海南近海青干金枪鱼Thunnus tonggol和小头鲔Euthynnus affinis幼鱼的营养成分分析及评价

测定了采自海南陵水黎族自治县新村镇附近海域野生的体质量为132～199 g的青干金枪鱼Thunnus tonggol和体质量为311～504 g的小头鲔Euthynnus affinis幼鱼全鱼及肌肉的营养成分,分析其利用价值。结果显示,与小头鲔相比,青干金枪鱼腹脂率低,出肉率高;总蛋白含量高,有多种脂肪酸,且多不饱和脂肪酸含量较高,DHA和EPA含量丰富;鲜味氨基酸含量较高。青干金枪鱼和小头鲔均属高蛋白、高不饱和脂肪酸且鲜味氨基酸含量丰富的鱼类,蛋白含量优于黄鳍金枪鱼Thunnus albacares、蓝鳍金枪鱼Thunnus albacares和大眼金枪鱼Thunnus obesus,是一种蛋白质含量高、脂肪率低的优良营养来源。     

黄鳍金枪鱼背部肌肉的营养成分及评价

对黄鳍金枪鱼背部肌肉的营养成分进行了分析,并对其蛋白质营养价值进行了评价。结果显示,金枪鱼背部肌肉粗蛋白含量为26.2%,脂肪含量仅0.2%,是高蛋白、低脂肪的健康食品;根据1973年FAO/WHO推荐的必需氨基酸需要量模式(成人模式)对金枪鱼背部肌肉蛋白进行评价,氨基酸分为101,背部肌肉中呈味氨基酸占氨基酸总量的41.31%且含有丰富的矿物元素,金枪鱼背部肌肉是营养丰富、味道鲜美的优质原料。     

基于脂肪酸分析的太平洋黄鳍金枪鱼营养生态位研究

黄鳍金枪鱼(Thunnus albacares)是生态系统中的顶级捕食者, 是海洋生态系统能量流动及物质循环的重要一环。为研究太平洋黄鳍金枪鱼在个体发育过程中的摄食变化以及不同海域营养生态位差异, 根据 2019 年东太平洋和 2021 年中西太平洋海域金枪鱼渔船采集的黄鳍金枪鱼样本, 对其肌肉的脂肪酸组成及特征进行了分析研究。结果显示, 黄鳍金枪鱼肌肉检测出 34 种脂肪酸, 包括 16 种饱和脂肪酸(SFA), 8 种单不饱和脂肪酸(MUFA), 10 种多不饱和脂肪酸(PUFA)。黄鳍金枪鱼肌肉脂肪酸中 SFA 含量与 PUFA 含量呈负相关, MUFA 含量与 PUFA 含量呈正相关。SFA 含量与叉长呈显著负相关, MUFA、PUFA 含量与叉长呈显著正相关。中西太平洋和东太平洋黄鳍金枪鱼肌肉脂肪酸含量存在差异, 两海域之间脂肪酸组成平均不相似性为 18.85%, 主要差异来自 n-3 系列多不饱和脂肪酸(n-3 PUFA)、SFA、PUFA、C22∶6n3 (DHA)、Cl6∶0、Cl8∶1n9、MUFA、C22∶6n3/C20∶5n3 (DHA/EPA)、 C18∶0、n-6 系列多不饱和脂肪酸(n-6 PUFA)。主成分分析显示, 黄鳍金枪鱼的营养级越高, 肉食性越高, 以甲藻和硅藻为食源的生物对黄鳍金枪鱼的能量来源贡献越大。相反, 营养级越低的黄鳍金枪鱼主要摄食以细菌、陆地植物和植食性桡足类为食源的生物。主成分回归表明, 黄鳍金枪鱼随叉长增大, 其营养级增加, 肉食性提高, 食性逐渐由以甲壳类和头足类向虾和硬骨鱼等富含多种特征脂肪酸的生物转变。东太平洋黄鳍金枪鱼较中西太平洋肉食性更强, 营养级更高, 甲壳类对其能量贡献更大。     

