Ovary maturation, oocyte differentiation, and embryonic development in shrimp are highly dependent on nutritional lipids taken up by female broodstocks. These lipids are important as energy sources as well as for cell signaling. In this study, we report on the compositions of major lipids, i.e. phosphatidylcholines (PCs), triacylglycerols (TAGs), and fatty acids (FAs), in the ovaries of the banana shrimp, Penaeus merguiensis , during ovarian maturation. Thin-layer chromatography analysis showed that the total PC and TAG signal intensities increased during ovarian maturation. Further, by using gas chromatography, we found that (1) FAs 14∶0, 16∶1, 18∶1, 18∶2, 20∶1, and 22∶6 proportionally increased as ovarian development progressed to more mature stages; (2) FAs 16∶0, 18∶0, 20∶4, and 20∶5 proportionally decreased; and (3) FAs 15∶0, 17∶0, and 20∶2 remained unchanged. By using imaging mass spectrometry, we found that PC 16∶0/16∶1 and TAG 18∶1/18∶2/22∶6 were detected in oocytes stages 1 and 2. PCs 16∶1/20∶4, 16∶0/22∶6, 18∶3/22∶6, 18∶1/22∶6, 20∶5/22∶6, and 22∶6/22∶6 and TAGs 16∶0/16∶1/18∶3, 16∶0/18∶1/18∶3, 16∶0/18∶1/18∶1, and 16∶0/18∶2/22∶6 were present in all stages of oocytes. In contrast, the PC- and TAG-associated FAs 20∶4, 20∶5, and 22∶6 showed high signal intensities in stage 3 and 4 oocytes. These FAs may act as nutrition sources as well as signaling molecules for developing embryos and the hatching process. Knowledge of lipid compositions and localization could be helpful for formulating the diet for female broodstocks to promote fecundity and larval production.

No abstract

Limitation of food availability (starvation) is known to influence the reproductive ability of animals. Autophagy is a lysosomal driven degradation process that protects the cell under metabolic stress conditions, such as during nutrient shortage. Whether, and how starvation-induced autophagy impacts on the maturation and function of reproductive organs in animals are still open questions. In this study, we have investigated the effects of starvation on histological and cellular changes that may be associated with autophagy in the ovary of the giant freshwater prawn, Macrobachium rosenbergii. To this end, the female prawns were daily fed (controls) or unfed (starvation condition) for up to 12 days, and the ovary tissue was analyzed at different time-points. Starvation triggered ovarian maturation, and concomitantly increased the expression of autophagy markers in vitellogenic oocytes. The immunoreactivities for autophagy markers, including Beclin1, LC3-II, and Lamp1, were enhanced in the late oocytes within the mature ovaries, especially at the vitellogenic stages. These markers co-localized with vitellin in the yolk granules within the oocytes, suggesting that autophagy induced by starvation could drive vitellin utilization, thus promoting ovarian maturation.

No abstract

The central nervous system (CNS) is often intimately involved in reproduction control and is therefore a target organ for transcriptomic investigations to identify reproduction-associated genes. In this study, 454 transcriptome sequencing was performed on pooled brain and ventral nerve cord of the female mud crab (Scylla olivacea) following serotonin injection (5 µg/g BW). A total of 197,468 sequence reads was obtained with an average length of 828 bp. Approximately 38.7% of 2,183 isotigs matched with significant similarity (E value < 1e−4) to sequences within the Genbank non-redundant (nr) database, with most significant matches being to crustacean and insect sequences. Approximately 32 putative neuropeptide genes were identified from nonmatching blast sequences. In addition, we identified full-length transcripts for crustacean reproductive-related genes, namely farnesoic acid o-methyltransferase (FAMeT), estrogen sulfotransferase (ESULT) and prostaglandin F synthase (PGFS). Following serotonin injection, which would normally initiate reproductive processes, we found up-regulation of FAMeT, ESULT and PGFS expression in the female CNS and ovary. Our data here provides an invaluable new resource for understanding the molecular role of the CNS on reproduction in S. olivacea.