Histochemical and immunohistochemical analysis of testicular morphology and spermatogenesis in Gymnotus carapo (Teleostei: Gymnotidae).

This work aims to study the testicular morphology and spermatogenesis of Gymnotus carapo to provide information on their reproductive biology which is useful in managing this species as a fishing resource. The testicles were isolated and fixed in 10% formalin; subsequently, they were processed for scanning electron microscopy with conventional histological technique. To analyze the cell proliferation of germline cells and Sertoli cells, immunodetection of the proliferating cell nuclear antigen (PCNA) protein was performed.