黄条魳(Seriola aureovittata)肌肉营养组成分析与评价

为进一步认识和评价黄条(Seriola aureovittata)的营养与食用价值,本研究测定了其肌肉中的水分、蛋白质、粗脂肪、灰分、氨基酸、脂肪酸和矿物质等成分,并对其养殖及野生个体的肌肉营养成分组成进行了比较分析.结果显示,黄条肌肉中蛋白质含量较高,必需氨基酸和鲜味氨基酸含量丰富,完全符合FAO/WHO推荐的理想蛋白质标准,是一种优质蛋白供给源.根据AAS和CS分值,黄条肌肉的第一限制氨基酸为蛋氨酸,第二限制氨基酸为缬氨酸.黄条肌肉的脂肪含量高于三文鱼(Salmo salar)、金枪鱼(Thunnus thynnus)、石斑鱼(Epinephelus sp.)等,且肌肉中含有丰富的不饱和脂肪酸,不饱和脂肪酸与饱和脂肪酸比值较高,特别是EPA+DHA的含量高,具有较优的口感鲜度和较高的营养价值.另外,黄条肌肉中含有多种机体新陈代谢所需的矿物质,经常食用可促进人体新陈代谢水平.比较发现,养殖黄条较野生黄条具有相对较高的脂肪含量和较低的水分含量,比能值(EP)分别为13.44 kJ/g和8.68 kJ/g,其他营养成分无显著差异,表明养殖与野生黄条肌肉营养价值相似.综上所述,黄条肌肉蛋白质和脂肪质量较高,口感鲜美,营养成分丰富,是一种值得大力开发养殖的海产经济鱼类.     

黄条鰤(Seriola aureovittata)肌肉营养组成分析与评价叱

为进一步认识和评价黄条鰤(Seriola aureovittata)的营养与食用价值,本研究测定了其肌肉中的水分、蛋白质、粗脂肪、灰分、氨基酸、脂肪酸和矿物质等成分,并对其养殖及野生个体的肌肉营养成分组成进行了比较分析。结果显示,黄条鉚肌肉中蛋白质含量较高,必需氨基酸和鲜味氨基酸含量丰富,完全符合FAO/WHO推荐的理想蛋白质标准,是一种优质蛋白供给源。根据AAS和CS分值,黄条鉚肌肉的第一限制氨基酸为蛋氨酸,第二限制氨基酸为缬氨酸。黄条鉚肌肉的脂肪含量高于三文鱼(Salmo salar)、金枪鱼(Thunnus thynnus)、石斑鱼(Epinephelus sp.)等,且肌肉中含有丰富的不饱和脂肪酸,不饱和脂肪酸与饱和脂肪酸比值较高,特别是EPA+DHA的含量高,具有较优的口感鲜度和较高的营养价值。另外,黄条鉚肌肉中含有多种机体新陈代谢所需的矿物质,经常食用可促进人体新陈代谢水平。比较发现,养殖黄条鰤较野生黄条鉚具有相对较高的脂肪含量和较低的水分含量,比能值(EP)分别为13.44 kJ/g和8.68 kJ/g,其他营养成分无显著差异,表明养殖与野生黄条鰤肌肉营养价值相似。综上所述,黄条鉚肌肉蛋白质和脂肪质量较高,口感鲜美,营养成分丰富,是一种值得大力开发养殖的海产经济鱼类。     

金枪鱼将游上中国百姓餐桌

金枪鱼以其EPA和DHA含量在所有水产品中最高而成为世界营养学会推荐的三大营养鱼之一(注:另两种为大麻哈鱼和沙丁鱼)。众所周知,食用不饱和脂肪酸特别是EPA和DHA对防治心血管疾病等十分有益。金枪鱼生活在水深100-400米的大洋深处,其洄游范围限于盐度高的深海,较少接触到污染较严重的近海和沿岸水域,加上金枪鱼自捕捞、运输、加工至消费之前各环节要求都比较严格,完全保证其营养成分的保留。金枪鱼有多个品种类:蓝鳍金枪鱼、大目金枪鱼、黄鳍金枪鱼、长鳍金枪鱼、鲣鱼和剑鱼等。金枪鱼渔业根据捕捞渔具不同分为延绳钓渔业、围网渔业、…     

