Qualitative and quantitative analysis of the ovarian maturation process of Penaeus vannamei after a production cycle

The present study analyzes the longitudinal and transversal organization of ovaries of Penaeus vannamei during maturation. For this purpose, oocyte diameter and proportion of area occupied by each oocyte class were quantified on the left and right sides and on five zones of the ovaries: anterior lobe, thoracic lobe, first abdominal segment, middle part of the abdominal lobe, and distal part of the abdominal lobe. Ovaries in vitellogenic (early and late) and cortical ovarian stages were considered for this analysis. The qualitative and quantitative analysis revealed that there were no differences in the left or right side and that only the zone of the first abdominal segment was clearly different from the other ones. When grouping data in cephalothoracic and abdominal regions, several differences were found, indicating a more advanced vitellogenic development in the cephalothoracic region. Thus, the homogeneous development of ovaries that is generally assumed in penaeid shrimps could have some limitations if a detailed analysis of oocyte development is needed.