Spermatophore replacement of pink shrimp Farfantepenaeus brasiliensis after manual extrusion: Effect of molting

• Pink shrimp spermatophore replacement was evaluated after manual extrusion.
• Three replacement stages were identified: unformed, partially formed and formed.
• Partially formed have the same weight and lower sperm count than those formed.
• After manual extrusion, spermatophores are gradually formed in until 16 days.
• When molting occurs, spermatophores are replaced in approximately 24 h.

This study aimed to evaluate Farfantepenaeus brasiliensis spermatophore replacement after manual extrusion and analyze the effect molting has on this process. Three trials were conducted. In the first trial, the replacement of spermatophores after extrusion was macroscopically evaluated via an analysis of morphological changes in the terminal ampoule during the formation of new spermatophores. In the second trial, the sperm quality in the different stages of spermatophore replacement identified in the first trial was compared. In the third trial, the replacement time of spermatophores after extrusion was determined, with and without molting. In all trials, 30 manually extruded wild males were individually stocked in 0.49 m2 tanks using different samples of randomly selected animals for each trial. The results were obtained by daily visual examination of the gonopore and coxae regions of the fifth pereiopod pair and sperm quality analyses. In trial 1, three successive macroscopic stages of spermatophores were observed during replacement: unformed, partially formed and formed. In trial 2, the sperm count in formed spermatophores was significantly higher than that in partially formed spermatophores, whereas the spermatophore weight was not significantly different. Therefore, spermatophore replacement most likely comprises the following phases: (1) deposition of a primitive spermatophore with all structural components in each terminal ampoule; (2) gradual deposition of spermatozoa; and (3) stiffening of the spermatophore into typical elongate form. Trial 3 demonstrated that after extrusion, spermatophores are completely formed in 16 days without molting and in 24 h with molting. Spermatophores formed after molting have sperm quality similar to that of gradually formed spermatophores.