蓝鳍金枪鱼不同部位肌肉的营养与主要风味分析

为科学评价蓝鳍金枪鱼(Thunnus thynnus)不同部位肌肉营养与风味特征,对比分析了其背部和腹部肌肉的基本营养成分、氨基酸组成、脂肪酸组成和挥发性风味物质。结果显示,除灰分外,蓝鳍金枪鱼背部和腹部肌肉的水分、粗蛋白和粗脂肪含量差异显著;背部、腹部粗蛋白含量分别为24.70 g/100 g和18.61 g/100 g;背部、腹部粗脂肪含量分别为19.34 g/100 g和30.29 g/100 g。蓝鳍金枪鱼背部和腹部肌肉氨基酸总量分别达到(22.07±0.74) g/100 g和(16.57±0.47) g/100 g,差异显著(P<0.05)。必需氨基酸与氨基酸总量的比值均在40%左右,必需氨基酸与非必需氨基酸含量的比值均大于60%,接近于FAO/WHO推荐的蛋白质营养评价的理想模式,属于优质蛋白。谷氨酸的含量均最高,其次为天冬氨酸,胱氨酸含量最低。背部和腹部肌肉鲜味氨基酸占氨基酸总量的比例分别为34.93%和35.91%。背部和腹部肌肉中分别检测出24种和29种脂肪酸,各脂肪酸含量差异显著(P<0.05);饱和脂肪酸中肉豆蔻酸(C14:0)、棕榈酸(C16:0)和硬脂酸(C18:0)的含量高;单不饱和脂肪酸中油酸(C18:1)和二十碳一烯酸(C20:1)含量高;二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)总量占多不饱和脂肪酸总量的88.55%和75.13%。气相离子迁移谱可以有效区分蓝鳍金枪鱼背部和腹部肌肉,共检测到39种挥发性物质,包括醛类、酮类、醇类、酯类、酸类和烯烃及含氮、含硫化合物等;背部肌肉中2-庚酮、2-甲基噻吩、E-2-己烯-1-醇、戊酸、α-蒎烯、丙酸、丁酸丁酯、2-戊基呋喃、丁酸戊酯、二丙基二硫醚、二烯丙基二硫醚、庚酸乙酯、α-松油醇、甲基异丁酮、2-甲基丁醛-D、2-甲基丁醛-M的相对含量较腹部高;腹部肌肉中E-2-戊烯醛、N-亚硝基甲基乙基胺、甲基吡嗪、3-甲基丁醇、二甲苯、三乙胺、E-3-己烯-1-醇、4-甲基-2-戊醇、2-甲基丙酸乙酯、2-丁酮、乙酸乙酯、3-丁烯腈、2, 4, 5-三甲基噻唑的相对含量较高。综上所述,蓝鳍金枪鱼背部和腹部肌肉营养丰富、肉质鲜美,富含n-3多不饱和脂肪酸,风味各异。     

长荡湖野生中华绒螯蟹肌肉营养成分的分析与评价

为了解长荡湖野生中华绒螯蟹(Eriocheir japonica sinensis)肌肉的营养成分,采用国家标准生化测定方法检测了30只蟹肌肉样本中水分、蛋白质、脂肪、灰分、氨基酸和脂肪酸的含量。结果表明,长荡湖野生蟹肌肉的水分含量为78.26%、蛋白质含量为13.00%、脂肪含量为0.62%、灰分含量为1.91%。氨基酸检测中共测出17种氨基酸,谷氨酸含量最高,半胱氨酸含量最低,总量(TAA)为每100g含16.14 g。其中,4种鲜味氨基酸(DAA)占氨基酸总量的40.15%;7种必需氨基酸(EAA)和10种非必需氨基酸(NEAA)分别占氨基酸总量的33.84%和66.16%,必需氨基酸指数(EAAI)值为102.71,符合优质蛋白源的标准。脂肪酸检测中共测出饱和脂肪酸(SFA)5种、单不饱和脂肪酸(MUFA)5种和多不饱和脂肪酸(PUFA)7种。脂肪酸含量SFA∶MUFA∶PUFA为1∶1.2∶2.3;PUFA/SFA为2.3。长荡湖野生蟹可作为优质蛋白来源,对人体具有一定的营养补充和保健作用,同时也可作为中华绒螯蟹新品种选育的优质亲本。     

