Differences in the fatty acid composition of larvae and metamorphosing sea lampreys, Petromyzon marinus

Abstract

This study was designed to evaluate biochemical changes in the fatty acid (FA) compositions of selected lipid depot (kidney and liver) and absorption (intestine) organs in larvae and metamorphosing sea lamprey, Petromyzon marinus. Palmitic or stearic acids were generally the predominant saturated fatty acids (SFA) before and during metamorphosis, but the greatest proportion of myristic acid occurred in renal triacylglycerol (TG). Monoenes, dienes, and polyenes consist mainly of 16:1, 18:1, and 20:1, 18:2 and 20:2v6, and 18:4v3, respectively. Alterations in these predominant fatty acids occurred during lamprey metamorphosis, but depended on tissue, lipid class, and developmental status. During metamorphosis, kidney TG and phospholipid (PL) classes tended to mobilize SFA and enhance the fatty acid unsaturation, as indicated by increased unsaturatedysaturated ratio, unsaturation index (USI), and total mean chain length (MCL). There was a tendency to increase saturation in the fatty acids of liver TG and PL classes and intestine TG, FA and monoacylglycerol (MG) classes, but to increase unsaturation in the fatty acids of liver cholesteryl ester (CE), FA and MG classes and intestine PL and CE classes from larva or stage 3 to stage 7. Increased polyunsaturated fatty acids in kidney TG and PL from larvae to stage 5 transformers and intestine PL and CE from stage 3 to stage 7 transformers may reflect an osmoregulatory pre-adaptation. The presence of branched-chain SFA (BCSFA) and the odd number of fatty acids (ONFA) indicated a significant role of detritivores in the benthic larvae. Decreased abundance of BCSFA, ONFA, and 18:2 dienes occurred in the transformed intestine TG as non-trophic metamorphosis proceeded. These data suggest that sea lamprey metamorphosis may proceed in a habitat, dietary, osmoregulatory, energetic, and developmental pre-adaptation of fatty acid composition from benthic filter-feeding larvae to pelagic parasitic juveniles. ᮊ

Chemical Characterization of Lipophilic Constituents in the Skin of Migratory Adult Sea Lamprey from the Great Lakes Region

“…These CEs contributed to 2.53% of the total lipophilic constituents of adult migratory sea lamprey skin. Kaoa et al, reported an increase in monounsaturated CEs while decreasing the saturated CEs in liver and intestine during the larval metamorphosis of sea lamprey [32]. Our results on adult sea lamprey skin showed high amounts of monounsaturated cholesterol esters relative to saturated CEs, which is in support of the turnover of saturated CEs in larvae during metamorphosis to adult.…”

“…Our results on adult sea lamprey skin showed high amounts of monounsaturated cholesterol esters relative to saturated CEs, which is in support of the turnover of saturated CEs in larvae during metamorphosis to adult. In addition, our results also confirmed significantly high amounts polyunsaturated cholesterol esters (ω-6 C20:4, and ω-3 C20:5) compared to metamorphosing larvae, where trace amounts or absence of polyunsaturated cholesterols reported from liver and intestine [32]. …”

“…Liver and intestinal tissues from metamorphosing larvae of sea lamprey in the Great Lakes region have been reported to contain cholesterol ester and lipids, identified by GC analysis of the tissue extract [32]. In this study, we report the isolation of pure cholesterol esters from adult sea lamprey skin extract and its characterization by NMR and GCMS methods (Table 1).…”

“…During metamorphosis, larvae of sea lamprey begin to store significant amounts of triglycerides in kidney, liver, fat column, subcutaneous tissues and myosepta as energy reserves for migration, which requires maximum energy input [33,34]. Our lipid analysis of sea lamprey skin showed 30.3% of triglycerides in the total lipophilic compounds isolated.…”

Comparison of the fatty acid profile of muscle neutral lipids and phospholipids of up-river anadromous sea lamprey (<i>Petromyzon marinus</i> L.) from three Portuguese river basins

“…Several studies have investigated the lipid metabolism and the tissues lipid levels which occur in the life cycle of P. marinus but generally data are available only on the larval and metamorphosing phases (Kao et al, 2002) or for the adult landlocked form (leBlanc et al, 1995). Beamish et al (1979) described the large fluctuations in the total lipid content of various stages in the adult phase (small and large feeding adults, early immature and nearly mature migrants, spawning and spent reproducers) of the life cycle of anadromous sea lamprey and related them to feeding, migration and reproduction.…”