Captivity, ablation and starvation of the prawn Penaeus monodon affects protein and lipid content in ovary and hepatopancreas tissues

To investigate the effect of captivity and ablation on ovary development in Penaeus monodon, two experiments were conducted using prawns captured from waters in North Queensland, Australia. The first experiment quantified total protein and lipid in the ovaries and hepatopancreas prior to and during ovary maturation. The second experiment examined the effect of ablation, captivity and short term starvation on previtellogenic ovary composition.Results revealed the captive conditions of this study caused a reduction in lipid content in previtellogenic ovaries. Further investigation of the effect of short term starvation on previtellogenic prawns showed that ablation reduced the depletion of protein and lipid from the ovary and the depletion of protein from the hepatopancreas. This suggests that eyestalk neuropeptides are involved in regulating nutrient levels in these tissues prior to vitellogenesis. In addition, ablation appears to increase the hepatopancreas contribution to lipids accumulating in the vitellogenic ovary although captive conditions (including diet) may also play a role in this increase. Despite these significant effects on immature ovaries, the current study showed that, at least for the first post-ablation maturation cycle, captivity and ablation caused no significant change in the levels of lipid or protein in mature ovaries. Thus, the effects of captivity on previtellogenic ovaries and the role of ablation in regulating nutrient uptake at this developmental stage warrants further study with a particular view to improving spawning frequency.