Hemolymph osmolality, ion concentrations and calcium in the structural organization of the cuticle of the giant freshwater prawn Macrobrachium rosenbergii

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• 作者：Marcy N. Wilder ; Do Thi Thanh Huong ; Safiah Jasmani ; Vidya Jayasankar ; Toyoji Kaneko ; Katsumi Aida ; Tamao Hatta ; Seiko Nemoto ; Andrew Wigginton
• 关键词：Calcium levels ; Cuticle structure ; Freshwater prawns ; Macrobrachium rosenbergii ; Molt cycle ; Osmoregulation
• 刊名：Aquaculture
• 出版年：2009
• 出版时间：1 July 2009
• 年：2009
• 卷：292
• 期：1-2
• 页码：104-110
• 全文大小：409 K

文摘

In the giant freshwater prawn, Macrobrachium rosenbergii, hemolymph osmolality was low at post-molt stages A and B, and increased gradually until intermolt stage C₀, reaching a maximum at stage D₂. Levels were lowest at the ecdysis (E) stage. Na⁺ and Cl^- hemolymph concentrations showed a pattern similar to that of osmotic concentrations during the molt cycle. On the other hand, Ca²⁺ hemolymph concentrations decreased significantly between stages A and C₀, and then increased significantly by nearly 60 % up until stage E. Total calcium levels in the hepatopancreas were highest at stage C₀. In parallel with hemolymph ionic changes, the distribution of calcium in the cuticle was analyzed using scanning electron microscopy–electron dispersion spectrometry (SEM–EDS). At the post-molt stage, calcium content was low, and the cuticle consisted of one layer. At stage C₀, the cuticle was highly calcified, and calcium occurred until a distance of 135 μm from the surface at stage C₀. In addition, the cuticle consisted of the present layer and a newly-forming layer. Calcium content was lower at stage D₂, but calcium still existed in the exocuticle. At stage E (discarded cuticle), the cuticle consisted of the exocuticle layer only.