Lipid content and fatty acid composition of muscle,liver, ovary and eggs of captive-reared and wild silver Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> during artificial maturation

ABSTRACT:   Changes in lipid content and fatty acid composition of muscle, liver and ovary of captive-reared and wild silver Japanese eel Anguilla japonica were examined during artificial maturation induced by salmon pituitary homogenate (SPH) injections. Although the relative levels of n-3 and n-6 highly unsaturated fatty acids (HUFA) in liver and ovary were higher than in muscle in both captive and wild silver eels before SPH injection, these tended to decrease with maturation. The relative levels of n-6 HUFA in muscle, liver, ovary and eggs of wild silver eels were remarkably higher than those in captive eels. Therefore, we attempted to alter the ratio of n-6 HUFA in eggs by feeding eels a diet supplemented with linoleic acid-rich plant oil. Although the percentage of n-6 polyunsaturated fatty acids to total fatty acids in eggs of eels fed the supplemented diet was similar to wild silver eels, the percentage of n-6 HUFA remained remarkably lower than in wild silver eels. Hence, it appears that the supplemented diet affected the fatty acid composition of eggs, but did not result in much conversion of linoleic acid to its higher homologs in eels.     

野生与人工养殖牙鲆亲鱼不同组织脂肪酸的比较

为研究脂肪酸对牙鲆繁育性能的影响, 采用生物化学方法, 对野生和养殖牙鲆亲鱼肌肉、肝脏及卵中脂肪酸组成分别进行测定。结果表明: (1) 牙鲆肌肉、肝脏和卵中脂肪含量大小关系为肝脏>卵>肌肉。野生亲鱼肌肉和卵中脂肪含量显著低于养殖亲鱼(P<0.05), 肝脏脂肪含量与养殖亲鱼无显著差异; (2) 牙鲆亲鱼3种组织中均检测出21种脂肪酸。野生亲鱼肌肉中饱和脂肪酸(SFA)与养殖亲鱼无显著差异, 单不饱和脂肪酸(MUFA)显著低于养殖亲鱼(P<0.05)。肝脏和卵中SFA显著高于养殖亲鱼(P<0.05), MUFA与养殖亲鱼无显著差异; (3) 野生亲鱼肌肉、肝脏和卵中高不饱和脂肪酸(PUFA)的含量, 尤其是肝脏和卵中C20:5n-3(EPA)、C22:6n-3(DHA)的含量均显著低于养殖亲鱼(P<0.05), 但肌肉和卵中的C20:4n-6(ARA)含量明显高于养殖亲鱼(P<0.05); (4) 野生牙鲆亲鱼肌肉、肝脏和卵中n-3/n-6 PUFA及EPA/ARA显著低于养殖亲鱼(P<0.05), 肝脏中DHA/EPA显著高于养殖亲鱼(P<0.05), 但野生亲鱼肌肉和卵中的DHA/EPA与养殖亲鱼无显著差异。比较结果说明, DHA、EPA和ARA等PUFA是与牙鲆繁殖性能密切相关的重要脂肪酸。在牙鲆亲鱼养殖过程中, 除了提供牙鲆亲鱼足够的脂肪酸营养外, 也应注意各种脂肪酸, 尤其是PUFA中各种脂肪酸之间的添加比例, 从而保证亲鱼的繁殖性能及卵和仔鱼的质量。     

兴凯湖翘嘴鲌野生和养殖群体脂肪酸及相关血液指标的比较

对3龄、4龄和5龄兴凯湖翘嘴鲌(Culter alburnus)野生和养殖群体肌肉脂肪含量、脂肪酸含量以及部分血液生化指标进行了分析比较.结果表明:在兴凯湖翘嘴鲌野生与养殖群体肌肉中均检测到18种脂肪酸,以油酸、亚油酸和棕榈酸为主.野生群体肌肉饱和脂肪酸(SFA)、多不饱和脂肪酸(PUFA)、二十碳五烯酸(EPA)和二...     

