Detection of prostaglandin E2 in polychaete Perinereis sp and its effect on Penaeus monodon oocyte development in vitro

Prostaglandins are involved in the reproductive processes in a variety of animals, including crustaceans. It was found that polychaetes, the best maturation diet for shrimp broodstock, possessed the greatest variation of prostaglandin E-2 (PGE(2)) when compared with other live feeds. The level of PGE(2) varied according to sizes, feed intake, sources and type of polychaete. The matured and also larger sand polychaete Perinereis sp. contained higher PGE2 levels than younger and smaller sand polychaetes (18.16 +/- 5.82 ng PGE(2) mg(-1) protein for polychaetes at an average length of 10 cm up to 160.8 +/- 37.09 ng PGE(2) mg(-1) protein for polychaetes at an average length of 17 cm). The PGE(2) levels in ovaries and haemolymph of female shrimp fluctuated with the developmental stage of the ovaries. The highest concentration of PGE(2) in haemolymph was at stage 3 of ovarian development, whereas the highest concentration of PGE(2) in shrimp ovaries was at stage 4. In vitro incubation of Penaeus monodon pre-vitellogenic oocytes with polychaete extract and synthetic PGE(2) demonstrated that both PGE(2)s enhanced oocyte development, especially during late development and ovulation. The putative role of PGE(2) from polychaetes or the presence of PGE(2) in polychaetes may be a factor in their role as a dietary constituent required for shrimp oocyte development.