Lipid class composition of the viviparous yellowtail rockfish over a reproductive cycle

Triacylglycerols (TAG) were the dominant lipids in liver tissue of both sexes of the viviparous yellowtail rockfish Sebastes flavidus during the spring and summer when greatest feeding occurred. Significant declines in liver TAG during the winter corresponded to increased concentrations of polar lipids (PL), the main component of cell membranes. Elevated PL in female livers relative to those of males preceded the period of ovarian enlargement and may be attributed to the production of vitellogenin. During late vitellogenesis and gestation, ovaries contained significantly elevated concentrations of PL, TAG, and cholesterol. Since yellowtail rockfish are highly fecund and viviparous, large quantities of ovarian PL are required for proliferation of the cell membranes in developing larval tissues. TAG accumulated in ovaries in lower concentrations than PL and were likely metabolized as the main source of energy during gestation. This pattern of ovarian PL concentrations exceeding those of TAG and the presence of oil globules, may be unique to highly fecund, viviparous teleosts and signify an alternative profile to those previously documented for oviparous species. Testes at maximum I _G were only 7% of maximum ovarian size, composed of mainly PL, and lacked a defined lipid dynamic pattern across the reproductive cycle.     

Transfer of n-3 and n-6 polyunsaturated fatty acids from yolk to embryo during development of the king penguin

This study examines the transfer of lipids from the yolk to the embryo of the king penguin, a seabird with a high dietary intake of n-3 fatty acids. The concentrations of total lipid, triacylglycerol (TAG), and phospholipid (PL) in the yolk decreased by ~80% between days 33 and 55 of development, indicating intensive lipid transfer, whereas the concentration of cholesteryl ester (CE) increased threefold, possibly due to recycling. Total lipid concentration in plasma and liver of the embryo increased by twofold from day 40 to hatching due to the accumulation of CE. Yolk lipids contained high amounts of C(20-22) n-3 fatty acids with 22:6(n-3) forming 4 and 10% of the fatty acid mass in TAG and PL, respectively. Both TAG and PL of plasma and liver contained high proportions of 22:6(n-3) ( approximately 15% in plasma and >20% in liver at day 33); liver PL also contained a high proportion of 20:4(n-6) (14%). Thus both 22:6(n-3) and 20:4(n-6), which are, respectively, abundant and deficient in the yolk, undergo biomagnification during transfer to the embryo.     

Milk Fat Content and DGAT1 Genotype Determine Lipid Composition of the Milk Fat Globule Membrane

During secretion of milk fat globules, triacylglycerol (TAG) droplets are enveloped by a phospholipid (PL) trilayer. Globule size has been found to be related to polar lipid composition and fat content, and milk fat content and fatty acid composition have been associated with the diacylglycerol acyltransferase 1 (DGAT1) K232A polymorphism; however, the association between the DGAT1 polymorphism and fat globule size and polar lipid composition has not been studied. The ratio between polar and neutral lipids as well as the composition of the polar lipids in milk has industrial as well as nutritional and health implications. Understanding phenotypic and genotypic factors influencing these parameters could contribute to improving milk lipid composition for dairy products. The focus of the present study was to determine the effect of both fat content and DGAT1 polymorphism on PL/TAG ratio, as a marker for milk fat globule size, and detailed PL composition. Milk samples were selected from 200 cows such that there were equal numbers of samples for the different fat contents as well as per DGAT1 genotype. Samples were analyzed for neutral and polar lipid concentration and composition. PL/TAG ratio was significantly associated with both fat content and DGAT1 genotype. Phosphatidylinositol and phosphatidylserine concentrations were associated with fat content*DGAT1 genotype with a stronger association for the AA than the KK genotype. Sphingomyelin concentration tended to interact with fat content*DGAT1 genotype. Phosphatidylethanolamine (PE) concentration showed a biphasic response to fat content, suggesting that multiple biological processes influence its concentration. These results provide a new direction for controlling polar lipid concentration and composition in milk through selective breeding of cows.     

