Flow Cytometric Analysis of Molt-Related Changes in Hemocyte Type in Male and Female Penaeus japonicus

Hemocyte cell suspensions obtained from male and female Penaeus japonicus were individually analyzed by flow cytometry through forward and side light-scatter parameters. The hemocyte cell suspensions were further characterized after cell sorting. This type of cell analysis has several advantages over microscopy techniques. After staining with phenoloxidase and peroxidase, the hemocytes were classified into the three classic categories of hyaline, semigranular, and granular cells. Significant cyclic differences were detected among the molting stages in both sexes. The hyaline cell population was predominant before and soon after the molt, decreasing over the intermolt. This decrease was, however, more prolonged in females. Thus, the hyaline cell population was dominant in stages B, D0, and D1 in males and only in stages B and D1 in females. Semigranular cells became predominant in females during the D0 stage.