Comparative fatty acid profiles of wild and farmed tropical freshwater fish rohu (<Emphasis Type="Italic">Labeo rohita</Emphasis>)

The proximate composition of the whole body and the fatty acid composition of the liver, muscle, eye and brain of wild and cultured rohu (Labeo rohita) were analyzed. The cultured species was found to have significantly (P < 0.05) higher lipid contents than its wild counterpart. The saturated (SFA) and monounsaturated (MUFA) fatty acid contents were significantly higher in the cultured species, whereas the n-6 and n-3 polyunsaturated fatty acid (PUFA) levels were higher in the wild species. Fatty acids C16:0 and C18:1 n-9 were the principal fatty acids of the SFAs and MUFAs, respectively, identified in the analyses. Docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid were the predominant PUFAs in both groups, and all three were found to be present at significantly (P < 0.05) higher levels in the wild species. Erucic acid (C22:1 n-9), which was the predominant fatty acid (30.76%) in the feed, was detected only at low levels in muscle (0.30%), liver (1.04%) and eye (1.28%) of cultured fish tissue.     

Fatty acids in muscle of wild and farmed red porgy, Pagrus pagrus

The total fat content and the fatty acids of total lipids (TL), phospholipids (PL) and triacylglycerols (TAG) were analysed in white muscle from wild and reared red porgy, Pagrus pagrus (L.). The fat percentage was higher in reared (3.03 ± 0.57%) (mean ± SE) than wild (0.65 ± 0.03%) fish. The fatty acid pattern of reared porgy TL reflected the diet's lipid. Wild red porgy showed higher levels of ω3 and ω6 polyunsaturated fatty acids (PUFA) than reared, but both the atherogenic index and the index of thrombogenicity were very low for both wild and reared red porgy. The lipid fractions showed that the PL were composed of very high levels of PUFA, especially 22:6ω3, and their composition seemed to be better regulated than the composition of TAG. TAG showed greater differences between wild and reared fish, presumably because they reflected the dietary content of lipids. PUFA were the principal component of wild red porgy TAG.     

Comparison of fatty acid contents of wild and cultured rainbow trout <Emphasis Type="Italic">Onchorhynchus mykiss</Emphasis> in Turkey

Abstract:   The total lipid content and fatty acid composition were determined in the flesh and skin of wild and cultured rainbow trout in Turkey. The effect of diet content was also investigated on cultured trout. Gas chromatography-mass spectrometry (GC-MS) was used for fatty acid analyses. Total lipid content of skin was higher than flesh in both types and when compared appreciably higher in cultured fish. The predominant fatty acid was palmitic acid (C16:0) in saturated fatty acids and oleic acid (C18:1n-9) in monounsaturated fatty acids. The amount of eicosapentaenoic acid was double in wild and docosahexaenoic acid (DHA) 1.5 times higher in cultured fish flesh. The n-3/n-6 ratio was higher in cultured fish than wild fish. The levels of palmitic, oleic, linoleic (C18:2n-6) and palmitoleic (C16:1n-7) acids were high in skin. The level of EPA was the same in skin of wild fish but 5.5 times higher in cultured fish, whereas the proportion of DHA in skin was lower for wild and 3.5 times higher in cultured fish. Wild fish had a high level of linoleic, arachidonic (C20:4n-6) and linolenic (C18:3n-3) acids. The total amount of n-3 and n-6 polyunsaturated fatty acids was higher in flesh of wild fish than cultured fish, contrary to skin of cultured fish. The data obtained demonstrated that fatty acid composition of cultured fish did not depend on that of feed.     

Comparative studies on lipid profiles and amino acid composition of wild and cultured Dojo loach Misgurnus anguillicaudatus obtained from southern Japan

The aim of this study was to determine the differences in the nutritional properties of wild and cultured loach Misgurnus anguillicaudatus obtained from southern Japan. Major parameters, such as whole-body proximate composition, lipid classes, and fatty acid and amino acid composition, were investigated. The whole-body total lipid content of cultured loach was twofold higher than that of wild loach and the proportion of neutral lipids was significantly higher in cultured loach than in wild loach. However, the polar lipid content was two- to threefold lower in cultured loach than in wild loach. Compared to the wild loach, higher contents of 20:5n-3 and 22:6n-3 were detected in cultured loach, but much lower contents of 20:4n-6. In terms of whole-body amino acid composition, wild and cultured loach showed similar profiles. In conclusion, the consumption of cultured loach will contribute to dietary n-3 highly unsaturated fatty acids intake, with a benefit to human health.     