Plasma and ovarian thyroxine levels in relation to sexual maturation and gestation in female Sebastes inermis

Plasma T₄ (L-thyroxine) concentrations in the viviparous rockfish Sebastes inermis showed a peak (119·3±27·8 ng ml⁻¹) during the development of embryos. Ovarian T₄ concentrations increased during vitellogenesis and final maturation and decreased during embryogenesis.However, total T₄ content within the ovary increased continuously up to the larval stages. Plasma oestradiol-17β, (E₂) concentrations peaked at the final maturation stage and then recovered to the level seen during the non-reproductive periods. Plasma testosterone (T) concentrations showed a peak (5·33±1·08 ng ml⁻¹) at the embryo stage and high levels were maintained throughout the gestation period. Plasma T₄ concentrations during the embryo stage and ovarian T₄ content during vitellogenesis were much higher than the levels reported in oviparous fishes. These data suggest that in viviparous rockfish, T₄ may be required for sustaining gestation or embryo development within the maternal body. In addition, the high content of total T₄ in the ovary implies that there probably does exist a maternal-embryo relationship during gestation as well as during vitellogenesis.     

Lipid class dynamics and storage depots in juvenile weakfish Cynoscion regalis and their application to condition assessment

Lipid class dynamics, the pattern of change in the primary form and location of lipid stores and their relationship with standard length (L(S) ), were investigated in collections of young-of-the-year weakfish Cynoscion regalis for the purpose of determining the utility of this analysis as an indication of condition. The separation of total lipids into individual classes and the analysis of potential storage depots revealed the general patterns of lipid class dynamics and energy storage in C. regalis during their period of juvenile estuarine residency. Phospholipid and cholesterol exhibited moderate but variable (8·1-40·0 and 1·3-21·5 mg g(-1) , respectively) concentrations across the entire juvenile period and were the predominant lipid classes in juveniles <100 mm L(S) , while wax ester concentrations were low (c. 1 mg g(-1) ) and exhibited the least amount of variability among lipid classes. Triacylglycerols (TAG) and free fatty acids (FFA) exhibited similar dynamics, with relatively low concentrations (<15 mg g(-1) ) in individuals ≤100 mm L(S) . In larger juveniles both TAG and FFA concentrations generally increased rapidly, though there was considerable variability in both measures (0·0-199·7 and 0·0-49·7 mg g(-1) , respectively). Increasing levels of lipids, primarily in the form of TAG, with size indicated an accumulation of energy reserves with growth, thus providing an indication of individual condition for larger juveniles. Separate analysis of liver, viscera and the remaining carcass indicated that liver and viscera did not represent a significant depot of TAG reserves. Analysis of samples derived from whole juvenile C. regalis thus provided an accurate estimate of energy reserves.     

Otolith elemental signatures reflect residency in coastal water masses

We examined variability in otolith chemistry of wild caught fish in relation to in situ temperature and salinity within the California Current System. Barium, magnesium, and iron from the most recent growth zone in otoliths differentiated pelagic juvenile shortbelly rockfish (Sebastes jordani) residing in water masses with distinct temperature and salinity properties from central and southern California spanning nearly 500 km of coastline. The 3-element signature also discriminated fish that resided in different water masses that were associated with mesoscale cyclonic eddy circulation in the Santa Barbara Channel. Variability in otolith chemistry reflected the spatial patterns of both horizontal gradients and vertical gradients in water mass properties related to circulation. Although we found that the concentrations of particular elements in otoliths were correlated to ambient temperature or salinity, we suggest that these parameters are more useful as an identifying signature of distinct water masses associated with unique otolith signatures rather than as factors directly affecting otolith chemistry. Other factors varying among the water masses or among the fish populations residing in the water masses may also affect otolith chemistry. We discuss how oceanographic phenomena associated with the 1997–1998 El Niño and the persistent, recirculating eddy in the Channel may have affected coastal ocean conditions and variation in otolith chemistry of fish in the study area.     

Development of Sebastes taczanowskii (Scorpaenidae) in the Sea of Japan off Hokkaido with a key to species of larvae

The larval and juvenile stages of Sebastes taczanowskii (Japanese name: Ezo-mebaru) are described and illustrated based on 33 wild specimens [7.1–26.9 mm in body length (BL)] collected in the Sea of Japan, and eight specimens of reared larvae extruded from the one specimen of a captive pregnant female. Larvae were extruded between 4.3–5.0 mm BL and notochord flexion occurred 5.7–9.0 mm BL. Transformation from postflexion larvae to pelagic juveniles occurred between 13 and 17 mm BL. Preflexion and flexion larvae have a single melanophore row on the dorsal surface on the tail, and an internal line of melanistic dashes on the ventral side of the tail. Lateral pigmentation of postflexion and transforming larval body surfaces are light. Compared with other Japanese rockfish species, S. taczanowskii is shallow-bodied throughout both larval and juvenile stages. We provide an identification key to preflexion and flexion stage rockfish larvae found around the Japanese archipelago, and comparisons with other species. Larval and juvenile S. taczanowskii occurred in both near-shore and relatively offshore water around Shakotan Peninsula-Ishikari Bay, Hokkaido in June and July.     