金沙江长鳍吻鮈的含肉率及其营养成分分析

试验测定了长鳍吻鮈(Rhinogobio ventralis)含肉率及其肌肉常规营养成分(蛋白质、脂肪、灰分、水分)、矿物元素(钙、磷、钠、镁、铜、锌、铁、锰、铬、硒)和氨基酸组成,并对其营养价值作了综合评定。结果表明,长鳍吻鮈含肉率为(69.51±4.91)%;肌肉(鲜样)中水分、粗蛋白、粗脂肪和灰分的含量分别为(70.14±0.72)%、(17.26±0.47)%、(11.28±0.64)%、(0.87±0.03)%;肌肉中17种常见氨基酸(除色氨酸外)总含量为(16.15±0.26)%;其中,必需氨基酸含量为(6.31±0.11)%,占氨基酸总含量的39.10%。必需氨基酸与非必需氨基酸含量的比值为64.20%。鲜味氨基酸含量为(6.27±0.11)%,占氨基酸总含量的38.83%。必需氨基酸指数为82.17。长鳍吻鮈的限制性氨基酸主要是异亮氨酸、蛋氨酸+胱氨酸、缬氨酸。10种矿物元素中,钙、磷、钠、镁4种常量元素的平均含量在296.32～3278.14μg/g,而铜、锌、铁、锰、铬、硒6种微量元素含量的平均值则在0.06～112.5μg/g;平均钙磷比为1∶2.1。     

养殖博氏鱼芒肉营养成分的分析及评价

采用国家标准方法测定湖北英山博氏(鱼芒)肉一般营养成分、氨基酸、脂肪酸和矿物质元素含量.结果表明,博氏(鱼芒)肉中水分、粗蛋白、粗脂肪和粗灰分的含量分别为75.36％±1.07％、17.90％±0.43％、5.13％±0.18％和0.98％±0.09％;18种氨基酸总量为(69.01±0.07) g/100 g(干重),其中5种鲜味氨基酸占氨基酸总量的41.70％,8种人体必需氨基酸占氨基酸总量的48.68％,必需氨基酸与非必需氨基酸比值为95.06％;粗脂肪中含24种脂肪酸,油酸含量38.41％±0.29％最高,单不饱和脂肪酸含量占脂肪酸总量的42.68％±0.10％,n-6多不饱和脂肪酸与n-3多不饱和脂肪酸的比值为1.48;矿物质元素中钾含量最高,为(1 118.51±30.67) mg/100 g(干重),微量元素中,铁、锌含量最高,分别为(1.19±0.10)和(1.18±0.05)mg/100 g(干重).与其它鱼类相比,博氏(鱼芒)肉蛋白质质量较高,氨基酸组成比例均衡,富含n-3多不饱和脂肪酸,矿物质元素含量丰富,有较高的营养价值.     

Primary structure and thermostability of bigeye tuna myoglobin in relation to those of other scombridae fish

ABSTRACT:   In the present study, the cDNA encoding myoglobin (Mb) of bigeye tuna Thunnus obesus was cloned and its amino acid sequence deduced in order to investigate the relationship between the primary structure and thermostability of scombridae fish Mb. An open reading frame of bigeye tuna Mb cDNA contained 444 nucleotides encoding 147 amino acids. The primary structure of bigeye tuna Mb was highly conserved when compared with those of bluefin tuna and yellowfin tuna Mb, the sequence identity being 95.2–100.0%. It also showed relatively high identity (82.3–89.1%) with the counterparts of scombridae fish. Myoglobin was then isolated from the dark muscle of four scombridae fish including bigeye tuna. Differential scanning calorimetry and circular dichroism measurements on these Mb revealed that the thermostability of bigeye tuna Mb was lowest and that of skipjack Katsuwonus pelamis Mb highest among the scombridae fish Mb examined. The α-helical contents of scombridae fish Mb at 10°C were in the range of 39.8–44.8%, clearly lower than that of horse Mb (55.3%), suggesting instability of fish Mb. The melting temperatures of these Mb fell in the range of 75.7–79.9°C, lower than that of horse Mb (84.2°C). These results strongly suggest the instability of fish Mb.     

