In vitro manipulation of egg activation in the open thelycum shrimp Litopenaeus

This research was designed to develop a basis for the in vitro manipulation of egg activation in Litopenaeus. The timing and sequence of events associated with egg activation of three species of Litopenaeus: L. occidentalis, L. stylirostris, and L. vannamei are described. Spawning in cold seawater (21.5 °C) induces a significant delay in cortical rod release as well as in hatching envelope formation. Magnesium concentration at 318.8 and 5.2 mg l− 1 did not induce any detectable variation in egg activation. In vitro availability of unfertilized eggs was accomplished by dissecting ovaries at the time of spawning; a latency period in dry conditions from 1 to 10 min induced no detrimental effect on initiation of egg activation. In addition, an in vitro assay for evaluating interspecific and intraspecific primary binding among species of Litopenaeus is presented.