Habitat characteristics of juvenile cowcod, <Emphasis Type="Italic">Sebastes levis</Emphasis> (Scorpaenidae), in Southern California

We characterized habitat requirements of juvenile cowcod, Sebastes levis, using information from surveys conducted aboard the manned research submersible Delta. We conducted 303 dive surveys on rocky banks and outcrops in water depths between 28 and 365 m in southern and central California, covering 483 km (963,940 m²) of seafloor. We counted 549,263 fishes from at least 134 species; 216 individuals were juvenile cowcod, S. levis, of 45 cm or less in total length (TL). Juvenile cowcod occupied depths between 52 and 330 m and demonstrated ontogenetic shifts in their habitat associations. Small fish (5–20 cm TL) lived primarily among cobbles or cobbles and small boulders. As fish grew, they moved into high-relief rock habitats, including boulder fields and rock ridges. Small cowcods were found with pygmy, Sebastes wilsoni, and swordspine, Sebastes ensifer, rockfishes. Larger juveniles often associated with juvenile bocaccio, Sebastes paucispinis, juvenile widow rockfish, Sebastes entomelas, and squarespot rockfish, Sebastes hopkinsi. Our study resulted in a characterization of seafloor habitats on a small spatial scale that is relevant to juvenile cowcod nursery areas, which is important when considering effective management strategies for this overfished species.     

Changes in mammary uptake of free fatty acids,triglyceride, cholesterol and phospholipid in relation to milk synthesis during lactation in goats

Uptake of free fatty acids (FFA), triglycerides (TG), cholesterol (CHOL) and phospholipids (PL) was measured in both mammary glands of dairy goats during lactation. Arterial concentrations of TG, CHOL and PL as well as arterio-venous difference (AV) and extraction rate (E) for TG were highest in goats with the highest dietary feed intake. AV were linearly related to arterial concentrations for the four lipid classes, and arterial concentrations of CHOL were linearly related to output of lactose, protein and fat in milk. Arterial supply, and not mammary synthetic activity, is the main determinant of mammary FFA, TG and CHOL uptake.     

Early life history of kitsune-mebaru,sebastes vulpes (scorpaenidae), in the sea of japan

The larval and juvenile stages of kitsune-mebaru,Sebastes vulpes, based on 50 wild specimens collected in, the Sea of Japan, are described and illustrated, and some ecological aspects of the early life history (feeding, horizonal distribution and habitat shift) included. Preflexion larvae became extruded between 3.9–4.6 mm body length (BL) and notochord flexion occurred between 4.7–7.1 mm BL. Transformation from postflexion larvae to pelagic juventiles occurred between 13–17 mm BL. Compared with other rockfish species,S. vulpes is deep-bodied, throughout both larval and, juvenile stages. Larval and juvenileS. vulpes inhabit mainly coastal water surface layer (usually on the continental shelf), but do not occur offshore region (northwest of Oki Islands). Although someS. vulpes juveniles are associated with drifting seaweed, such clumps are not indispensable habitats for any stages. Surface-to-benthie migration of juveniles occurs at about 25 mm BL. Preflexion and flexion larvae feed mainly on copepod nauplii, and postflexion, transforming larvae and pelagic juveniles mainly on calanoid copepodites (Parracalanus parvus).     

Uptake and interconversion of fluorescent lipid analogs in the protozoan parasite, Perkinsus marinus, of the oyster, Crassostrea virginica