野生与养殖黑斑蛙肌肉营养品质的比较分析

对黑斑蛙肌肉一般营养成分、氨基酸、脂肪酸和矿物元素进行测定,旨在比较分析野生与养殖黑斑蛙肌肉的营养品质。试验结果表明,养殖黑斑蛙肌肉粗蛋白与粗脂肪含量高于野生黑斑蛙,水分含量则低于野生黑斑蛙,但两者间差异不显著( P >0.05);野生与养殖黑斑蛙肌肉除谷氨酸和酪氨酸外的氨基酸含量均无显著性差异( P >0.05);野生黑斑蛙肌肉的总氨基酸、非必需氨基酸和鲜味氨基酸含量高于养殖黑斑蛙。根据氨基酸评分和化学评分结果,野生和养殖黑斑蛙肌肉中赖氨酸含量相对较高,第一限制性氨基酸均为蛋氨酸+胱氨酸,必需氨基酸指数分别为70.25和72.42。野生黑斑蛙饱和脂肪酸含量显著高于养殖黑斑蛙( P <0.05),而养殖黑斑蛙肌肉的多不饱和脂肪酸、必需脂肪酸、二十碳五烯酸、二十二碳六烯酸、n-3和n-6多不饱和脂肪酸含量均高于野生黑斑蛙( P >0.05)。野生与养殖黑斑蛙肌肉14种矿物元素中,锌、铝和硒含量有显著差异( P <0.05),重金属元素(砷、镉、铅)含量均在限量范围以内。由此可知,养殖黑斑蛙营养组成价值接近于野生黑斑蛙。     

Proximate,Fatty Acid,and Amino Acid Compositions of Fish Muscle and Egg Tissue of Hilsa (Tenualosa) ilisha

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.     

野生与养殖黄颡鱼鱼卵的营养成分比较

以贵州省铜仁锦江河漾头河段野生黄颡鱼鱼卵和同一区域内养殖黄颡鱼鱼卵为研究对象,采用常规生化方法测定了野生与养殖黄颡鱼鱼卵氨基酸组成和含量,采用气相色谱技术检测了野生与养殖黄颡鱼鱼卵脂肪酸组成和含量。氨基酸测定结果表明,野生黄颡鱼鱼卵的氨基酸总量、必需氨基酸总量、鲜味氨基酸总量显著低于养殖黄颡鱼鱼卵(P0.05),第一限制性氨基酸均为甲硫氨酸+半胱氨酸,必需氨基酸指数分别为55.60和59.12。脂肪酸测定结果表明,野生黄颡鱼鱼卵的饱和脂肪酸总量极显著高于养殖黄颡鱼鱼卵(P0.01),单不饱和脂肪酸总量二者差异不显著(P0.05),多不饱和脂肪酸总量极显著低于养殖黄颡鱼鱼卵(P0.01),但野生黄颡鱼鱼卵的二十碳五烯酸和二十二碳六烯酸的总量极显著高于养殖黄颡鱼鱼卵(P0.01),野生黄颡鱼鱼卵的n-3系列的多不饱和脂肪酸总量与n-6系列不饱和脂肪酸总量的比值(1.57)低于养殖黄颡鱼鱼卵(1.80)。     

