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1.
Hirosuke  OKU  Hideyuki  YAMASHIRO  Kyoko  ONAGA 《Fisheries Science》2003,69(3):625-631
ABSTRACT:     Glucose has been implicated in functioning as a form of carbon translocated from symbiont zooxanthellae to the host coral cell. The present paper describes the lipid biosynthesis from [14C]-glucose in the coral tissue. To study the incorporation of [14C]-glucose into lipids, the branch tips of the coral Montipora digitata were incubated with [14C]-glucose or another radiolabeled substrates. The lipid biosynthesis from [14C]-glucose was dependent on light, and was decreased by dark conditions or by photosystem II inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Of the lipid classes, the light dependency was more pronounced with the biosynthesis of triacylglycerols (TG) and wax compared with phospholipids. Examination of [14C]-label distribution in the glycerolipids suggested that [14C]-glucose supplied mainly the fatty acid moiety of newly synthesized TG, while [14C]-glucose provided evenly the fatty acid moiety and the glycerol skeleton of phospholipids. The comparison of [14C]-labeling of lipid from host coral tissue and symbiont zooxanthellae suggested that [14C]-glucose entered the coral cell and was processed in parallel in the zooxanthellae and host cells. Furthermore, the coral cells used various [14C]-labeled sugars for lipid synthesis with similar lipid labeling profile as was the case for glucose. The current study thus supports the view that the low-molecular-weight compound, sugars and amino acids, once translocated from zooxanthellae to host cell were metabolized toward lipogenesis as well as glycerol.  相似文献   

2.
Total lipids, lipid classes, fatty acids and vitamin E contents were measured in ovary, liver, dark muscle, white muscle and mesenteric perigonadal fat in four maturational stages of Atlantic female northern buefin tuna (Thunnus thynnus thynnus L.) during migration to Mediterranean spawning grounds through the Strait of Gibraltar. Ovary lipid content increased significantly by 37.6-fold from inmature to spawning stage, accumulating large quantities of steryl/wax esters, whereas the ratio of mesenteric perigonadal fat (primarily triacylglycerols) weight to ovary weight decreased linearly throughout maturation. In contrast, liver, dark red and white muscles lipid content did not show a major depletion during maturation compared to that of perigonadal fat. The fatty acid composition of ovary from bluefin tuna showed that docosahexaenoic acid (DHA; 22:6n-3) was the most abundant fatty acid and DHA: EPA: AA and DHA: EPA ratios were 19.3/4.3/1 and 4.5/1, respectively. Neutral lipids predominated over polar lipids (2-3:1) in ovary and triacylglycerol and steryl/wax ester were major lipid classes. In general, fatty acid composition of most tissues examined were similar to each other but, in contrast, the fatty acid profile of perigonadal fat was rich in monoenes such as 18:1n-9, 20:1n-9 and 22:1n-11, and DHA decreased significantly at spawning stage. The total lipid balance suggested for the disappearance of lipid from perigonadal fat depots and, to a lesser degree, from muscle and liver depots, reflected lipid utilization for gonadal development on the one hand and non-gonadal metabolism in the other. The former included lipid transferred to the gonad and lipid catabolized to provide metabolic energy for the biosynthesis of gonadal constituents and the later was likely to be lipid catabolism to provide energy for swimming during spawning migration. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

3.
Lipid composition of the mantle and digestive gland of Octopus vulgaris that were not fed for 27 days were determined. Every 3 days, three octopuses were killed and samples of the mantle and the digestive gland (DG) were taken, in order to determine total lipids as well as lipid classes and fatty acids. Composition in total lipids (TL) for the mantle was similar until day 21, then decreased and remained similar until the end of the experiment. Composition in total lipids for the DG decreased significantly after 3 days, then remained similar until day 21, and then decreased until the end of the experiment. As for the lipid classes, in the DG the main components were triglycerides and sterol esters. Sterol esters suffered strong reductions after 10 days of starvation, while triglycerides remained similar until day 21 and then decreased until the end of the experiment. Cholesterol decreased gradually throughout the experimental period. For polar lipids, phosphatidylcholine and phosphatidylethanolamine increased during the first 3 days and then decreased throughout the experiment. In the mantle, the only neutral classes that decrease were triacylglycerols and sterol esters, while no polar lipid classes decreased in this organ. It was noticeable the decrease in almost all fatty acids in the DG after 3 days of starvation, while in the mantle there were no differences in fatty acid concentrations during the experiment.  相似文献   

