Differential expression of neuropeptide F during embryogenesis, and its promoting effect on embryonic development of the freshwater prawn, Macrobrachium rosenbergii

In the present study, we examined differential expression of Macrobrachium rosenbergii neuropeptide F (MrNPF) transcripts, and studied the presence of MrNPF during embryonic stages. We further investigated the effect for MrNPF on embryonic development of M. rosenbergii. By using RT-qPCR, the MrNPF mRNA levels showed a gradual increase from the early embryonic stages to the late embryonic stages. This coincides with initial expression of MrNPF immunoreactivity (MrNPF-ir) in the early embryonic stages and later strong MrNPF-ir in the late embryonic stages. Treating with MrNPF at doses of 10(-6) and 10(-7) mol/prawn into the female prawns significantly shortened the lengths of embryonic periods, exhibited faster attainment of each embryonic stage, and increased the number of proliferative cells, compared with the control groups (P < 0.05). In addition, the percent of fertilization was higher in the MrNPF-treated group at a dose of 10(-6) mol/prawn, compared with the control groups (P < 0.05). The mean egg size of MrNPF-treated groups at doses of 10(-6) and 10(-7) mol/prawn also was slightly larger than that of the control groups. Following treatment with three doses of MrNPF, developing embryos also showed normal development in terms of eye pigmentation and differentiation, appearance of a beating heart, appearance of oily yolk, formation of the abdomen, and folding of the telson. Taken together, our results provide new insight into the potential role of MrNPF in the embryonic development of M. rosenbergii; this knowledge may be useful in improving methods of seed production in this economically-important crustacean species.