野生与养殖光唇鱼肌肉营养组成与评价

对采自浙江省新昌县的野生(平均质量15.3g)和养殖(平均质量14.9g)光唇鱼肌肉营养组成分别进行了测定和评价。野生光唇鱼肌肉蛋白质含量为16.62%,脂肪2.66%,水分80.73%,灰分0.92%;养殖光唇鱼肌肉蛋白质含量为16.51%,脂肪2.51%,水分80.65%,灰分0.94%;野生光唇鱼的水分、蛋白质和脂肪含量均较养殖光唇鱼略高。共检测到17种氨基酸,其中必需氨基酸8种,风味氨基酸4种。野生组的氨基酸总量显著高于养殖组;必需氨基酸的总量也高于养殖组。与养殖光唇鱼相比,野生光唇鱼肌肉中苏氨酸、亮氨酸及含硫氨基酸含量较高。以氨基酸评分为标准,光唇鱼肌肉的第一限制氨基酸是赖氨酸,第二限制性氨基酸为缬氨酸;以化学评分为标准,说明光唇鱼肌肉必需氨基酸组成相对平衡且含量丰富,是一种较为平衡的优质蛋白质。共检出22种脂肪酸,光唇鱼肌肉中所含饱和脂肪酸有9种;不饱和脂肪酸共有14种,其中单不饱和脂肪酸6种,多不饱和脂肪酸8种;饱和脂肪酸中C 16:0含量最大;而不饱和脂肪酸中C 16:1和C 18:2含量最高。多不饱和脂肪酸中二十碳五烯酸(C 20:5)含量为10.20%;二十碳六烯酸(C 22:6)含量为9.18%,在淡水鱼中是较高的,是一种优质的淡水食用鱼类。     

Nutritional comparison in muscle of wild,pond and factory cultured Japanese flounder (Paralichthys olivaceus) adults

Muscle proximate composition, amino acid profiles, fatty acid compositions and selected minerals of wild, pond and factory cultured Japanese flounder adults were compared in this study to elucidate their nutritive values and dietary nutrition requirements. Wild and pond cultured Japanese flounder flesh had higher crude proteins, but crude lipid contents of factory cultured fish were 3.8~4.0 fold greater. Major amino acids in Japanese flounder were aspartic acid, glutamic acid and lysine. Wild fish had higher levels of total amino acids, essential amino acids, nonessential amino acids and half‐essential amino acids and the contents in pond cultured samples were similar. Arachidonic acids (ARA), eicosapentaenoic acids (EPA), docosahexaenoic acids (DHA), polyunsaturated fatty acids (PUFA), DHA + EPA and n–3 PUFA in wild Japanese flounder were significantly higher than that in factory cultured fish, whereas fatty acid levels were close between pond cultured and wild fish. Japanese flounder were rich in zinc, iron and selenium, but poor in copper, chromium and nickel. Results indicated wild Japanese flounder had higher nutritional value and better meat quality, but the nutritional compositions of pond cultured fish were close to wild Japanese flounder, which suggested that pond culture of Japanese flounder offers broad application prospects.     

Lipids in female northern bluefin tuna (Thunnus thynnus thynnus L.) during sexual maturation

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.     

Egg quality determinants in cod (Gadus morhua L.): egg performance and lipids in eggs from farmed and wild broodstock

Lipids and essential fatty acids, particularly the highly unsaturated fatty acids, 20:5n‐3 (eicosapentaenoic acid; EPA), 22:6n‐3 (docosahexaenoic acid; DHA) and 20:4n‐6 (arachidonic acid, AA) have been shown to be crucial determinants of marine fish reproduction directly affecting fecundity, egg quality, hatching success, larval malformation and pigmentation. In Atlantic cod (Gadus morhua L.) culture, eggs from farmed broodstock can have much lower fertilization and hatching rates than eggs from wild broodstock. The present study aimed to test the hypothesis that potential quality and performance differences between eggs from different cod broodstock would be reflected in differences in lipid and fatty acid composition. Thus eggs were obtained from three broodstock, farmed, wild/fed and wild/unfed, and lipid content, lipid class composition, fatty acid composition and pigment content were determined and related to performance parameters including fertilization rate, symmetry of cell division and survival to hatching. Eggs from farmed broodstock showed significantly lower fertilization rates, cell symmetry and survival to hatching rates than eggs from wild broodstock. There were no differences in total lipid content or the proportions of the major lipid classes between eggs from the different broodstock. However, eggs from farmed broodstock were characterized by having significantly lower levels of some quantitatively minor phospholipid classes, particularly phosphatidylinositol. There were no differences between eggs from farmed and wild broodstock in the proportions of saturated, monounsaturated and total polyunsaturated fatty acids. The DHA content was also similar. However, eggs from farmed broodstock had significantly lower levels of AA, and consequently significantly higher EPA/AA ratios than eggs from wild broodstock. Total pigment and astaxanthin levels were significantly higher in eggs from wild broodstock. Therefore, the levels of AA and phosphatidylinositol, the predominant AA‐containing lipid class, and egg pigment content were positively related to egg quality or performance parameters such as fertilization and hatching success rates, and cell symmetry.     