4.
Total lipid content, total lipid fatty acids, lipid classes and their fatty acid compositions were studied in eggs of gilthead sea bream from two different broodstocks. The two broodstock diets used had the same total lipid content, but differed with respect to their fatty acid levels. The lipid class composition of eggs from different origins was not significantly different. The predominant polar lipids were phosphatidylcholine, phosphatidylethanolamine and sphingomyelin, and the main neutral lipid classes were cholesterol esters and triacylglycerols. The fatty acid composition of total lipids and main lipid classes in the two groups of eggs showed marked differences, reflecting the influence of fatty acid levels in the broodstock diets.  相似文献   

5.
Lipids and essential fatty acids are determinants of the reproductive process in marine fish, affecting fecundity, egg quality, hatching performance, pigmentation and larval malformation. We have analyzed and characterized the lipids of eggs and unfed larvae of two wild caught scombroid fish, the Atlantic northern bluefin tuna (Thunnus thynnus) and Atlantic bonito (Sarda sarda). Dry matter and total lipid contents, polar and neutral lipid classes and total lipid fatty acid contents were determined in the eggs of bluefin tuna and eggs and unfed larvae during the development of Atlantic bonito. Bluefin tuna eggs had slightly but significantly more dry mass than bonito eggs but very similar lipid content. However, bluefin tuna eggs presented a higher polar lipid content due to increased proportions of phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol (PI). Bonito eggs and larvae showed increasing dry mass and decreasing lipid content with development. The proportion of polar lipids increased due to increased PE, PS and PI, whereas choline-containing polar lipids (phosphatidylcholine and sphingomyelin) remained relatively constant. Free cholesterol also increased, whereas the levels of other neutral lipids, especially triacylglycerol and steryl ester fractions, decreased, presumably due to utilization for energy to drive development. Bluefin tuna eggs had higher levels of n − 3 and n − 6 highly unsaturated fatty acids due to higher docosahexaenoic and arachidonic acid contents, respectively, than bonito eggs. The results are discussed in relation to the lipid and fatty acid requirements of larval scombroid fish in comparison to those of other larval marine finfish species under culture conditions.  相似文献   

6.
The lipid classes and the fatty acid (FA) compositions of the zooxanthellae, the host tissue, and intact coral were determined for the first time in a soft coral, Sinularia sp. The contents of monoalkyldiacylglycerol (MADAG), triacylglycerol, and polar lipids differed significantly between the zooxanthellae and the host fractions. The zooxanthellae were rich in polar lipids, whereas neutral lipids were concentrated in the host. MADAG comprised 35% of the host lipids and was practically absent in zooxanthellae. Hence, MADAG is only synthesized in animal tissues and serves as a biomarker for the host in the host–zooxanthellae association of these soft corals. Similar to the zooxanthellae of reef-building corals, the main FA in the zooxanthellae of Sinularia sp. were 18:4n-3, 20:5n-3, and 22:6n-3. In addition, 16:3n-4 and 16:4n-1 (8.9% in total) were found in these zooxanthellae. The ratios of 16:3n-4, 16:4n-1, 18:4n-3, 20:5n-3, and 22:6n-3 in the zooxanthellae to those in the host tissue were 4.2, 11.2, 10.1, 11.0, and 9.1, respectively. The proportions of some FA and lipid classes in the intact coral and its fractions showed that zooxanthellate lipids comprised 36 ± 15% of the total lipids in Sinularia sp. Two tetracosapolyenoic acids (24:5n-6 and 24:6n-3) are proposed as a biomarkers of the animal tissue and indicators of the purity of the zooxanthellae fractions from soft corals.  相似文献   

