Table 6 Histological characteristics of the gonadal development stages of P. textile collected from TL and GBL during the study period between December 2019 and November 2020
Sexes | Maturation Stages |
Resting stage (I) | |
Both sexes | The resting stage is also called inactive or undifferentiated. There is a trace of gonad development. There are slightly distinguishable differences in the follicles of females and males. The follicle is surrounded by germinal epithelium, and there are a variety of connective tissues between the follicles. A few residual spermatozoa and oocytes may be present (Figs. 4 and 5A) |
Developing stage (II) | |
Female | Oogonia are found at various developmental stages at the follicle periphery. A stalk connects the oocytes to the wall of the follicle, and they begin to fill the follicles. Some free oocytes are present in the lumen. But they constitute a smaller ratio. (Fig. 4B) |
Male | Rounded to expanded follicles are detected. Spermatogonia proliferate and give rise to several layers of spermatocytes that are expanded toward the lumen. Few spermatids are observed, and few spermatozoa are proliferated at the lumen (Fig. 5B) |
Ripe stage (III) | |
Female | Follicles are filled with mature oocytes, that have fallen in the lumen. They range in shape from rounded to elongated or irregular, and their ooplasm is filled with yolk. Lumen is barely visible. Stalked oocytes at the follicle wall have nearly vanished. (Fig. 4C) |
Male | Follicles are elongated, assuming rosette formation, and filled with spermatozoa showing their acidophilic tails as pink lines proliferate at the lumen (Fig. 5C) |
Spawning stage (IV) “The gametes are discharged. Depending on the degree of spawning, the follicles are relatively empty” | |
Female | Each follicle has a few free oocytes. Some follicles are empty, due to ova release. The follicle walls are disorganized. Connective tissue is present between the follicles (Fig. 4D) |
Male | Follicles show a streaky appearance from streaming sperm. The lumina are occupied by spermatozoa, with many gaps (Fig. 5D) |
Spent stage (V) ''Follicles appear more disorganized with broken walls, scattered, and relatively empty'' | |
Female | Connective tissue is present between the follicles. Residual oocytes are barely seen in the follicles (Fig. 4E) |
Male | Connective tissue is present between the follicles. Some follicles were empty, but others contained residual sperm with many gaps (Fig. 5E) |