Seasonal Variation in Lipids and Fatty Acid Composition of Neutral and Phospholipids of Hibernant Fishes(I) - Variation of Muscle Lipid Compositions of Loach (Misgurnus mizolepis) -

동면 어류의 지방질과 중성 및 인지질 조성의 시기적 변화(I) - 미꾸라지 근육 지질 조성의 변화-

The seasonal variation in lipids, and fatty acid composition of neutral lipid(NL) and phospholipid(PL) contained in the muscles of hibernant fish(loach) were investigated. In the investigation, four groups of wild loaches ere used, those caught May, 1993(before spawning period), August, 1993(after spawning period), November, 1993(just before hibernation) and March, 1994(just after hibernation). The NL was the most abundant in muscle lipid, followed by PL and glycolipid(GL), and also the composition and variation patterns were almost similar between female and male throughout all the periods. NL content began to increase gradually after March and came to the maximum in August(under 90%) ; hereafter got to decrease gradually again and came to the minimum in March of the next year(under 60%). While the variation-pattern of GL and PL was in inverse proportion with that of NL and their content came to the maximum in March of the next year. The NL and PL fractions were mainly consisted of triglyceride and phosphatidyl choline respectively, and both of the contents showed the highest value in August, the lowest in March of the next year. The major fatty acids in NL fraction were 16:0, 16:1, 18:1, 18:2 and 18:3($\omega$3). In particular, the ratio of 16:1 was much higher than that in PL, while those of highly unsaturated fatty acids(HUFAs) such as 20:4($\omega$6), 20:5($\omega$3) and 22:6($\omega$3) were much lower. The ratio of 16:0 in NL was almost constant through the year, however those of 16:1, 18:1, 18:2 and 18:3($\omega$3) showed a tendency to increase after March and were about 2~4% higher in May, compared with that in March, while those of HUFAs were about 2~4% lower. In particular, the ratio of 16:1 in NL continuously decreased after May and markedly decreased in March of the next year, but those of 18:1, 18:2 were almost constant until November. In August, saturates and monoenes were higher levels due to the slight increase of 18:0, 14:1 and 17:1 than in the other periods, while those of HUFAs decreased and the unsaturation(TUFA/TSFA) of NL showed the lowest value in August. On the contrary, saturates and monoenes gradually decreased after November and the most of them including 18:0, 16:1, 18:1 and 18:2 rapidly decreased in March of the next year, while 20:1, 20:4(~6), and 20:5(~3), and 22:6(~3) were in inverse proportion. PL consisted mainly of 16:0, 16:1, 18:1, 18:2, 20:4(~6), and 20:5(~3). Saturates and monoenes-composition showed almost no difference in March and May, while polyene acids ratio showed similar changes with that of NL. In August, the ratio of saturates(16:0, 18:0) were high but that of HUFAs were low, and after November 16:0, 18:0, 18:1, 18:2 and 18:3($\omega$3) began to decrease, while most of HUFAs increased in their composition-ratio until the marking increase of their unsaturation and the big changes of 18:2, 18:3($\omega$3), 20:4($\omega$6), 22:6($\omega$3) in March of the next year.

동면 어류인 미꾸라지를 일정시기(산란기전:5월, 산란기후:8월, 동면직전:11월, 동면직후:3월) 별로 채취한 다음 자.웅별 전육질부를 시료로 취하여 지방질과 중성 및 인지질 조성을 분석, 검토하였다. 중성지질이 구성지질의 대부분을 이루었고 다음은 인지질, 당지질순이었으며 그 조성과 변화 pattern이 자.웅이 거의 비슷한 경향을 나타내었다. 3월 이후 중성지질의 조성비가 점차 많아져 8월에는 90% 가까이 증가하였고 이후 점차 감소하여 이듬해 3월이 가장 많았다. 중성지질과 인지질 중에는 각각 triglyceride와 phosphatidyl choline 조성이 가장 많았으며 그 함량은 8월에 최고치를, 3월에 최소치를 나타내었다. 중성지질의 주요 지방산은 16:0, 16:1, 18:1, 18:2, 18:3($\omega$3) 등으로 이중 16:1 조성은 인지질보다 월등히 많았고 20:4($\omega$6), 20:3($\omega$3), 22:6($\omega$3) 등 고도 polyene산은 훨씬 적게 분포되었다. 중성지질의 지방산중 16:0 조성은 연중 거의 변화가 없었으나 16:1, 18:1, 18:2, 18:3($\omega$3)은 3월보다 5월이 2~4% 정도 높았고 고도 polyene산 조성은 그만큼 적었다. 이중 16:1 조성은 5월 이후 계속 줄어든 반면, 18:1, 18:2 w성은 11월까지 거의 비슷하였다. 또, 8월에는 18:0, 14:1, 17:1 조성의 증갈 포화 및 monoene산 조성이 다소 높아지고 고도 polyene산 조성은 더욱 줄어들어 불포화도가 최소치를 나타내었다. 11월부터는 그 반댈 포화 및 monoene산 조성이 점차 줄어들어 동면 직후인 3월에는 18:0, 16:1, 18:1 등 대부분의 포화산과 monoene산 및 18:2 조성이 더 큰 폭으로 떨어졌고 20:1, 20:4($\omega$6), 20:5($\omega$3), 22:6($\omega$3) 조성비는 그 만큼 더 높아지는 경향이었다. 인지질은 16:0, 16:1, 18:1, 18:2, 20:4($\omega$6), 20:5($\omega$3)이 주요 지방산이었고 3월과 5월 사이에 포화산과 monoene산 조성은 거의 차이가 없었으나 polyene산 조성은 중성지질과 비슷하게 변화였다. 8월에는 16:0, 18:0 등 주로 포화산 조성이 높아지고 고도 polyene산 조성은 그만큼 줄었으나 11월부터는 16:0, 18:0과 18:1, 18:2, 18:3($\omega$3) 조성이 다시 줄고 대부분의 고도 polyene산 조성은 점차 많아져 이듬해 3월에는 중성지질과 마찬가지로 불포화도가 더 큰 폭으로 커지고 특히 18:2, 18:3($\omega$3)과 20:4($\omega$6)와 22:6($\omega$3)의 변화가 두드러졌다.