Nutritional evaluation of fatty acids for the open thelycum shrimp, Litopenaeus vannamei: II. Effect of dietary n-3 and n-6 polyunsaturated and highly unsaturated fatty acids on juvenile shrimp growth, survival, and fatty acid composition

This study evaluated the nutritional value of dietary n‐3 and n‐6 polyunsaturated fatty acids (PUFA) such as linoleic (LOA) and linolenic (LNA) acids, and highly unsaturated fatty acids (HUFA) such as arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids for juvenile Litopenaeus vannamei, based on their effects on growth, survival, and fatty acid composition of hepatopancreas and muscle tissue. Diets contained 5% total lipid. A basal diet contained palmitic and stearic acids each at 2.5% of diet. Five diets contained 0.5% dry weight of LOA, LNA, AA, EPA, or DHA. An additional diet evaluated HUFA in combination by supplementing at 0.5% of diet, a mixture of n‐3 HUFA. All HUFA showed higher nutritional value than PUFA for shrimp and produced significantly (P < 0.05) higher final weight, weight gain, and total lipid in shrimp muscle. Fatty acid profiles of shrimp tissues reflected the composition of the dietary lipids. In general, saturated fatty acids were more abundant in the neutral factions, while PUFA and HUFA were more abundant in the polar fractions of tissues. Under these experimental conditions, HUFA had much greater nutritional value than PUFA for juvenile L. vannamei; moreover, dietary requirements for PUFA were not demonstrated.     

Fatty acid compositions in muscles of wild and cultured ocellate puffer Takifugu rubripes

Lipid contents and fatty acid compositions were compared among 110 muscle samples of Japanese wild, Japanese cultured, and Chinese cultured ocellate puffer Takifugu rubripes. The effects of diet on muscle lipids in cultured ocellate puffer were also investigated. There was no noticeable difference between the wild and cultured fish with regard to the lipid content, but there were significant differences in the fatty acid composition ratio such as C16:0, C16:1n-7, and C20:4n-6. Moreover, the percentages of the fatty acids C18:2n-6 and C22:5n-3 were correlated with those in the diet. These results suggest that the muscle lipid content was not affected by diet, whereas fatty acid composition was affected. There were significant differences in fatty acid composition among Japanese wild fish, Japanese cultured fish, and Chinese cultured fish. The results suggest that the fatty acid composition is applicable as a tool to distinguish between wild and cultured ocellate puffer as well as those cultured in Japan and China.     

Influences of dietary fatty acid profile on growth, body composition and blood chemistry in juvenile fat cod (Hexagrammos otakii Jordan et Starks)

This study was conducted to investigate the influence of dietary lipid source and n‐3 highly unsaturated fatty acids (n‐3 HUFA) level on growth, body composition and blood chemistry of juvenile fat cod. Triplicate groups of fish (13.2 ± 0.54 g) were fed the diets containing different n‐3 HUFA levels (0–30 g kg^?1) adjusted by either lauric acid or different proportions of corn oil, linseed oil and squid liver oil at 100 g kg^?1 of total lipid level. Survival was not affected by dietary fatty acids composition. Weight gain, feed efficiency and protein efficiency ratio (PER) of fish fed the diets containing squid liver oil were significantly (P < 0.05) higher than those fed the diets containing lauric acid, corn oil or linseed oil as the sole lipid source. Weight gain, feed efficiency and PER of fish increased with increasing dietary n‐3 HUFA level up to 12–16 g kg^?1, but the values decreased in fish fed the diet containing 30 g kg^?1 n‐3 HUFA. The result of second‐order polynomial regression showed that the maximum weight gain and feed efficiency could be attained at 17 g kg^?1 n‐3 HUFA. Plasma protein, glucose and cholesterol contents were not affected by dietary fatty acids composition. However, plasma triglyceride content in fish fed the diet containing lauric acid as the sole lipid source was significantly (P < 0.05) lower than that of fish fed the other diets. Lipid content of fish fed the diets containing each of lauric acid or corn oil was lower than that of fish fed the diets containing linseed oil or squid liver oil only. Fatty acid composition of polar and neutral lipid fractions in the whole body of fat cod fed the diets containing various levels of n‐3 HUFA were reflected by dietary fatty acids compositions. The contents of n‐3 HUFA in polar and neutral lipids of fish increased with an increase in dietary n‐3 HUFA level. These results indicate that dietary n‐3 HUFA are essential and the diet containing 12–17 g kg^?1 n‐3 HUFA is optimal for growth and efficient feed utilization of juvenile fat cod, however, excessive n‐3 HUFA supplement may impair the growth of fish.     