Tuna and swordfish catch in the U.S. northwest Atlantic longline fishery in relation to mesoscale eddies

To analyze the effects of mesoscale eddies, sea surface temperature (SST), and gear configuration on the catch of Atlantic bluefin (Thunnus thynnus), yellowfin (Thunnus albacares), and bigeye tuna (Thunnus obesus) and swordfish (Xiphias gladius) in the U.S. northwest Atlantic longline fishery, we constructed multivariate statistical models relating these variables to the catch of the four species in 62 121 longline hauls made between 1993 and 2005. During the same 13‐year period, 103 anticyclonic eddies and 269 cyclonic eddies were detected by our algorithm in the region 30–55°N, 30–80°W. Our results show that tuna and swordfish catches were associated with different eddy structures. Bluefin tuna catch was highest in anticyclonic eddies whereas yellowfin and bigeye tuna catches were highest in cyclonic eddies. Swordfish catch was found preferentially in regions outside of eddies. Our study confirms that the common practice of targeting tuna with day sets and swordfish with night sets is effective. In addition, bluefin tuna and swordfish catches responded to most of the variables we tested in the opposite directions. Bluefin tuna catch was negatively correlated with longitude and the number of light sticks used whereas swordfish catch was positively correlated with these two variables. We argue that overfishing of bluefin tuna can be alleviated and that swordfish can be targeted more efficiently by avoiding fishing in anticyclonic eddies and in near‐shore waters and using more light sticks and fishing at night in our study area, although further studies are needed to propose a solid oceanography‐based management plan for catch selection.     

Comparison of the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye (T. obesus) tuna associated with drifting FADs in the equatorial central Pacific Ocean

We evaluated the behavior of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) associated with drifting fish aggregating devices (FADs) in the equatorial central Pacific Ocean. A total of 30 skipjack [34.5–65.0 cm in fork length (FL)], 43 yellowfin (31.6–93.5 cm FL) and 32 bigeye tuna (33.5–85.5 cm FL) were tagged with coded transmitters and released near two drifting FADs. At one of the two FADs, we successfully monitored the behavior of all three species simultaneously. Several individuals remained around the same FAD for 10 or more days. Occasional excursions from the FAD were observed for all three species, some of which occurred concurrently for multiple individuals. The detection rate was higher during the daytime than the nighttime for all the species, and the detection rate for bigeye tuna was higher than for yellowfin or skipjack tuna. The swimming depth was deeper during the daytime than nighttime for all species. The fish usually remained shallower than 100 m, but occasionally dived to around 150 m or deeper, most often for bigeye and yellowfin tuna during the daytime. The swimming depth for skipjack tuna was shallower than that for bigeye and yellowfin tuna, although the difference was not large, and is probably not sufficient to allow the selective harvest of skipjack and yellowfin tuna by the purse seine fishery. From the detection rate of the signals, bigeye tuna is considered to be more vulnerable to the FAD sets than yellowfin and skipjack tuna.     