Uptake, distribution, and interconversion of fluorescent lipid analogs (phosphatidylcholine, PC; cholesteryl ester, CHE; phosphatidylethanolamine, PE; palmitic acid, C16; sphingomyelin, SM) by the two life stages, meront and prezoosporangium, of the oyster protozoan parasite, Perkinsus marinus, were investigated. Class composition of these two life stages and lipid contents in meront cells were also examined. Both meronts and prezoosporangia incorporated and modified fluorescent lipids from the medium, but their metabolic modes differ to some extent. Results revealed that among the tested analogs, neutral lipid components (CHE and C16) were incorporated to a greater degree than the phospholipids (PC, PE, and SM). HPLC analysis of meront lipids showed that while the majority of the incorporated PC, CHE, and PE remained as parent compounds, most of the incorporated C16 was in triacylglycerol (TAG) and SM was in ceramide and free fatty acids. The cellular distribution of fluorescent labels varied with lipid analogs and the extent of their metabolism by the parasite. Fluorescence distribution was primarily in cytoplasmic lipid droplets of both life stages after 24 h incubation with PC. After 24 h incubation with SM, fluorescence appeared in the membrane and cytosol. Total lipid contents in meront cultures increased during proliferation and TAG accounted for most of the increased total lipids. Since total lipid content per meront cell did not increase until the day of culture termination, the lipid increase in the meront culture was mainly a result of increased cell numbers. Both life stages contain relatively high levels of phospholipids, 53.8% in 8-day-old meronts and 39.4% in prezoosporangia. PC was the predominant phospholipid.     

Ovarian aging in two species of long-lived rockfish, Sebastes aleutianus and S. alutus

Little is known about the ovary during aging in long-lived fish with respect to follicular stages and de novo oogenesis. We examined two species of rockfish, Sebastes aleutianus (rougheye rockfish) and Sebastes alutus (Pacific ocean perch). Fish were sampled offshore of British Columbia, age was estimated by otolith annuli, and the ovaries were examined histologically. In S. aleutianus, age up to 80 yr did not markedly alter the frequency distribution of oocytes, follicles, or their total numbers. Similarly, in a larger sample of S. alutus, the abundance of oocytes and follicles showed little age trend up through 77 yr. However, fish older than 50 yr lacked the largest and smallest oocyte size classes (40-60, >80 microm) and the smallest follicle size class (200-350 microm), which results from the later seasonal developmental state of these older fish. These data provide evidence that oogenesis continues at advanced ages in these two species, in contrast with long-held assumptions about mammals. These species represent an iteroparous extreme in the spectrum of life history strategies and merit investigation to determine the mechanisms for such an extended reproductive life span.     

Multiscale structures of lipids in foods as parameters affecting fatty acid bioavailability and lipid metabolism

On a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen.     

Lipid,fatty acid and protein content of late larval to early juvenile stages of the western rock lobster,Panulirus cygnus

Lipid, fatty acid and protein content were determined individually on 7 phyllosomata, 69 clear pueruli, 286 pre-moult pueruli, and 86 juvenile western rock lobster (WRL) collected from four locations between the settlement seasons 2000 to 2006 to evaluate compositional changes during the non-feeding puerulus stage. Only the lipid content, particularly the phospholipids, decreased significantly with development. Protein declined sharply following moult to the juvenile. PL comprised between 86–94% of total lipid in all animals, and declined most between phyllosomata and clear pueruli (238.5 to 121.4 mg g^? 1 DW) (p < 0.001). Triacylglycerols were the only lipid to increase in absolute amounts with development, but declined 53% on average following moult to juvenile. This increase in TAG is likely due to the conversion of phospholipids to triacylglycerols. Monounsaturated fatty acids were the main energy form utilised during benthic development while polyunsaturated fatty acids showed a high degree of sparing. The n-3:n-6 fatty acid ratio of juveniles indicates that they may be approaching critically low levels of stored lipid energy reserves. Both protein, and lipid, declined sharply from the final puerulus phase to the juvenile confirming that a high energetic demand is required to fuel the moulting process.     

Energy allocation strategy of skipjack tuna Katsuwonus pelamis during their reproductive cycle

The lipid composition of somatic and reproductive tissues was determined for female skipjack tuna Katsuwonus pelamis caught in the western Indian Ocean between latitude 10° N and 20° S and longitude 40° and 70° E. The highest total lipid (TL) contents were in the liver and gonads, with white muscle levels approximately three‐fold lower. Three lipid classes dominated: triacylglycerols (TAG), sterol esters and wax esters (SE‐WE) and phospholipids (PL). Collectively, these accounted for between 70 and 80% of TLs. Changes in lipid concentrations were evaluated over the maturation cycle. Immature fish had the lowest gonad and liver TL levels; concentrations of TL, TAG, SE‐WE and PL accumulated from immature to mature (spawning‐capable) phase, reflecting sustained vitellogenic activity of the liver and a transfer of lipids to developing oocytes from the onset of vitellogenesis. Gonado‐somatic and hepato‐somatic indices were positively correlated with each other and positively related to TL in the gonads and liver. Fulton's condition index and lipid concentrations in muscle did not vary significantly over the maturation cycle; fat content in the main storage tissues was undepleted as the ovary developed. Hence, K. pelamis apparently supports reproduction directly from food intake over the breeding season. In the gonads, reserve lipids (SE‐WE and TAG) and sterols were related to batch fecundity but this was not the case for somatic and hepatic tissues. These results suggest that K. pelamis utilizes an income breeding strategy.     

