Lipid composition of the pacific lion-paw scallop, Nodipecten subnodosus, in relation to gametogenesis

Abstract

International audienceKnowledge on the energy distribution during the reproductive cycle of the giant lion-paw scallop, Nodipecten subnodosus is limited, but necessary for aquaculture purposes. In a previous work, we found that natural food availability can sustain the full cost of gametogenesis in optimal environmental conditions. The present study analyses the lipid and sterol classes' composition of several tissues during gametogenesis. In female gonads, the quantity of triacylglycerol (TG) increased parallel to gametogenesis from December (spawned gonads, 0.7 mg g(-1) or 7% of total lipids) to June (ripe gonads, 52 mg g(-1) or 66% of total lipids). In male gonads sampled in June, the concentration of TG (0.7 mg g(-1) or 3.5% of total lipids) and esterified sterols was significantly lower than in female gonads. Total phospholipids (PL) increased two-fold in female gonads of scallops sampled in June compared to the other months, which could be a result of oocyte production and growth, but no differences were found in the concentration of PL or in free sterol composition between male and female gonads. TG concentration in the digestive gland was similar in December and February (37-3 8 mg g- 1 or 68% of total lipids), but increased eight-fold by April and remained high in June (252-277 mg g(-1) or 90% of total lipids). Together with the increase in esterified sterols, these data suggest an increase in food availability during these months. A lack of decrease of TG levels in digestive gland during gonad development is in accordance to sufficient food availability in this location to satisfy the energetic demands of gametogenesis. Cholesterol was the principal sterol found in all tissues; its concentration, as well as the concentration of several phytosterols, remained constant throughout the maturation process, except in digestive gland where they increased from December to June, further supporting an increased availability of food. However, the presence of several phytosterols in substantial concentrations, mainly brassicasterol and 24-methylenecholesterol in gonad and somatic tissues, further supports a specific physiological role of these sterols in pectinids. (c) 2007 Elsevier B.V. All rights reserved

Changes in fatty acids, sterols, pigments, lipid classes, and heavy metals of cooked or dried meals, compared to fresh marine by-products

“…As expected, squid viscera and shrimp heads had high levels of cholesterol, while the phytosterols present in scallop viscera are similar to those reported in lions-paw scallop (Palacios et al, 2007). In scallops viscera, the loss of esterified sterols (ES) after cooking was accompanied by an increase in free sterols (FS), but this was not the case in squid viscera, indicating not only hydrolysis of ES from the cytoplasm, but also oxidation of FS released by hydrolysis from ES, or from the membrane, and maybe loss of oxidized sterols in the cooking broth.…”

“…Sterols from the lipid extract were transesterified with 2 mL sodium methoxide (Sigma) and separated on a silica capillary column (65% biphenyl/35% polydimethylsiloxane, RESTEK, 30 mx 0.25 mm × 0.25 m), using helium and a thermal gradient of 200 to 290 • C at 5 • C/min, as described by Palacios et al (2007) …”

“…Samples of lipids were run on thin layer chromatography coupled for detection by flame ionization (Iatroscan TLC/FID MK-5, Iatron Laboratories, Tokyo, Japan) using chromarods S-III and a mobile phase of hexane:ethylacetate:diethylether:formic acid solution (90:7:3:1), as described in Palacios et al (2007).…”

Muscle and Roe Lipid Composition in Diploid and Triploid Scallops

“…General lipid class composition was measured with an Iatroscan TLC/FID MK‐5 analyzer (Iatron Lab. Inc., Tokyo, Japan) and chromarods S‐III, in a mobile phase of hexane/ethyl acetate/diethyl ether/formic acid (91:6:3:1, v/v/v/v) as described by Palacios et al. (2007).…”

“…Neutral and polar lipid fractions were separated on a silica‐gel microcolumn, collected in vials containing an internal standard (23:0) and buylated hydroxytoluene (BHT), as described by Palacios et al. (2005).…”