Light and fine Structural Studies of Natural and Artificially Induced Egg Growth of Penaeid Shrimp¹

Abstract

Egg differentiation in penaeids induced to undergo gonad maturation by eyestalk ablation has been examined with light and electron microscopes. Controls consisted of both wild brown and white shrimp (Penaeus aztecus and P. setiferus) caught in various stages of ovarian maturation. These animals were sacrificed and ovarian tissues were excised and fixed in a cold (4 C) aldehyde mixture, post‐fixed in osmic acid, dehydrated in acetone, and embedded in an epoxy resin. Experimental animals included laboratory‐reared, wild immature, and wild mature animals which had resorbed ovarian tissues. These animals were ablated with hot surgical clamps and sacrificed at various time intervals. Tissues were prepared as described for the controls. The development of ova from experimental animals was compared to control animals. In the stages early oocyte, cisternal phase, platelet phase, cortical rod phase, and mature oocyte, the experimental oocytes appeared the same as the control tissues. Though further studies (e.g., biochemical and zygote development) are needed, these preliminary fine structural studies are encouraging. While ablation, a mechanical process, may not be the technique of choice for maturing shrimp, it does indicate that manipulation of the endocrine system will be successful.

Ultrastructure of differentiating oocytes and vitellogenesis in the giant freshwater prawn, Macrobrachium rosenbergii (de man)

“…The unique characteristics of Oc 1 included the presence of several prominent nucleoli and abundant Ri. These earliest stage oocytes appeared similar to those of other shrimp species, including Penaeus aztecus , Penaeu setiferus (Duronslet et al, 1975), L. vannamei (Rankin and Davis, 1990), and Penaeus mondon (Kruevaisayawan et al, 2010). The appearance of large aggregates of Ri‐like particles around the nuclear membrane, suggests that these aggregates could represent nascent Ri, which had been recently transported from the nucleus to the cytoplasm (Kruevaisayawan et al, 2010).…”

“…In Oc 3 and Oc 4, RER is well developed and tightly packed throughout the cytoplasm, suggesting that these latter stages of oocyte development are highly active in protein synthesis activity. This feature is characteristic of all vitellogenic oocytes and has been documented in lobsters (Kessel, 1968), crabs (Goudeau, 1984; Hinch and Cone, 1969), and other shrimp species (Duronslet et al, 1975). These changes are associated with an increasing level of Vg in hemolymph, which is high during the initial yolk accumulation period (Okumura et al, 2004).…”

An investigation on ovarian development of grooved shrimpMelicertus kerathurusin Izmir Bay, Turkey

“…Based on light and electron microcopy, 5 stages of oogenesis were identified in Farfantepenaeus. aztecus and Liptopenaeus setiferus (Duronslet et al, 1975), as demonstrated in a previous study with M. indicus (Subramanyam, 1965). Oka & Sirahata (1965) classified ovarian maturity in M. orientalis into 8 stages.…”

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“…In crustaceans, the morphological evidence for the uptake of extracellular yolk materials during secondary vitellogenesis has been presented for a number of species (Santana, 2002). Duronslet et al (1975) demonstrated that in the platelet phase oocytes (yolk granule stage oocytes) of P. aztecus and P. setiferus, numerous micropinocytotic vesicles which originate from the plasma membrane move into the cytoplasm and fuse each other giving rise to yolk spheres. Extraovarian yolk deposition through endocytosis has been reported in lobsters and crayfishes (Jugan and VanHerp, 1989).…”