Seasonal variation in the body composition, amino acid, fatty acid and glycogen contents of triploid Pacific oyster, Crassostrea gigas in western coastal waters of Korea

We examined the seasonal variation of the proximate, amino acid, fatty acid composition and glycogen contents of triploid Pacific oyster cultured in western coastal waters of Korea in 2015. The specimens were collected in February, May, August and November from off-bottom farming site. The lipid content was the highest in winter season (February, $2.10{\pm}0.06%$), the protein content was the highest in autumn season (November, $9.09{\pm}0.04%$) while the moisture and ash content was the highest in summer season (August, $86.00{\pm}0.12%$ and $2.67{\pm}0.03%$, respectively). The total amino acid contents was the highest in winter season (1,011.5 mg / 100 g), decreased gradually and was the lowest in summer season (486.7 mg / 100 g). The total amino acid composition was dominated by taurine, aspartic acid, glutamic acid, glycine and alanine. In the fatty acid composition, the two fatty acids, eicosapentaenoic acid and docosahexaenoic acid, which comprised that as much as 50% of the total fatty acid contents, were dominated during all season. The glycogen content was the highest in summer season ($1.26{\pm}0.03g$ / 100 g) although it was stable during the other season with the range of $0.69{\pm}0.04-0.86{\pm}0.01g$ / 100 g. Taken together, these results suggest that triploid pacific oysters have high commercial value not only in winter season but in summer season because they do not spawn and have high contents of glycogen comparing with those of diploid oyster in this period.

서해안 3배체 굴 (Crassostrea gigas) 의 계절별 체성분, 아미노산, 지방산 및 글리코겐 함량 변화

본 연구는 2015년 우리나라 서해안에서 양식된 3배체 굴의 일반성분, 지방산, 아미노산 조성 및 글리코겐 함량의 계절적 변화를 조사하였다. 지방 함량은 겨울철에 가장 높았으며 (2월, $2.10{\pm}0.06%$), 단백질 함량은 가을철에 (11월, $9.09{\pm}0.04%$) 에서 가장 높았고 수분과 회분은 여름철 (8월, $86.00{\pm}0.12%$ 및 $2.67{\pm}0.03%$) 에 가장 높았다. 총아미노산 함량은 겨울철 (1,011.5 mg/100 g) 에 가장 높았고, 점차적으로 감소하여 여름철에 가장 낮았다 (486.7 mg/100 g). 아미노산조성은 taurine, aspartic acid, glutamic acid, glycine 및 alanine 등이 주요 아미노산으로 분석되었다. 지방산 조성에서 전체 지방산 함량의 50 % 이상을 차지하는 지방산은 EPA와 DHA로 확인되었다. 글리코겐 함유량은 여름철에 가장 높았으며 ($1.26{\pm}0.03g/100g$), 다른 시기에는 $0.69{\pm}0.04-0.86{\pm}0.01g/100g$의 범위로 일정한 함량을 보였다. 이상의 결과를 종합해 볼 때, 3배체 굴은 불임처리를 통해 산란을 하지 않아 여름철에 글리코겐 함량이 높아 겨울철뿐만 아니라 여름철에도 상업적 가치가 높은 것으로 확인되었다.