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

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 stage Ⅲ to stage Ⅴ) 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, respectively, 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 stage Ⅲ to stage Ⅴ, 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 stage Ⅳ and stage Ⅴ were all less than 0.46, which means that female C. nasus in the Yangtze River had a good egg quality.