氮饥饿与磷饥饿促使缺刻缘绿藻花生四烯酸含量增加的比较

以富含花生四烯酸(AA)的缺刻缘绿藻H4301为研究对象,探讨了不同光照强度条件下氮饥饿与磷饥饿对藻生物量、AA及脂肪酸含量变化的影响。发现氮饥饿与磷饥饿均降低了藻类的生长速率与生物量,当在60 μmol photons/(m²·s)的低光照强度下,磷饥饿时的藻类平均生长速率最低［0.025 g/(d·L)］,不足BG-11完全培养基中该藻生长速率的一半;氮饥饿与磷饥饿均能提高藻细胞总脂肪酸及AA的含量,但在低光照强度下磷饥饿的促进效果比较差;无论是完全培养基中还是饥饿处理时,200 μmol photons/(m²·s)的高光照强度都不利于藻细胞AA及多不饱和脂肪酸的合成与积累;随着饥饿时间的不断持续,AA占总脂肪酸的百分含量逐渐增加,而亚油酸的百分含量逐渐降低,但在磷饥饿时,油酸的百分含量也增加,特别在高光照强度下,以油酸为主的单不饱和脂肪酸含量在第27天时占细胞干重的5.28%,以致AA含量的增加没有氮饥饿时的显著。从脂肪酸成分的变化来分析,该藻在氮或磷饥饿过程中主要是从亚油酸到γ-亚麻酸再到20∶3ω6这个途径来合成并积累AA,其中Δ6去饱和酶是限速酶,而ω3去饱和酶催化步骤受饥饿处理的负调控对确保AA的合成与积累有较大的积极作用。氮饥饿使藻细胞蛋白质合成受阻以及磷饥饿使核酸合成、糖类与能量代谢产生障碍,从而阻止藻类的生长并迫使细胞代谢流转向不含氮和磷的脂肪酸合成代谢,以提高藻细胞总脂肪酸及AA含量。     

氮磷浓度对筒柱藻生长及理化成分的影响

本文探索了不同氮磷浓度对筒柱藻生长及其理化成分的影响.结果表明:筒柱藻生长的适宜氮浓度和磷浓度分别为440 μM、9.08 μM,而在氮浓度为880μM或磷浓度为72.64 μM时,叶绿素含量、胞内蛋白、胞内多糖及胞外多糖的含量达到最大值.     

短期饥饿对大鳍鱯生化组成、氨基酸和脂肪酸组成的影响

在水温(21±1)℃条件下,研究了大鳍鱯(Mystus macropterus)在短期饥饿胁迫下生化组成、氨基酸和脂肪酸含量的变化。实验时间分别为饥饿0d(S0)、饥饿3d(S3)、饥饿6d(S6)、饥饿9d(S9)和饥饿12d(S12)。随着饥饿时间延长,水分显著升高(P<0.05),蛋白质、肝糖原和肌糖原显著降低(P<0.05),脂肪和灰分先显著降低(P<0.05),饥饿9d均出现回升(P<0.05)。氨基酸总量、必需氨基酸和非必需氨基酸含量均呈规则波动,饥饿12d均出现反弹现象,略高于实验起始值。饱和脂肪酸(SFA)呈先下降、后上升、再下降的趋势,单不饱和脂肪酸(MUFA)先上升后呈规则波动,多不饱和脂肪酸(PUFA)变化规律与饱和脂肪酸恰好相反,饥饿12d时仅高不饱和脂肪酸被保留,略高于实验起始值。双键位置不同的脂肪酸在饥饿过程中的损失速度也有差异,具体为∑n-9PUFA>∑n-3PUFA>∑n-6PUFA。     

短期饥饿对大鳍鱯生化组成、氨基酸和脂肪酸组成的影响

在水温(21±1)℃条件下,研究了大鳍鱯(Mystus macropterus)在短期饥饿胁迫下生化组成、氨基酸和脂肪酸含量的变化.实验时间分别为饥饿0 d(S0)、饥饿3 d(S3)、饥饿6 d(S6)、饥饿9 d(S9)和饥饿12 d(S12).随着饥饿时间延长,水分显著升高(P<0.05),蛋白质、肝糖原和肌糖原显著降低(P<0.05),脂肪和灰分先显著降低(P<0.05),饥饿9 d均出现回升(P<0.05).氨基酸总量、必需氨基酸和非必需氨基酸含量均呈规则波动,饥饿12 d均出现反弹现象,略高于实验起始值.饱和脂肪酸(SFA)呈先下降、后上升、再下降的趋势,单不饱和脂肪酸(MUFA)先上升后呈规则波动,多不饱和脂肪酸(PUFA)变化规律与饱和脂肪酸恰好相反,饥饿12 d时仅高不饱和脂肪酸被保留,略高于实验起始值.双键位置不同的脂肪酸在饥饿过程中的损失速度也有差异,具体为∑n-9PUFA＞∑n-3PUFA＞∑n-6PUFA.     