世界主要金枪鱼捕捞产量分析

根据FA0 1950 ～ 2011年世界主要金枪鱼类渔业生产数据统计,将长鳍金枪鱼、黄鳍金枪鱼、大眼金枪鱼和鲣鱼等8种世界主要金枪鱼类每10年的产量总和按不同鱼种和海域进行了总结.结果显示,鲣鱼的累计总产量最高,其平均年产量涨幅最快;除马苏金枪鱼年平均产量有所下降,北方蓝鳍金枪鱼保持稳定外,其他主要金枪鱼类均有增长,但平均增长率最高的是青干金枪鱼.各主要渔区中以中西太平洋海域累计总产量最高,平均年产量有上升趋势,大西洋海域以中东大西洋为产量最高,印度洋海域以西印度洋为产量最高,平均增长率以印度洋海域为最高,其他海域相对持平.我国（包括台湾省）捕获累计总产量最高的是鲣鱼,为418×104 t,占世界总产量比例最高的是长鳍金枪鱼,为22.9％.我国（包括台湾省）主要金枪鱼类捕获总产量占世界总产量比例最高为东南大西洋海域,最低为东南太平洋海域.论文结合世界主要金枪鱼类以及主要捕捞海域的开发现状和我国国情,提出我国目前面临的几点困难以及发展壮大我国金枪鱼渔业的建议.     

不同规格玉筋鱼的营养分析与评价

为了解玉筋鱼(Ammodytes personatus)的营养价值,系统分析了3种不同规格玉筋鱼的基本营养成分、氨基酸组成、脂肪酸组成和无机元素组成。结果显示,样品规格越小,其水分、灰分和粗蛋白含量越高,粗脂肪含量越低。17种被检出的水解氨基酸中含量最高的4种氨基酸分别为谷氨酸、天门冬氨酸、赖氨酸和亮氨酸,并且规格越小,水解氨基酸含量和必需氨基酸含量越高;根据氨基酸评分分析结果可知,玉筋鱼的第一限制性氨基酸为缬氨酸,第二限制性氨基酸为异亮氨酸;根据化学评分可知,其第一限制性氨基酸为含硫氨基酸(蛋氨酸+半胱氨酸),第二限制性氨基酸为缬氨酸;其必需氨基酸指数分别为90.75、85.74和86.04。不同规格样品的脂肪酸组成有明显的差异,饱和脂肪酸含量由小到大分别为41.71、60.68和69.31 mg/g,单不饱和脂肪酸分别为31.81、65.03和103.91 mg/g,多不饱和脂肪酸(PUFA)分别为83.17、110.71和109.39 mg/g,并且规格越大,C20:5 n3占PUFA的比例越高,C22:6 n3占PUFA的比例越低。玉筋鱼富含人体所需的多种无机元素,常量元素中Na和K含量最高,微量元素中Fe和Zn的含量最高。研究表明,玉筋鱼是一种营养价值较高、味道鲜美的优质鱼类。     

金枪鱼延绳钓钓具的最适浸泡时间

根据2010年10月—2011年1月金枪鱼延绳钓海上调查数据,分两种起绳方式,建立每次作业每一根支绳的浸泡时间计算模型。将钓具的浸泡时间以1 h为间隔分别统计每个区间的支绳数量及大眼金枪鱼(Thunnus obesus)、黄鳍金枪鱼(Thunnus albacores)的渔获尾数,并计算其钓获率(CPUE)。结果表明:1)大眼金枪鱼和黄鳍金枪鱼的CPUE都随浸泡时间的增加呈现先增后减的趋势,这是由于饵料的诱引效果变化及渔获的丢失引起的;2)二次曲线可拟合浸泡时间与大眼金枪鱼和黄鳍金枪鱼CPUE的关系;3)大眼金枪鱼和黄鳍金枪鱼CPUE最高的浸泡时间分别为9.9 h和10.1 h。建议:1)今后在金枪鱼延绳钓作业中,保证每一根支绳在水中的浸泡时间为9.5~10.5 h,以提高捕捞效率并减少副渔获物;2)可把延绳钓钓具的浸泡时间作为有效捕捞努力量,并用于CPUE的标准化。研究结果可用于提高捕捞效率并减少副渔获物的技术方案制订,并为渔业生产和CPUE的标准化提供科学参考。     

