Prostaglandin E_(2) involvement in the reproduction of small abalone,Haliotis diversicolor

Prostaglandin E2(PGE2)has been reported to be involved in reproduction as one of the most abundant and widely distributed prostaglandins in invertebrates.Regulating gonad development and gamete production in mollusks can greatly assist artificial breeding,which is believed to promote the commercial benefits of various mollusk species.In the present study,the contents of PGE2 in the gonads of abalone at different developmental stages(maturing stage,ripe stage,and spawning stage)and reproduction states(before and after spawning)were measured.A higher PGE2 level was found in the gonads of abalones at the ripe stage than other stages,and the highest PGE2 level was detected in the ovaries of female H.diversicolor in the UV-stimulated group.Then the effects of PGE2 injection on the spawning efficiency were explored,and the gamete emission rates of female and male abalone were significantly increased after PGE2 injection.Through qRT-PCR and in situ hybridization assay,higher expression levels and wide distribution of phospholipase A2(PLA2),cyclooxygenase 2(COX2),prostaglandin E synthases(PGES2),and prostaglandin E2 receptor 4(EP4)in the gonads of H.diversicolor were observed after spawning.It is speculated that PGE2 may promote the reproductive cycle in both male and female H.diversicolor,although the regulation mechanism of PGE2 in female and male abalone might be different.The results will be useful for the application of PGE2 in the abalone aquaculture practices to increase the reproduction efficiency in future.

Reproduction strategy of nocturnal marine molluscs:running for love

The cost of reproduction is the core driver of life history evolution in animals.This paper demonstrates that the cumulative distance moved and the duration of movement of sexually immature abalones,Haliotis discus hannai,kept in various male and female groups,were significantly higher than those of sexually mature individuals,except when kept in mixed cultures of mature males and females.After mixed-culture,sexually mature males moved significantly further and for a longer duration than mature female abalones,and even more so than mature male abalones of any other group.Examination of the LC-MS metabolomics of mature males cultured with sexually mature females(AM)and those cultured with sexually immature females(JM)showed that cyclic adenosine monophosphate(cAMP)acted as a differential metabolic biomarker.After 24-h uninterrupted sampling,the concentration of 5-HT and the expression levels of the 5-HT2 and 5-HT6 receptors in AM were significantly higher than those in JM.After further injection of 5-HT2 and 5-HT6 receptor antagonists,the concentrations of cAMP and PKA rose again,but the cumulative movement duration and distance of male abalones decreased significantly,showing that 5-HT was involved in the regulation of movement behavior of male abalones through the 5-HT2 and 5-HT6 receptor-activated cAMP-PKA pathways.The results demonstrated a significant increase in the movement endurance of mature male abalones cultured with mature females,providing a theoretical basis for understanding the adaptive life history strategies of abalones and suggesting ways to protect diverse benthic resources for abalones during the reproductive stage.