缺刻缘绿藻的光合膜脂与中性脂及其脂肪酸组成在氮饥饿/氮恢复培养过程中的变化

对缺刻缘绿藻(Myrmecia incisa)进行氮饥饿(4 d)/氮恢复(4 d和8 d)培养,研究其细胞中三酰甘油(TAG)和光合膜脂,主要是单半乳糖二酰甘油(MGDG)和二半乳糖二酰甘油(DGDG)的含量和脂肪酸组成的变化。结果表明TAG含量在氮饥饿胁迫下显著上升,而在氮恢复培养下逐渐下降;DGDG含量的变化趋势与TAG相反;MGDG的含量则始终呈现上升趋势。对脂肪酸组成进行分析发现花生四烯酸(ArA)主要存在于TAG中,且TAG中ArA的含量在氮饥饿胁迫下显著上升,并在氮恢复培养下逐渐下降。DGDG中ArA含量在氮饥饿/氮恢复过程中的变化与TAG中的相反;MGDG中ArA的含量在不同培养条件下始终增加。该结果表明在氮饥饿胁迫下DGDG可能向TAG合成提供ArA,而TAG在氮恢复后可向光合膜脂提供脂肪酸以供其合成。     

6种微藻生长及脂肪累积对氮含量变化的响应

研究了绿色巴夫藻、米氏凯伦藻、球等鞭金藻、三角褐指藻、海水小球藻、衣藻的生长及脂肪累积对氮含量变化的响应。试验结果表明,6种微藻生长及总脂对不同氮含量均有一定程度的响应。微藻生长,绿色巴夫藻、米氏凯伦藻、球等鞭金藻3种微藻响应明显,绿色巴夫藻以氮含量100%组生长最快,第10d时,比氮含量40%组快512%,比氮含量20%组及60%组分别快62%、61%;米氏凯伦藻氮含量80%组生长最快,第10d达到最高值,超出其他试验组约60%;球等鞭金藻氮含量80%组最快,第10d生长量超过100%试验组67%;三角褐指藻、海水小球藻、衣藻响应程度小于其他微藻。总脂积累,三角褐指藻氮含量80%组总脂含量最高,达细胞干质量的80.77%,是氮含量100%组2.5倍;绿色巴夫藻氮含量60%组最高,达细胞干质量的73.68%,是氮含量100%组3.4倍;其他4种微藻在降低氮含量后,总脂均超过细胞干质量的30%。三角褐指藻在生物柴油制备方向极具开发前景。     

饥饿对克氏原螯虾仔虾消化酶和生化成分的影响

对照组连续饱食投喂6 d,处理组分别饥饿1、2、3、4、5、6 d,每组3个重复,研究了短期饥饿对克氏原螯虾仔虾消化酶活力和主要生化成分的影响.试验结果表明,在饥饿过程中,处理组胃蛋白酶、类胰蛋白酶、淀粉酶及纤维素酶变化趋势相同,先减小后增大,饥饿2 d后,4种消化酶均最小;淀粉酶与类胰蛋白酶活力比值(A/T值)不断增大.随着饥饿时间的延长,克氏原螯虾仔虾体内水分含量逐渐增多,总蛋白含量和碳水化合物含量不断减少,总脂含量变化不显著(P>0.05).     

不同氮源对筒柱藻生长和生化组成的影响

以筒柱藻(Cylindrotheca fusiformis)为材料,分别以硝酸钠、氯化铵、尿素作为氮源的条件下对筒柱藻的生长状况、蛋白质、总糖、叶绿素含量进行了研究,结果表明:硝酸钠对筒柱藻的生长最好,密度达3.5×109 L-1(cells/L),含氮组中的筒柱藻密度显著高于无氮组;尿素、氯化铵、硝酸钠对筒柱藻中蛋白质的影响没有显著差异,均在0.015mg/mL左右,硝酸钠组最高达0.017mg/mL,显著高于无氮组(0.011mg/mL);无氮组总糖含量最高达0.071 9mg/mL,其他三组略低于无氮组;各含氮组对筒柱藻中叶绿素的影响没有显著差异,均在10～12μg/mL左右,与无氮组(6.827 1μg/mL)差异显著。因此得出硝酸钠对筒柱藻的生长效果最好,可以在生产中使用硝酸钠作为氮源。     

