The Effect of Neuroactive Compounds on Settlement of Pacific Oyster, Crassostrea gigas Pediveliger Larvae

We determined the effects of neuroactive compounds known as synthetic larval settlement inducers on the settlement of the Pacific oyster C. gigas pediveliger on the larval collector. Six types of the inducers, serotonin (5-HT), ${\gamma}$-amino butyric acid (GABA), L-3,4-dihydroxyphenylalanine (L-DOPA), norepinephrine, epinephrine and methyl bromide (MB) were tested. All the chemicals induced larval settlement, MB being the most effective with settlement rate of $42.7{\pm}2.7%$, followed by GABA ($35.4{\pm}2.0%$), 5-HT ($29.1{\pm}2.2%$), L-DOPA ($19.2{\pm}2.1%$), epinephrine ($15.2{\pm}0.9%$), and norepinephrine ($11.0{\pm}1.2%$). The chemicals ${\gamma}$-amino butyric acid and methyl bromide were also better in terms of settled density on the collector with their respective density of $1.97{\pm}1.42$ and $2.37{\pm}1.86\;ind/cm^2$, reminiscent of being most effective candidates for a larval settlement inducer in the oyster hatchery.

굴 Crassostrea gigas 부착기 유생의 부착에 미치는 신경전달물질종의 영향

굴 부착기 유생의 부착 유인 효과를 조사하기 위하여 6종류 (L-3,4-dihydroxyphenylalanine, serotonin, ${\gamma}$-amino butyric acid, norepinephrine, epinephrine, methyl bromide)의 신경전달물질을 채묘기질에 직접 처리하여 굴 부착기 유생의 부착 유인 효과를 조사하였다. 조사결과 평균 채묘율는 각각 $29.1{\pm}2.2%$, $35.4{\pm}2.0%$, $19.2{\pm}2.1%$, $11.0{\pm}1.2%$, $15.2{\pm}0.9%$ 및 $42.7{\pm}2.7%$ 로 MB 처리구에서 가장 높은 결과를 보였고, norepinephrine 처리구에서 유의적으로 가장 낮은 결과를 보였다 (P < 0.05). 채묘기질 $cm^2$당 부착밀도와 부착빈도는 ${\gamma}$-amino butyric acid와 methyl bromide 처리구에서 각각 $1.97{\pm}1.42$ 및 $2.37{\pm}1.86$ 마리/$cm^2$로 가장 높은 부착밀도를 보였다 (P < 0.05). 본 실험결과 굴 인공종묘배양장 등에서 부착기 유생의 부착요율을 높이는데, ${\gamma}$-amino butyric acid와 Methyl bromide를 이용하면 효과적일 것으로 보인다.