7.
Dietary supplementation of phospholipids seems to be extremely important to promote growth and survival in fish larvae. Several studies also suggest the importance of n-3 highly unsaturated fatty acids (HUFA) rich phospholipids to further enhance larval performance. In the present study, four different diets were formulated in order to compare the effect of total dietary polar lipid contents, of soya bean lecithin supplementation and of feeding n-3 HUFA in the form of neutral or polar lipids on ingestion and incorporation of labelled fatty acids in gilthead seabream larvae. These diets were prepared including radiolabelled fatty acids from palmitoyl phosphatidylcholine, glycerol trioleate, free oleic acid (FOA) and free eicosapentaenoic acid (FEPA) and were fed to 25 day-old larvae. The results of these experiments showed that the elevation of the dietary polar lipid levels significantly improved microdiet ingestion, regardless of the origins of the polar lipids. This effect caused an improved incorporation of phosphatidylcholine fatty acids to the larval polar and total lipids (TL) as the dietary polar lipids increased. Nevertheless, a better incorporation of fatty acids from dietary polar lipids in comparison with that of fatty acids from dietary triglycerides into larval lipids was found in gilthead seabream, whereas a better utilization of dietary triglycerides fatty acids than dietary free fatty acids could also be observed. Besides, the presence of n-3 HUFA rich neutral lipids (NL) significanlty increased the absorption efficiency of labelled oleic acid from dietary triglycerides, but the presence of n-3 HUFA rich polar lipids, particularly improved the incorporation of FEPA. This fatty acid was preferentially incorporated into larval polar lipids in comparison with FOA.  相似文献   

8.
Western rock lobster, Panulirus cygnus, phyllosoma were grown from hatching to stage IV. Larvae were fed with Artemia enriched with a (i) base enrichment (Base) containing 520 g kg?1 squid oil or tailor made enrichments in which oils high in polyunsaturated fatty acid (PUFA) have been added at the expense of squid oil. These treatments were (ii) base enrichment supplemented with docosahexaenoic acid (DHA) rich oil, (iii) base enrichment supplemented with arachidonic acid (AA) rich oil, or (iv) base enrichment supplemented with DHA and AA (D + A) rich oils. Total survival of phyllosoma to stage IV was high, with no significant difference between treatments (range 12.3–17.5%). By stage IV, the larvae fed the DHA or AA enriched Artemia were significantly larger (3.33 mm length) than larvae fed the Base or D + A enriched Artemia (3.18–3.24 mm length). Phyllosoma were sampled at stages II and III for biochemical analysis. The major lipid class (LC) in all phyllosoma was polar lipid (PL) (88.9–92.4%), followed by sterol (ST) (6.2–9.7%). Triacylglycerol (TAG), free fatty acid (FFA) and hydrocarbon/wax ester were minor components (≤1%) in all phyllosoma samples. In contrast, the major LC in all enrichments and enriched Artemia was TAG (76.3–85.1% and 53.4–60.2%, respectively), followed by PL (11.4–14.8% and 30.6–38.1% respectively). The main fatty acids (FA) in phyllosoma were 16:0, 18:1n‐9, 18:1n‐7, 18:0, AA, eicosapentaenoic acid (EPA) and DHA. Addition of AA, and to a lesser extent DHA, to enrichments resulted in increased levels of those FA in Artemia and phyllosoma compared with the Base enrichment. This was particularly evident for stage III larvae. Comparatively, elevated growth for phyllosoma to stage IV was achieved with DHA and AA enriched diets. Our findings highlight the importance of lipids and in particular essential long‐chain PUFA, as nutritional components for phyllosoma diets.  相似文献   

9.
The total lipid profile including the fatty acid composition and amino acid composition in eggs of Hilsa (Tenualosa) ilisha was studied in comparison with its muscle tissue. The eggs contained 30.4% lipid (on dry basis), which was 1.2 times higher than that of the muscle tissue lipid. The major portion of the egg lipid was composed of wax ester (about 47.6%) followed by triacylglycerol (TAG), phospholipid (PL), and cholesterol. The muscle tissue lipid contained TAG as the major fraction (41.8 ± 1.48%). Total amount of polyunsaturated fatty acids (PUFAs) was about 43 ± 0.05% and 32.4 ± 0.24% in egg PL and body tissue PL fractions, respectively. Among fatty alcohols of egg wax ester, 16:0 alcohol is predominant (56.4 ± 3.02%). Both the egg and muscle tissues are rich in all essential amino acids. The results indicate that muscle and eggs from Hilsa are rich in essential amino acids, PUFA, and phospholipids which are essential for human health and membrane development.  相似文献   

