Change in environmental salinity level is a major limiting factor for the aquaculture productivity because it imposes severe stress on organisms that in turn retards growth. The orange mud crab (Scylla olivacea) is an important coastal aquaculture species (farming is practised in 10‰–20‰ salinity levels) in Bangladesh. The present study was conducted to investigate the changes in growth, O₂ consumption and mRNA expression levels of five selected genes in the orange mud crab (S. olivacea) exposed to three different experimental salinity levels (0‰, 10‰ and 20‰) for three months. Crabs reared at 10‰ and 20‰, showed significantly higher (p < .05) growth performance and expression of growth regulatory genes (Actin and α‐amylase). The highest levels (p < .05) of O₂ consumption and expression of ion regulatory genes (Na⁺‐K⁺‐ATPase, V‐type H⁺‐ATPase and Diuretic Hormone) were obtained at 0‰. Moderate levels of growth and expression of selected candidate genes were observed at 10‰ treatment while the highest levels of growth and gene expression were obtained at 20‰ (control salinity). Strong interactions were observed between growth performance and expression of growth genes (R² = 0.81–0.91), and rate of O₂ consumption and expression of ion regulatory genes (R² = 0.83–0.93), implying that the selected genes are important candidates for growth and ionic balance in S. olivacea. Growth performance was found to be very low at 0‰ initially, after 30 days crabs showed better growth performance at this salinity level. It is thus inferred that orange mud crab individuals might require 3–5 days for acclimation to salinity stress but it can take at least 30 days for acclimation to regular growth. Results indicate that with proper acclimation, the orange mud crab (Scylla olivacea) can be farmed at low salinity conditions and possibly in freshwater condition.

中文翻译：

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盐度变化对橙泥蟹（Scylla olivacea）生长，耗氧量和所选候选基因表达模式的影响

环境盐度水平的变化是水产养殖生产率的主要限制因素，因为它给生物体带来了严重的压力，进而阻碍了其生长。在孟加拉国，橙泥蟹（Scyla olivacea）是重要的沿海水产养殖品种（在盐度水平为10‰–20‰的情况下进行养殖）。本研究旨在研究暴露于三种不同盐度（0‰，10‰和20‰）的橙泥蟹（S. olivacea）中五个选定基因的生长，O ₂消耗和mRNA表达水平的变化。三个月。以10‰和20‰饲养的螃蟹显示出更高的 生长性能（p <.05）和生长调节基因的表达（肌动蛋白和α-淀粉酶）。在0‰处获得最高水平 的O ₂消耗（p <.05）和离子调节基因（Na ⁺ -K ⁺ -ATPase，V型H ⁺ -ATPase和利尿激素）的表达。在10‰处理下观察到中等水平的生长和所选候选基因的表达，而在20‰（对照盐度）下获得最高的生长和基因表达。观察到生长性能和生长基因表达之间的强相互作用（R ²  = 0.81-0.91）和O ₂速率消耗和离子调节基因的表达（R ²  = 0.83-0.93），这表明所选的基因是S中生长和离子平衡的重要候选者。橄榄石。人们发现，在此盐度水平下30天后，螃蟹表现出更好的生长性能，最初的生长性能非常低，为0‰。因此可以推断出，橙泥蟹个体可能需要3-5天才能适应盐分胁迫，但至少需要30天才能适应正常生长。结果表明，通过适当的驯化，橙泥蟹（Scyla olivacea）可以在低盐度条件下并可能在淡水条件下养殖。