Changes in phosphatidylcholine molecular species in the shrimp Macrobrachium borellii in response to a water-soluble fraction of petroleum.

The effect of the water-soluble fraction (WSF) of crude oil on lipid contents, lipid classes, FA, and PC molecular species was studied in high-phospholipid (hepatopancreas) and low-phospholipid (egg) tissues of a freshwater crustacean. After a 21-d exposure to a sublethal concentration of WSF, a significant decrease in shrimp total lipids was observed, although no alterations could be detected in the hepatopancreas or egg lipid contents. TAG/phospholipid ratios increased in the hepatopancreas and decreased in the eggs, suggesting alterations either in the mobilization of TAG to phospholipid pools or in the energy balance. The FA composition of phosphoglycerides in the hepatopancreas and eggs was dominated by PUFA, whereas the n-3/n-6 ratio was not affected by WSF exposure, although there was a significant increase in hepatopancreas 18:1n-9. Analysis of the PC molecular species by HPLC-ELSD showed the presence of 15 species, with 16:0/18:1, 18:1/18:2, 16:0/20:5, and 16:1/20:5 being the major species in the hepatopancreas. The PC molecular species in the eggs showed a different pattern, dominated by 16:0/18:1 and 18:1/18:2. Of the PC molecular species, 10 contained 22:6n-3, 20:5n-3, and 20:4n-6. Small amounts of di-PUFA species were also found. Exposure to WSF altered the PC molecular species in both tissues. The four major hepatopancreas molecular species and most of the ones containing PUFA decreased. This was compensated for by an increase in 16:1/18:1 (152%) and 18:1/18:1 (50%). The two major egg PC molecular species decreased, whereas the PUFA-containing ones increased. The contrasting responses of both tissues to WSF contamination suggests the presence of different homeostatic mechanisms.