10.
Against a background of decreasing availability of fish oils for use in aquaculture, the present study was undertaken to examine whether a wax ester-rich oil derived from the calanoid copepod Calanus finmarchicus, could be used effectively by Atlantic salmon when supplied in their diet. Individually tagged Atlantic salmon of initial weight around 500 g were divided into replicate tanks of two dietary groups and fed either a fish oil supplemented diet, or an experimental diet coated with Calanus oil. Wax esters accounted for 37.5% of the lipids in the Calanus oil diet but were absent from the fish oil diet in which triacylglycerols (TAG) were the major lipid class. Over the feeding period (140 days) the salmon fed fish oil displayed a greater increase in length, but there was no significant difference between the two groups in weight gained. The specific growth rates (0.75) and the feed conversion ratio of fish fed the two diets were similar throughout the study. No differences were observed in the apparent digestibility coefficients (ADC) of fish fed Calanus oil or fish oil. The ADC of fatty acids decreased with chain length and increased with unsaturation. Long-chain alcohol utilization showed a similar tendency although there was a notable difference in that saturated long-chain alcohols were utilized better than the comparable fatty acid homologue. In fecal lipid of fish fed Calanus oil, the content of 16:0 alcohol decreased in both the free long-chain alcohol and wax ester fractions, while the corresponding fatty acid increased in the feces of both dietary groups of fish. In contrast, the proportion of the 22:1n−11 alcohol increased in both fecal wax esters and free long-chain alcohol fractions whereas 22:1n−11 fatty acid displayed no accumulation. The observed patterns of fatty acid and long-chain alcohol compositions in fecal lipid compared to those of the initial dietary lipid are consistent with the digestive lipases of salmon preferentially hydrolyzing esters containing polyunsaturated fatty acid (PUFA) moieties. The wax esters of Calanus oil contained substantial amounts of the n−3 PUFA, 20:5n−3 and 22:6n−3, that were effectively deposited in muscle and liver tissues. No major differences were seen in either lipid content/lipid classes or in gross fatty acid composition of these tissues between the two dietary groups. It is concluded that that Atlantic salmon in seawater can effectively utilize diets in which a major lipid component is derived from zooplankton rich in wax ester without any detrimental change in growth or body lipid composition. This finding gives support to the use of lipid from zooplankton from high latitudes as an alternative or as a supplement to fish oil and a provider of long-chain n−3 PUFA in diets for use in salmon aquaculture.  相似文献   

11.
Greenshell? mussel (GSM, Perna canaliculus) is New Zealand's most important aquaculture species. This study looked at changes in the proximate composition, lipid class and fatty acid profile of male and female market ready mussels over a year from April 2016 through to March 2017. There were differences over the season as well as differences between male and female mussels. Winter GSM had lower lipid, carbohydrate and protein concentrations than other seasons. Female mussels had a higher lipid (on average 1.8 ± 0.5 g/100 g ww) and carbohydrate (on average 5.0 ± 1.1 g/100 g ww) compared with the males (lipid, 1.5 ± 0.4 g/100 g ww and carbohydrate 4.5 ± 1.2 g/100 g ww). The major differences observed between seasons in the omega 3 and fatty acids content of the GSM were driven by the fat content, with the highest fat content found in female mussels in the spring prior to spawning. The majority of lipids found in mussels are polar lipids. Overall, this study provides the most comprehensive data on the composition and the lipid content of GSM to date and provides solid base‐line data as the New Zealand GSM industry continues to improve their production procedures. The enhanced nutritional payload of mussels harvested outside of winter (particularly female mussels in spring) could drive a differentiated higher value mussel product.  相似文献   