营养条件对四种海洋微藻生化组分的影响

以2种甲藻和2种硅藻为研究对象,采用半连续培养方法,设置氮限制、磷限制、无营养限制3种营养条件,研究营养条件对4种海洋微藻总蛋白质、总碳水化合物和总脂的影响.试验结果表明,微藻在无营养限制时的单位藻细胞总蛋白质含量均显著高于氮限制,但与磷限制差异不显著,东海原甲藻、锥状斯氏藻、中肋骨条藻和牟氏角毛藻在无营养限制条件下分别比氮限制高出了19.6％、9.6％、48.6％和65.9％;在营养限制下的单位藻细胞总碳水化合物含量高于无营养限制,其中锥状斯氏藻和中肋骨条藻在磷限制下的单位藻细胞总碳水化合物含量分别为0.045、0.006 ng/个,是无营养限制的4倍多;在营养限制下,东海原甲藻、锥状斯氏藻、中肋骨条藻和牟氏角毛藻单位藻细胞总脂含量均高于无营养限制,其中磷限制时分别比无营养限制时高出0.6、3.0、0.8、0.7 ng/个,磷限制比氮限制对总脂含量的影响更为明显.     

不同饥饿时间对白斑狗鱼恢复投喂期间生长性能的影响

在水温22~26℃条件下,研究了在不同饥饿时间处理后再投喂对白斑狗鱼(Esox lucius)生长性能的影响,试验设置饥饿14、21、28、35、42 d组和正常投喂对照组,各组饥饿结束后恢复正常投饵,在投喂后以7 d为一个生长阶段,比较各处理组的增重率、特定生长率、摄食率、饲料系数,试验周期为56 d。结果显示,随着饥饿时间的延长,白斑狗鱼的总体重损失率呈逐渐升高的趋势,而各饥饿阶段体重损失率呈下降的趋势;各饥饿处理组恢复投喂后的增重率和特定生长率均显著高于对照组(P<0.05),且随饥饿时间的延长而逐渐升高,但在恢复投喂后的第35天,S14组(饥饿14 d组)与对照组无显著性差异(P>0.05);各饥饿处理组恢复投喂后的摄食率随饥饿时间的延长而显著性升高(P<0.05);饵料系数随饥饿时间的延长而逐渐下降,其中在第14天时,S42组(饥饿42 d组)的饵料系数显著高于其他饥饿处理组(P<0.05),与对照组无显著性差异(P>0.05)。在同一饥饿处理组,随着投喂时间的延长,增重率、特定生长率和摄食率均呈显著性下降的趋势(P<0.05),饵料系数呈升高的趋势,其中S14组在第35天时恢复到对照组水平。结果表明:摄食率升高和饵料系数下降是饥饿再投喂白斑狗鱼增重率显著上升的原因,且这种生长倾向随着恢复投喂时间的延长而不断减弱。     

磷对生长期草鱼肌肉理化参数、游离氨基酸、呈味核苷酸和游离脂肪酸组成的影响

[目的]本实验探索了磷对生长期草鱼肌肉常规营养组成和理化特性,肌肉中游离氨基酸、呈味核苷酸和游离脂肪酸组成的影响。[方法]实验选择初始体重为（256.22 ± 0.60 g）的健康草鱼540尾,随机分为6组,每组3个重复,分别饲喂含有效磷0.95（基础饲料组,未添加）、2.46、3.96、5.68、7.10和8.75 g/kg的饲料60天。[结果]结果显示,饲料中适宜水平的磷显著提高了生长期草鱼肌肉蛋白质、水分、羟脯氨酸、∑氨基酸、∑鲜味氨基酸（UAAs）、∑甜味氨基酸（SAAs）、肌苷酸（IMP）、∑不饱和脂肪酸、∑多不饱和脂肪酸（PUFA）含量以及pH0和pH12,而肌肉剪切力、组织蛋白酶B和L活力、乳酸、饱和脂肪酸（SFA）含量显著降低（P < 0.05）。适宜水平的磷还显著提高了PUFA/UFA及n-3 PUFAs/n-6 PUFAs比值,IMP和∑呈味氨基酸（UAAs+SAAs） 的滋味活性值（TAV）均大于1。[结论]结果表明,适宜水平有效磷提高了生长期草鱼（254.56-898.23 g）肌肉蛋白质含量、肌肉嫩度、系水力和pH值,增加肌肉风味氨基酸、核苷酸和脂肪酸含量,进而提高鱼类肌肉品质。     

