Morphologic analysis of atretic follicles in the Chinese soft-shelled turtle, Pelodiscus sinensis

The Chinese soft-shelled turtle (Pelodiscus sinensis) and its eggs have been utilized as both a source of nutrition and medicine for thousands of years. In the present study, follicular atresia was investigated by morphological analysis as an important factor affecting clutch size. Results showed that follicular atresia can be divided into four stages: (1) development of follicular cell disorder; (2) massive cellular proliferation in the ooplasm with elimination of yolk granules; (3) large amounts of erythrocytes appearing in the ooplasm; (4) gradual degeneration of atretic follicles. For the first time, we have shown follicular atresia to be a dynamic process in P. sinensis and found that yolk granules are eliminated by both liquefaction as well as non-liquefaction processes. The present study may provide detailed morphologic analysis for further research into egg quality and clutch size in P. sinensis.