12.
The effects of culture temperature and food deprivation on lipid class and fatty acid composition of adult male Litopenaeus vannamei (Boone) were investigated. Shrimp were maintained in recirculating seawater systems at temperatures of 26 and 32°C and fed 75% dry commercial feed and 25% fresh‐frozen squid for 42 days. Additionally, groups of fed and non‐fed shrimp were maintained at 26°C for 17 days. In shrimp fed at either 26 or 32°C, polar lipids were the main constituents of total identified lipid classes in muscle tissue (66–71%), while neutral lipids were more abundant in hepatopancreas (82–88%). Higher levels of triglycerides were observed in lipids of shrimp hepatopancreas kept at 32°C, but no other lipid class was affected by temperature. A significantly higher proportion of 22:6n‐3 was consistent in muscle and hepatopancreas polar and neutral lipids of shrimp maintained at 26°C. In response to food deprivation, the amount of polar lipids, but not neutral lipids, was reduced by approximately 28% in muscle tissue, whereas all lipid reserves were almost depleted in the hepatopancreas. The variable consumption of some individual fatty acids was observed in polar and neutral lipids of both tissues.  相似文献   

13.
Protein, lipid and fatty acid concentrations in plasma of eight male and eight female six year old captive striped bass (Morone saxatilis) were monitored monthly over the course of two reproductive cycles as part of an effort to investigate the time course of lipid class mobilization and subsequent deposition in gonads. Total protein levels (44.2 ± 0.67 mg ml–1, range 20.6–86.4) showed seasonal fluctuation, but did not vary with sex. Total lipid concentrations in the plasma of both males (17.7 ± 0.61 mg ml–1) and females (14.1 ± 0.64 mg ml–1) showed seasonal fluctuations with the lowest levels in late Spring during spawning. Plasma lipids in females were significantly (p < 0.0001) lower than those of the males except during early ovarian secondary growth. Analysis of the lipid class composition revealed that the decrease in plasma lipid concentrations in females prior to spawning is primarily due to a decrease of up to 50% in the phospholipid content of the plasma relative to males. Striped bass vitellogenin was found to contain approximately 20% lipid by weight with nearly 80% of the lipid being phosphatidyl choline (PC). Vitellogenin levels previously measured in these individuals were highest during the winter months and decreased in the 2 months prior to spawning. Although mature striped bass oocytes are rich in wax esters, no wax esters or fatty alcohols were found in the plasma. Analysis of the fatty acyl composition of separated lipid classes suggests that PC is the primary carrier of the essential (n=3) fatty acids 22:6 (DHA) and 20:5 (EPA) to the gonads. Fatty acid analysis of the lipids associated with vitellogenin revealed that levels of essential fatty acids were low relative to vitellogenin-borne lipids from other teleosts. The lack of detectable wax esters in plasma lipids of female striped bass suggests that these abundant lipids in mature eggs are synthesized within the oocytes.  相似文献   

14.
闽东海域银鲳亲鱼性腺发育后期脂类及脂肪酸蓄积特点   总被引：1，自引：0，他引：1  
脂肪和脂肪酸是海水鱼类早期生长发育的重要结构物质和能量来源。亲鱼的脂肪和脂肪酸储备影响其繁殖性能和早期仔鱼的发育。为了获知银鲳亲鱼性腺发育后期脂类及脂肪酸蓄积特点,本研究采用氯仿甲醇法及气相色谱法定量检测了繁殖季节闽东海域野生银鲳亲鱼不同组织的总脂肪及脂肪酸含量。结果表明:亲鱼卵巢、精巢、肝脏和肌肉的总脂肪含量差异显著。卵巢、精巢、肝脏和肌肉的总脂含量分别为:35.76%,15.11%,22.07%和22.14%(占组织干重)。极性脂肪占总脂肪的比例在精巢中最高,其次为肝脏和卵巢,在肌肉中最低。性腺从Ⅳ期发育到Ⅴ期,雌鱼卵巢总脂肪和中性脂肪含量显著增加,雄鱼肌肉极性脂肪含量显著降低。中性脂肪中卵巢的20∶5n-3(EPA,2.25~3.87 mg/g)、22∶6n-3(DHA,6.71~13.03mg/g)和高不饱和脂肪酸(HUFAs,17.20~29.64 mg/g)含量最高,极性脂肪中精巢的EPA(0.38~0.27 mg/g)和DHA(3.12~3.59 mg/g)含量最高。性腺中n-3/n-6比值显著高于肝脏和肌肉中。随着卵巢发育,DHA等必需脂肪酸在雌鱼不同组织及同一组织不同脂肪类别之间存在转移现象。研究表明,银鲳亲鱼各组织的总脂肪含量、总脂肪组成及脂肪酸绝对含量(mg/g干物质)具有组织特异性,随着性腺发育,必需脂肪酸总体上表现为由肌肉和肝脏向性腺中转移,且性腺中脂肪酸的变化主要发生在中性脂肪中。  相似文献   

