Effect of various medium compositions on survival and hatching rates of embryos of the giant freshwater prawn Macrobrachium rosenbergii cultured in vitro

抄録

The effectiveness of in vitro embryo culture of the giant freshwater prawn Macrobrachium rosenbergii depended on the age of the embryos at the onset of culture and on the concentrations of various compositions in the medium. Embryos that started being cultured on day 0.5 after oviposition were more sensitive to variations in the medium compositions than those that started being cultured on day 10.5 after oviposition. An optimal NaCl level was essential for embryonic development, survival, hatching and survival of the newly hatched larvae. Variations of NaCl or KCl levels dramatically altered embryonic development, and variation of the MgCl₂+MgSO₄ level significantly lowered survival of the embryos that started being cultured at the early stage of development. In contrast, no significant change in embryonic development was observed upon variation of the CaCl₂ level. Hatching of the embryos required the presence of NaCl and CaCl₂ but not KCl or MgCl₂+MgSO₄. The ionic requirements of the newly hatched larvae differed from that of the developing embryos. Variations of NaCl, KCl or CaCl₂ but not MgCl₂+MgSO₄ levels significantly influenced the survival of the newly hatched larvae.