中东太平洋金枪鱼延绳钓渔获物组成分析

根据2000年9月至2002年8月两年的中东太平洋金枪鱼延绳钓探捕调查结果,对延绳钓渔获物组成进行了初步分析。结果显示,延绳钓的主要渔获种类有肥壮金枪鱼(Thunnus obesus)和黄鳍金怆鱼(Thunnus albacares)等15种大洋性鱼类,渔获物中金枪鱼类分别占重量和尾数的76．41％和76．91％,旗鱼类占11．05％和7．83％．鲨鱼类占10．80％和12．08％,其他鱼类占1．73％和3．18％。相对重要性指标(IRI)表明,延绳钓渔业以肥壮金枪鱼和黄鳍金枪鱼为目标鱼种,其他大型中上层经济鱼类为兼捕对象。各渔获种类的渔获重量组成比例月间变化和海域变化明显。     

长江水系青鱼不同地理群体肉质差异比较

为了解长江水系青鱼不同地理群体肌肉营养品质的差异，用国标生化法测定了湖南湘江群体(XJ)、湖北石首群体(SS)、江苏邗江群体(HJ)青鱼肌肉的常规营养成分、氨基酸和脂肪酸的含量，并按FAO/WHO建议的标准进行了营养品质评价。结果显示：3个群体青鱼肌肉的水分质量分数为81.08%～82.20%,粗蛋白质质量分数为16.86%～17.94%,粗脂肪质量分数为0.46%～0.52%,粗灰分质量分数为1.26%～1.34%,3个群体间常规营养成分无显著性差异(P>0.05);在3个群体青鱼的肌肉中均检测出16种氨基酸，其中人体必需氨基酸7种，半必需氨基酸2种，非必需氨基酸7种，必需氨基酸占总氨基酸的39.24%～40.22%,鲜味氨基酸占总氨基酸的38.54%～39.37%;在脂肪酸组成和含量上，石首群体、邗江群体中均检测到18种脂肪酸，其中饱和脂肪酸9种，单不饱和脂肪酸3种，多不饱和脂肪酸6种，以上两个群体的脂肪酸组成种类均多于湘江群体，邗江群体在饱和脂肪酸总量和多不饱和脂肪酸总量上均显著高于石首群体和湘江群体(P<0.05),而在单不饱和脂肪酸总量上，3个群体间差异不显著(P...     

Metabolic biochemistry of cardiac muscle in three tuna species (bigeye, Thunnus obesus ; yellowfin, T. albacares ; and skipjack, Katsuwonus pelamis ) with divergent ambient temperature and oxygen tolerances

Bigeye tuna (Thunnus obesus) have much greater vertical mobility than yellowfin (T. albacares) and skipjack (Katsuwonus pelamis) tunas, due to an apparent greater tolerance of the changes in ambient temperature and oxygen occurring with depth. In an attempt to identify physiological processes (e.g., effects of temperature on cardiac function) responsible for these behavioral differences, we examined enzyme activities (at 12 °C, 17 °C, and 25 °C) of cardiac muscle in all three species. Contrary to our expectations, we found few differences and no clear explanatory patterns in maximum enzyme activities (V_max) or enzyme activity ratios. For example, citrate synthase (CS) activity was the same in bigeye and skipjack tunas, but 40% lower in yellowfin tuna, whereas carnitine palmotoyltransferase (CPT) activity in skipjack tuna was approximately double that in the other two species. The ratio of CPT to pyruvate kinase (PK) activity, a measure of the tissues preference for fatty acids as metabolic substrates, was the same in bigeye and yellowfin tunas, but elevated skipjack tuna. The ratios of lactate dehydrogenase (LDH) to CS activity and of PK to CS activity (anaerobic–aerobic enzyme activity ratios – taken as measures of the tissues ability to tolerate hypoxia) were both elevated in yellowfin tuna cardiac tissue relative to the other two species. We also found no differences in temperature sensitivity (Q₁₀ values) when comparing cardiac enzyme activities across species, nor effects of temperature on the substrate affinity (K_m) of LDH. In sum, our results do not suggest any clear metabolic difference in the cardiac muscle that would explain the apparent greater tolerance of bigeye tuna to acute hypoxia and ambient temperature changes or their substantially greater vertical mobility.