Effect of Different Regional Characteristics of Spawning and Growing Sites on Growth and Taste of Pacific Oyster, Crassostrea gigas

While Pacific oysters are important commercial aquaculture species worldwide, the effect of hormonal regulation and environmental conditions on growth and taste profile have not been fully known. Insulin-like growth factor (IGF) systems are known to play a major role in regulating neuroendocrine functions across various physiological processes and are particularly involved in growth. IGFs expression also is directly related to the nutritional status of vertebrates, however, full mechanism has not been clearly identified in bivalves. In this study, differences in growth, IGFs expression, and taste according to cultivation site of Pacific oysters were investigated. Oysters were collected in three different spawning sites located on the south coast of Korea in July 2022 and hardened until June 2023. Then, the oysters were cultured in two different growing sites (Tongyeong site, TS; Geoje site, GS) for six months. The total weight of oysters, along with their condition index and tissue weight rate, was significantly higher in TS. Additionally, IGF expression was higher in TS during most of the sampled months. However, oysters from the GS scored higher in taste evaluations. The IGFs system in oysters shows a similar trend to previous studies, with higher levels in faster-growing individuals, suggesting oysters in TS were more adequately nourished by the surrounding environment in this research. However, in taste evaluation, oysters from the GS showed better results than those from the TS. Despite these results, determining whether one site is superior in certain aspects is still not fully possible, which warrants further investigations.