黄颡鱼早期发育阶段受精卵和鱼体脂肪酸组成变化

研究了黄颡鱼受精卵孵化期间和仔鱼发育阶段脂肪含量和脂肪酸的组成变化规律.采用常规化学分析方法和气相色谱法对黄颡鱼从鱼卵受精开始至仔鱼孵化后未投饵的7 d内的脂肪含量和脂肪酸组成进行测定.结果表明,受精卵在整个孵化期间脂肪含量有下降趋势.受精卵中不饱和脂肪酸含量大于饱和脂肪酸含量.受精卵在整个孵化期间各种脂肪酸含量无明显变化.仔鱼孵化后,鱼体总脂肪含量急剧下降,总脂含量从0日龄的4.57%降低到7日龄的0.75%.仔鱼在饥饿期间鱼体脂肪酸组成发生明显变化,单不饱和脂肪酸含量下降最为明显,尤其是C18:1.仔鱼在饥饿期间,脂肪酸按n-9>n-6>n-3顺序被先后利用,黄颡鱼仔鱼发育阶段主要以单不饱和脂肪酸作为能量代谢基质,而C20:4n6(AA)和C22:6n3(DHA)优先于C20:5n3(EPA)被保存下来.     

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。     

Effects of salinity on the fatty acid compositions of total lipid and individual glycerophospholipid classes of Atlantic salmon (Salmo salar) and turbot (Scophthalmus maximus) cells in culture

Cells from a relatively stenohaline marine species, turbot (Scophthalmus maximus) (TF) and an anadromous species, Atlantic salmon (AS) were cultured in media supplemented with NaCl to produce OPs varying from 300 to 500 mOsm kg^–1 and the direct effects of OP (salinity) on the fatty acid compositions of the main glycerophospholipid classes were determined. The most dramatic effects of salinity on total lipid fatty acids were observed in polyunsaturated fatty acids (PUFA) in TF cells. There was a graded decrease in the percentage of 18:2n-9, and consequently total n-9 PUFA, and concomitantly increased percentages of both total n-3 and n-6 PUFA with increasing salinity. The increased n-3 and n-6 PUFA was due to significantly increased percentages of the major fatty acids in each of these groups, namely 22:6n-3 and 20:4n-6, respectively. The reciprocal changes in n-9 PUFA and n-3/n-6 PUFA in TF cell total lipid resulted in the percentage of total PUFA not being significantly affected by changes in salinity. The graded decrease in 18:2n-9 with increasing salinity in TF cells was observed in all the major glycerophospholipids but especially PE, PI and PS. Increasing salinity resulted in graded increases in the percentages of 22:6n-3 in PE and PS in TF cells. The quantitatively greatest increase in the percentage of n-6 PUFA in TF cells occurred with 20:4n-6 in PC, PE and PL. There were less significant changes in the fatty acid compositions of glycerophospholipids in AS cells. However, the proportion of total n-3 + n-6 PUFA in PE varied reciprocally with the proportion of dimethylacetals in response to salinity. Similar reciprocal changes between fatty acids in response to salinity were also evident in the quantitatively more minor glycerophospholipids PS and Pl. In PS, the percentage of 22:6n-3 was significantly lower at 400 mOsm kg^–1 whereas the proportion of total monoenes was significantly higher at that salinity. A similar inverse relationship between total monoenes and 20:4n-6 (and, to a lesser extent total saturates) in response to salinity was noted in PI. The results show that environmental salinity, without whole-body physiological stimuli, has direct effects on the fatty acid composition of major glycerophospholipid classes in fish cells and that these effects differ in cells from different fish speciesAbbreviations ANOVA analysis of variance - BHT butylated hydroxytoluene - BSA bovine serum albumin - DMA dimethylacetals - EMEM Eagle's minimal essential medium - FCS fetal calf serum - GC gas chromatography - HBSS Hank's balanced salt solution (without Ca²⁺ and Mg²⁺) - OP osmotic pressure - PC phosphatidylcholine - PE phosphatidylethanolamine - PI phosphatidylinositol - PS phosphatidylserine - PUFA polyunsaturated fatty acid - TLC thin-layer chromatography     

