh day.