15.
ABSTRACT:     The liver oils of five dominant shark species, Alopias superciliosus, Carcharhinus falciformis, C. longimanus, Prionace glauca , and Sphyrna lewini , in the Indian Ocean were studied for their lipid classes, fatty acid and triacylglycerol (TAG) molecular compositions, in order to understand and identify the inter species changes and possible utilization avenues. The livers showed 26.1–60.1% oil content regardless of the gender or species of shark. Triacylglycerol was the predominant lipid class (65.2–86.1%) in all species followed by sterol esters (2.9–12.7%), hydrocarbons (2.5–11.6%) and diacylglyceryl ethers (1.0–3.8%). The major fatty acid in total lipid and TAG was docosahexaenoic acid (C22:6n-3; DHA), which in male S. lewini was at remarkable levels (43.4%). The predominant fatty acid combinations of TAG molecules in all shark species were palmitic, DHA and oleic acids (PDO 12.5–19.9%), and palmitic, DHA and palmitic acids (PDP; 8.4–15.4%). Tridocosahexaenoin was found in considerable levels in S. lewini (male).  相似文献   

16.
Effects of a remarkably high overall lipid Tisochrysis lutea strain (T+) upon gross biochemical composition, fatty acid (FA), sterol and lipid class composition of Crassostrea gigas larvae were evaluated and compared with a normal strain of Tisochrysis lutea (T) and the diatom Chaetoceros neogracile (Cg). In a first experiment, the influence of different single diets (T, T+ and Cg) and a bispecific diet (TCg) was studied, whereas, effects of monospecific diets (T and T+) and bispecific diets (TCg and T+Cg) were evaluated in a second experiment. The strain T+ was very rich in triglycerides (TAG: 93–95% of total neutral lipids), saturated FA (45%), monounsaturated FA (31–33%) and total fatty acids (4.0–4.7 pg cell?1). Larval oyster survival and growth rate were positively correlated with 18:1n‐7 and 20:1n‐7, in storage lipids (SL), and negatively related to 14:0, 18:1n‐9, 20:1n‐9, 20:4n‐6 and trans‐22‐dehydrocholesterol in membrane lipids (ML). Surprisingly, only the essential fatty acid 20:5n‐3 in SL was correlated positively with larval survival. Correlations suggest that physiological disruption by overabundance of TAG, FFA and certain fatty acids in larvae fed T+ was largely responsible for the poor performance of these larvae. ‘High‐lipid’ strains of microalgae, without regard to qualitative lipid composition, do not always improve bivalve larval performance.  相似文献   

17.
Alternative marine resources from lower trophic levels could partly cover the rapidly increasing needs for marine proteins and oils in the future. The North Atlantic calanoid copepod, Calanus finmarchicus, has a high level of lipids rich in n‐3 fatty acids. However, these animals have wax esters as the main lipid storage component rather than triacylglycerol (TAG). Although these esters are considered difficult to digest by many fish, is it well known that juvenile Atlantic salmon (Salmo salar) feed on zooplankton species. It is therefore possible that the capacity to utilize these lipids should be well developed in salmonids. Nonetheless, salmon hydrolyse wax esters slower than TAG and absorb fatty alcohols slower than fatty acids. However, salmon have several adaptations to digest diets rich in wax esters. These includes increased feed conversion, higher production of bile and higher activity of lipolytic enzymes in the midgut. Atlantic salmon has been shown to feed and grow on diets with a medium amount of wax esters (30% of the lipid) with results comparable to fish maintained on fish oil diets. Ingestion of higher level of wax esters (50% of the lipid) cause, however, poorer lipid digestibility and growth, so that optimal utilization of wax esters in Atlantic salmon is closer to 30% than 50% of the dietary lipid.  相似文献   

