Histomorphological Study of Litopenaeus vannamei Ovary in Different Stages of the Reproductive Cycle

The purpose of the current study is the histomorphologic survey of Litopenaeus vannamei shrimps ovarian development is different stages of the reproductive cycle.30 female L. vannamei shrimps from ChoebdehsCultivation and Breeding Center in Abadan city were examined. Sampling was done in the spring (May 2013). The samples were transfered to the histology lab of Khorramshahr University of Marine Science and Technology. After tissue passage, tissue sections were made from them and were stained. The results of this investigation showed that the L. vannamei shrimps have asynchronous ovary, also four stages of ovarian development can be identified in this species of shrimp. In addition, stages of follicular development were divided into five stages including chromatin nucleolus, peri nucleolus, cortical alveolus, primary vitellogenesis and final vitellogenesis. Cortical alveolus stage was rarely observed. It seems that in ovary of Litopenaeus vannamei, peri nucleolus follicles quickly entered to first stage of vitellogenesis. It was also shown that ovaries can be divided into four phases morphologically.