长江下游雌性刀鲚生殖洄游过程中脂肪酸含量及其组分的变化

Changes of fatty acid content and its components in different tissues during spawning migration processes of female Coilia nasus in the lower reaches of the Yangtze River

为阐明长江刀鲚体内脂肪酸在生殖洄游过程中的转化规律,本研究采用三氟化硼甲酯化法对采自长江下游不同发育时期(Ⅲ～Ⅴ期)的雌性刀鲚洄游群体的脂肪酸进行测定,对各类脂肪酸在卵巢、肌肉和肝胰腺的组成及其含量变化作了分析。结果显示,雌性刀鲚从Ⅲ期发育至Ⅴ期,卵巢总脂肪酸含量上升了148.89 mg/g,而肌肉和肝胰腺总脂肪酸含量则分别下降了109.57和160.58 mg/g。不同发育时期,卵巢、肌肉和肝胰腺的脂肪酸组成基本相同,均含有3大类24种脂肪酸,其中饱和脂肪酸(SFA)9种、单不饱和脂肪酸(MUFA)6种和多不饱和脂肪酸(PUFA)9种。所有脂肪酸中,以油酸(C18:1n9c)的含量最高,占各组织脂肪酸总量的18%以上。分析发现,在Ⅲ期至Ⅴ期发育过程中,雌性刀鲚肌肉中的C18:1n9c下降了86.36%,卵巢中则增加了2.62倍;必需脂肪酸C18:2n6和C18:3n3在肌肉中分别下降了74.00%和82.26%,但在卵巢中分别增加了225.87%和183.96%;肌肉中DHA (C22:6n3,二十二碳六烯酸)含量减少了2.6倍,而卵巢中却增加了近3倍,表明这些脂肪酸与繁殖活动的关系很密切。研究还发现,Ⅳ期和Ⅴ期卵巢中ARA (C20:4n6,花生四烯酸)/EPA (C20:5n3,二十碳五烯酸)的比值均小于0.46,可能预示着长江刀鲚有较好的卵子质量。

In order to elucidate the transformation rule of fatty acids in body of female Coilia nasus during the spawning migration process,the fatty acid content and its components were determined in different tissues at different ovarian developmental stages(from stageⅢto stageⅤ)of female C.nasus collected from the lower reaches of the Yangtze River.The changes in the components and contents of various fatty acids in the ovary,muscle and hepatopancreas were analyzed.The results showed that the total fatty acids content in ovary increased by 148.89 mg/g,in muscle decreased by 109.57 mg/g and in hepatopancreas decreased by 160.58 mg/g,respe-ctively,during the period of ovarian development from stages III to V.The fatty acids components of ovary,muscle and hepatopancreas are basically the same at different ovarian developmental stages.They all contain three types and 24 kinds of fatty acids,including 9 saturated fatty acids(SFA),6 monounsaturated fatty acids(MUFA)and 9 polyunsaturated fatty acids(PUFA).Among all the fatty acids,the content of oleic acid(C18:1n9c)was the highest,accounting for more than 18%of the total amount of fatty acids in each tissue.During the ovarian development from stageⅢto stageⅤ,the content of oleic acid decreased by 86.36%in muscle,increased by 2.62 times in ovary;the content of essential fatty acids C18:2n6 and C18:3n3 decreased by 74.00%and 82.26%in muscle respectively,but increased by 225.87%and 183.96%respectively in ovary;the content of DHA decreased by 2.6 times in muscle,while increased by nearly 3 times in ovary.All of these showed that these fatty acids are closely related to reproductive activities.The present study also found that,the values of ARA/EPA in ovary of stageⅣand stageⅤwere all less than 0.46,which means that female C.nasus in the Yangtze River had a good egg quality.