18.
In this study, lipid classes and fatty acid composition were determinedin eggs of P. vannamei as a function of survival to zoeaIII stage. Spawns were reared individually to zoea III and grouped, accordingtotheir final survival to this larval stage, into spawns of high and lowsurvival.Eggs of individual spawns were analyzed for lipid and fatty acid composition ofneutral and polar lipids and the results were then grouped according tosurvivalto zoea III. The lipids within each group (high and low survival to zoea III)were pooled for the separation of phospholipids and the analysis of their fattyacid composition.Higher levels of triglycerides, carotenoids, and linoleic (18:2n-6) acid ineggs were associated with improved survival to zoea III. Linoleic acid washigher in spawns from the high survival group in both neutral and polarfractions and in most of the phospholipid classes analyzed. Docosahexanoic acid(DHA) was not related to survival to zoea, probably because its content washighenough (> 15% of total fatty acids) to satisfy embryo and early larvaldevelopment needs. A high content of eicosapentaenoic acid (EPA) was found inphosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylserine, andphosphatidylinositol compared to other phospholipid classes, suggesting aspecific role of EPA in these lipids. These results describe the specificphospholipid composition of penaeid eggs and could (potentially) be used aspredictive indicators of larval quality for research and production purposes.  相似文献   

19.
To establish the changes which occur during embryogenesis and early larval development, eggs, yolk sac larvae and swim-up larvae of pike were examined for lipid class and fatty acid composition. At a water temperature of 15.5°C, the embryonic phase was short (6 days) and characterized by a 41.3% decline in the lipid content of eggs, accompanied by large reductions in the amount of phosphatidylcholine (41.4% decrease), sterol esters and triacylglycerols (respectively a 41.2% decrease and a 58.1% decrease), but not phosphatidylethanolamine which increased markedly (35.6%). By the time of yolk sac absorption (7 to 11 days after fertilization) the larvae remained inactive and a limited utilization of lipids was observed. Yolk sac phosphatidylcholine was selectively incorporated into larval bodies while the levels of other lipid classes remained unchanged in the yolk. When the swim bladder was filled and the swimming stage was reached (11 days to 13 days af), the yolk was completely depleted and yolk phosphatidylcholine together with yolk triacylglycerols were catabolised. Yolk phosphatidylethanolamine and yolk sterol esters were partly incorporated into the body lipids. In the subsequent swim-up larval stage (13 to 15 days af), a steady decrease in lipids was observed (41.6%). Fluctuations in the levels of polyunsaturated fatty acids, monounsaturated fatty acids or saturated fatty acids examined from eggs or larvae were consistent with changes in lipid classes during pike development. During yolk sac absorption, pike incorporated yolk PUFA released on hydrolysis of phosphatidylcholine into the larval body. The results are discussed with reference to water temperature and in relation to the ontogenic and ecological context of pike development. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

20.
A laboratory experiment with larval cod fed natural zooplankton and enriched rotifers was carried out to investigate the effects of feed type on fatty acid (FA) and lipid composition. A divergence in FA composition was observed within a week of feeding on respective diets, and subsequent transfers of larvae from one feeding regime to the other also confirmed a rapid change in FA composition towards that of the newly provided feed source. The rapid change in FA composition after switching diet is in part expected to be due to the high growth and tissue turnover of cod larvae during the early life stages and provides an opportunity to assess recent feeding history by means of FA analysis. The FA contents also varied between the main analysed lipid classes, with relatively higher eicosapentaenoic acid levels in neutral lipids than in polar lipid classes. Although zooplankton contained notably more polar lipids and less neutral lipids than enriched rotifers, the relative amounts of polar and neutral lipids in larvae from respective prey groups were similar, signifying that the larval composition only partly reflects what they have been eating. Still, the FA composition of the previous diet was still discernible in larvae after 1–2 weeks of transfer to a new diet or after weaning to a formulated feed. The potential long‐term effects of these nutritional differences are discussed.  相似文献   

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