Histocytological changes in the corpuscles of stannius in relation to ovarian development of freshwater featherback Notopterus notopterus (Pallas) during growth, maturation and spawning phases

Abstract

The corpuscles of Stannius (CS) of important food fish Notopterus notopterus were studied in relation to ovarian maturation. Cytological status of CS were correlated with the ovarian development during growth, maturation and spawning phases. The cytoarchitecture of CS in N. notopterus showed two principle types of secretory cells (Type I and Type II) arranged along the connective tissue septa. Different germ line cells were recognized on the basis of size and histoarchitectural morphology of cells. The Type-II cells varied according to the proliferation of different stages of oocytes in harmony with the various reproductive phases. It was found that at the end of growth phase and onset of maturation phase the diameter along with cytoplasmic granules of Type-I cells increased considerably than the Type-II cells, which was correlated with the occurrence of cortical alveolus and yolk granule stages in the ovary. During the end of maturation and spawning phases the diameter of Type I cells further increased along with chromophobic cytoplasm and hypertrophied nuclei were arranged in clusters encircling the blood vessels. No significant changes were noticed in the Type II cells. These momentous changes correlated with the dynamic cytological activities like vitellogenesis and occurrence of mature oocytes in the ovary. Thus the cytological changes of the CS during growth, maturation and spawning phases accomplished with the ovarian maturation in N. notopterus.