南极磷虾粉脂质及脂肪酸组成分析

为分析南极磷虾粉的脂质成分,实验采用薄层层析法分离制备不同脂质组分,通过酸甲酯化衍生结合气相色谱/质谱法对不同脂质的脂肪酸组成进行比较研究.结果显示:①南极磷虾粉中脂质丰富,总脂含量高达11.37％,且以甘油三酯、磷脂和游离脂肪酸为主,胆固醇含量较低;②总脂脂肪酸主要为C16:0、C18:1n-9、C18:1n-7、C20:5n-3和C22:6n-3,且C20:5n-3和C22:6n-3占总脂肪酸含量的30.67％,表明南极磷虾粉在脂质方面具有较高的营养价值和开发潜力.③不同脂质的脂肪酸组成差异显著,胆固醇酯和甘油三酯中饱和脂肪酸和单不饱和脂肪酸含量均显著高于游离脂肪酸和磷脂(P＜0.05);而游离脂肪酸和磷脂富含多不饱和脂肪酸,两者含量分别为48.50％和49.96％,远高于胆固醇酯和甘油三酯的13.11％和24.36％,具有显著差异(P＜0.05).     

Essential fatty acid requirements of cultured marine fish larvae

Feeding of marine fish larvae is, in most cases, limited to the administration of two species of live prey. This reduction in the range of food available for the cultured larvae may occasionally lead to nutritional imbalances or deficiencies. A large amount of research has been recently devoted to the study of the essential fatty acid requirements of marine fish larvae. Studies on the biochemical composition of developing eggs and larvae, as well as the comparison of the patterns of loss and conservation during starvation, pointed out the importance of n-3 HUFA and arachidonic acid as essential fatty acids for larvae of marine fish. The biochemical composition of marine fish larvae, in terms of lipid content and fatty acid composition of total and polar lipids, is modified by dietary levels of essential fatty acids. Larval growth, survival and activity have also been reported to be affected by dietary levels of essential fatty acids. In addition, some pathological signs, such as hydrops or abnormal pigmentation, have been related to essential fatty acid deficiency in these fish. Based on these effects, the essential fatty acid requirements of marine larval fish have been reported to range between 0.3 and 55 g kg^?1 n-3 HUFA on a dry weight basis, suggesting that quantitative requirements of fish larvae may differ from those of juveniles or adults. But quantitative requirements for larvae of the same species reported by various authors are often contradictory. These differences are discussed in relation to the dietary lipid content, ratio 20:5n-3/22:6n-3 and culture conditions used.     

瓯江彩鲤生殖周期内卵巢成熟系数及脂类、脂肪酸的变化

采用生化方法测定了瓯江彩鲤(Cyprinus carpio var.color)卵巢不同发育时期的成熟系数及卵巢脂类、脂肪酸含量与组成,旨在了解瓯江彩鲤卵巢中脂类、脂肪酸的变化与卵巢发育及卵细胞成熟之间的关系。结果显示:卵巢中总脂含量在产卵前最高,占干重17.62%,产卵后显著下降到12.84%(P<0.05),到快速生长期又出现稍微下降,之后在越冬期开始呈上升趋势。4个时期中,C16∶0(软脂酸)、C18∶1n-9c(油酸)、C18∶2n-6c(亚油酸)均是卵巢中的主导脂肪酸,其含量显著高于其它脂肪酸(P<0.05);产卵前,卵巢中脂肪酸含量高,但种类较少,产卵后,卵巢中脂肪酸含量低,但种类较多;随卵巢的发育,不饱和脂肪酸的比例增加,从快速生长期到产卵前,C20∶4n-6(ARA)与C22∶6n-3(DHA)的含量逐渐上升,最高分别达11.63 mg/g、17.80 mg/g。结果表明:不同时期卵巢中脂类含量与成熟系数呈正相关,卵巢成熟需积累较多脂类物质。不饱和脂肪酸尤其是DHA、ARA对卵巢的成熟具有重要作用。     

The effect of culture on morphology, lipid and fatty acid composition, and polyunsaturated fatty acid metabolism of rainbow trout (Oncorhynchus mykiss) skin cells