闽东海域银鲳亲鱼性腺发育后期脂类及脂肪酸蓄积特点

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。     

养殖和野生亚东鲑机体成分比较分析

亚东鲑(Salmo trutta fario)是鲑属鱼类在青藏高原仅有的鱼类种群,是亚东地区全国农产品地理标志产品。本研究对西藏亚东地区野生和养殖亚东鲑的常规营养成分及各组织氨基酸和脂肪酸组成进行分析,旨在比较野生和养殖亚东鲑营养成分的异同,为养殖亚东鲑的品质评价和饲料配方的完善提供参考信息。实验采集亚东河中野生亚东鲑和亚东渔业产业园中使用配合饲料养殖的亚东鲑各10尾用于相关成分分析,每尾为一个独立样本。结果显示,野生组肥满度显著低于养殖组,而全鱼水分和灰分显著高于养殖组。全鱼粗蛋白、粗脂肪以及肝脏常规成分在野生组和养殖组间无显著差异。野生组肌肉粗脂肪显著低于养殖组,而水分含量显著高于养殖组。野生组全鱼必需氨基酸总量显著高于养殖组,且野生组肌肉中苏氨酸、缬氨酸、苯丙氨酸、赖氨酸和甘氨酸含量显著高于养殖组。野生组全鱼、肌肉和肝脏中饱和脂肪酸、n-3多不饱和脂肪酸(n-3 PUFA)总量、EPA、C20:4n-6以及肌肉中DHA含量高于养殖组,而全鱼和组织中单不饱和脂肪酸和n-6 PUFA总量低于养殖组。综上所述,目前养殖亚东鲑和野生亚东鲑在机体成分上存在较大差异。由于养殖鱼类体成分很大程度上反映了饲料组成,因此,亚东鲑养殖中饲料营养组成可能有待进一步优化。     

Temperature-dependent lipid levels and components in polar and temperate eelpout (Zoarcidae)

Total lipid content, lipid classes and fatty acid composition were analysed in tissues from two eelpout species fed on the same diet, the Antarctic Pachycara brachycephalum and the temperate Zoarces viviparus, with the aim of determining the role of lipids in fishes from different thermal habitats. The lipid content increased with decreasing temperature in the liver of both species, suggesting enhanced lipid storage under cold conditions. In P. brachycephalum, lipid composition in the liver and muscle was strongly dominated by triacylglycerols between 0 and 6°C. In contrast, in the temperate species, lipid class composition changed with changes in the temperature. When acclimatized to 4 and 6°C Z. viviparus not only displayed a shift to lipid anabolism and pronounced lipid storage, as indicated by high triacylglycerol levels, but also a shift to patterns of cold adaptation, as reflected by an increased content of polyunsaturated fatty acids in the lipid extract. Unsaturated fatty acids were also abundant in the Antarctic eelpout, but when compared to Z. viviparus at the same temperatures, the latter had significantly higher ratios of polyunsaturated to saturated fatty acid levels, whereas the Antarctic eelpout showed significantly higher ratios of monounsaturated to saturated fatty acid levels. High δ-¹⁵N values of the Antarctic eelpout reflect the high trophic level of this scavenger in the Weddell Sea food web. Stable carbon values suggest that lipid-enriched prey forms a major part of its diet. The strategy to accumulate storage lipids in the cold is interpreted to be adaptive behaviour at colder temperatures and during periods of irregular, pulsed food supply.