水芹花药发育中多糖和脂滴积累规律研究

运用组织学和组织化学方法详细研究了水芹(Oenanthe javanica D.C) 花药发育过程中,造孢细胞时期、小孢子母细胞时期、四分体时期、小孢子早期、小孢子晚期、二胞花粉早期和二胞花粉晚期(成熟花粉时期)的多糖以及脂滴分布特征和变化特点.结果显示:花药作为营养物质吸收的"库",在特定的时间(二胞花粉早期)和特定的部位(二胞花粉的营养细胞)积累特定的营养物质(先出现多糖颗粒,后出现脂滴物质).通过分析不同发育阶段花药中糖类和脂类分布变化,确定水芹发育花药中营养物质的运输与转换规律.     

Triacsin C inhibits the formation of 1H NMR-visible mobile lipids and lipid bodies in HuT 78 apoptotic cells

Nuclear magnetic resonance-visible mobile lipids (ML) have been reported to accumulate during cell apoptosis in vitro and in vivo. The biogenesis, biochemical nature and structure of these lipids are still under debate. In this study, a human lymphoblastoid cell line, HuT 78, was induced to apoptosis by exposure to anti-Fas monoclonal antibodies (alpha-Fas mAb) followed by incubation for different time intervals (1-24 h, hypodiploid cell fraction, H, varying from 1% to over 60%) either in the presence or in the absence of 5.0 microM Triacsin C (TRC), specific inhibitor of long-chain acyl-CoA synthetase (ACS). The increase of ML in apoptotic cells correlated linearly with H and was associated with: (a) accumulation of intracellular lipid bodies, detected by confocal laser scanning microscopy in lipophilic dye-stained cells; (b) increases, detected by thin-layer chromatography in total lipid extracts, in the relative abundance of triacylglycerides (TAG) and cholesteryl esters (CE), with corresponding decreases of phospholipids (PL). TRC completely abolished both ML and lipid body formation in anti-Fas-treated apoptotic cells, with concomitant reversion of TAG, CE and PL to control levels, but did not alter cell viability nor did it inhibit apoptosis. ML signals detected during anti-Fas-induced apoptosis therefore appear to originate from neutral lipids assembled in intracellular lipid bodies, synthesised from cellular acyl-CoA pools.     

Energetics of early development in the viviparous yellowtail rockfish

Total mean gestation period of all female yellowtail rockfish Sebastes flavidus , from fertilization to parturition, was 29.2 days. Hatching occurred 23 days after fertilization, followed by 6 days of larval incubation. Eggs varied in dry mass and energy content with lipid concentrations contributing the greatest amount of energy per egg. The endogenous energy of the yolk and oil globule declined throughout gestation resulting in limited yolk and oil reserves at parturition.     

Effects of food restriction across stages of juvenile and early adult development on body weight,survival and adult life history

Organisms have to allocate limited resources among multiple life‐history traits, which can result in physiological trade‐offs, and variation in environmental conditions experienced during ontogeny can influence reproduction later in life. Food restriction may lead to an adaptive reallocation of the limited resources among traits as a phenotypically plastic adjustment, or it can act as an overall constraint with detrimental effects throughout reproductive life. In this study, we investigated experimentally the effects of food restriction during different stages of the juvenile and early adult development on body weight, survival and reproductive success in females and males of the European earwig Forficula auricularia. Individuals either received limited or unlimited access to food across three different stages of development (fully crossed) allowing us to identify sensitive periods during development and to test both additive and interactive effects of food limitation across stages on development and reproduction. Food restriction during the early and late juvenile stage had additive negative effects on juvenile survival and adult body weight. With regard to reproductive success of females which produce up to two clutches in their lifetime, restriction specifically in the late juvenile stage led to smaller first and second clutch size, lower probability of second clutch production and reduced hatching success in the second clutch. Reproductive success of females was not significantly affected when their male mates experienced food restriction during their development. Our findings in general support the ‘silver‐spoon’ hypothesis in that food restriction during juvenile development poses constraints on development and reproduction throughout life.