Rainbow trout (Oncorhynchus mykiss) skin cell cultures were obtained by trypsinization of the tissue and grown in Leibovitz L-15 medium. Lipid class compositions, and fatty acid profiles of total lipids and individual phospholipid classes were determined at different times of culture. The metabolism of polyunsaturated fatty acids (PUFA) was investigated by incubating primary cultures after 7 and 14 days with [1-¹⁴C]18:2n-6 and [1-¹⁴C-]18:3n-3. The change in morphology between epithelial-like primary cultures and fibroblastic-like secondary subcultures was accompanied by alterations in the lipid composition. Polar lipids became predominant by 14 days in culture. The relative proportions of phosphatidylcholine (PC), the most abundant phospholipid, phosphatidylinositol and cholesterol increased significantly, while sphingomyelin decreased. Saturated fatty acids, 18:1n-9, n-6 and n-9PUFA were more abundant in total lipid in cultures at 14 days and 4 months than in cells initially isolated which contained higher percentages of longer chain monoenes and n-3PUFA. The changes in fatty acid composition with time in culture were observed in all the major phospholipid classes. Rainbow trout skin cells in culture desaturated and elongated both 18:2n-6 and 18:3n-3, with 20:4n-6 and 20:5n-3 being the most abundant products, respectively. PC presented the highest incorporation of radioactivity, especially following incubation with 18:3n-3. Lipid metabolism in general increased with the age of primary cultures, with both the amount of C18 PUFA incorporated and metabolized by desaturation/elongation significantly increased in 14 day cultures compared to 7 day cultures. Product/precursor ratios calculated for both n-6 and n-3 fatty acids showed that, while 6 desaturase activity was increased significantly with cell age, 5 desaturase activity was more affected by the fatty acid series, with 18:3n-3 being more readily transformed to 20:5n-3 than 18:2n-6 to 20:4n-6. Further desaturation of 20:5n-3 to hexaenes was low. Overall, the data suggested that the trout skin cell cultures were more similar to mammalian skin fibroblasts than mammalian epidermal/keratinocyte cultures.     

Dynamics of Total Body Fatty Acids During Early Ontogeny of Pikeperch (<Emphasis Type="Italic">Sander lucioperca</Emphasis>) Larvae

The fatty acid composition of pikeperch (Sander lucioperca) was determined according to their physiological status, during starvation (10 days) and feeding (28 days). In starved larvae, polyunsaturated, monounsaturated and saturated fatty acids were utilized as metabolic substrates until day 9. At day 10, all fatty acid levels remained stable or, at least, increased in larval body. Among fatty acids, docosahexaenoic acid 22:6 n-3 was used preferentially (20.3% from total fatty acids utilized) followed by palmitoleic acid 16:1 n-7 (13.9%) and then by oleic 18:1 n-9 (12.3%), linoleic 18:2 n-6 (10.1%), linolenic 18:3 n-3 (9.7%) and eicosapentaenoic 20:5 n-3 (9.1%) acids. On the other hand, arachidonic acid 20:4 n-6 was utilized very lowly (0.3%). In fed larvae, no utilization of body fatty acids was observed during the experiment. It seems that energy requirements (and others) of fed larvae were satisfied by feed.     

Fatty Acids Profile,Atherogenic, Thrombogenic,and Polyene Lipid Indices in Golden Grey Mullet (Liza aurata) and Gold Band Goatfish (Upeneus moluccensis) from Mediterranean Sea

ABSTRACT

The aim of this work was to study the seasonal variations of the proximate compositions, fatty acids contents, and related lipid indices (atherogenic index [AI], thrombogenic index [TI], and polyene index [PI]) of golden grey mullet (Liza aurata) and gold band goatfish (Upeneus moluccensis) caught from the northeastern Mediterranean Sea. Proximate compositions and fatty acid contents of both fish species showed statistically significant seasonal variations (p < 0.05). The lipid contents were highest in autumn and lowest in winter in golden grey mullet and gold band goatfish. The main saturated and unsaturated fatty acids were palmitic acid (C16:0), stearic acid (C18:0), palmiteoleic acid (C16:1n-7), oleic acid (18:1n-9c), arachidonic acid (C20:4n-6), eicosapentaenoic acid (EPA, C20:5n-3), and docosahexaenoic acid (DHA, C22:6n-3). The total polyunsaturated fatty acids in gold band goatfish did not show any differences among the seasons, whereas that in golden grey mullet was highest in winter. Levels of EPA, DHA, and n-3/n-6 ratios, as well as AI, TI, and PI, were significantly changed among seasons. The results show that golden grey mullet and gold band goatfish, which are among the important fish in Turkey and of commercial value, are a good source for human consumption in terms of their nutritional quality.