The Effect of Unilateral and Bilateral Eyestalk Ablation on Haemolymph Osmotic and Ionic Regulation and Gill Na+, K+-atpase Activity In Marsupenaeus Japonicus (bate, 1888) (Decapoda, Natantia)

Abstract

The effects of eyestalk ablation on osmotic and ionic regulation and Na + , K + -ATPase activity of Marsupenaeus japonicus were investigated in a period of 24 hrs. The osmolarity, potassium, and calcium concentration were high in the shrimps treated bilaterally, intermediate in the shrimps that were treated unilaterally, and low in the intact shrimps, while all those values of eyestalk ablated shrimps increased with increasing treatment time. However, the haemolymph sodium and chloride concentra- tion of eyestalk ablated shrimps were lowered, and also decreased further with increasing treatment time. The bilaterally and unilaterally ablated shrimps had higher total ATPase and Na + , K + -ATPase activities in the gills than the intact shrimp, and the ATPase activities of the ablated ones were raised with increasing treatment time up to 16 hrs. Therefore, eyestalk ablation of shrimps causes changes in the osmotic and ionic regulation, and also affects the Na + , K + -ATPase activity of the gills. Les effets de l'ablation du pedoncule oculaire sur la regulation osmotique et ionique et sur l'activite de la Na + , K + -ATPase de Marsupenaeus japonicus ont ete etudies sur une periode de 24 heures. L'osmolarite, la concentration en potassium et en calcium etaient elevees chez les crustaces traites bilateralement, intermediaire chez ceux traites unilateralement et faible chez les non traites, et chez les crevettes ayant subi une ablation complete, toutes ces valeurs augmentaient avec la duree du traitement. Cependant, le sodium de l'hemolymphe et la concentration en chlorures chez les specimens prives de pedoncule oculaire avaient diminue et ce encore plus lorsque la duree du traitement etait prolongee. Les crustaces traites bilateralement, et ceux traites unilateralement avaient des activites d'ATPase totale et de Na + , K + -ATPase plus elevees dans les branchies que les non traites, et les activites d'ATPase des specimens traites augmentaient avec la duree de traitement, jusqu'a 16 heures. Ainsi, l'ablation des pedoncules oculaires chez ces crevettes provoque des modifications de la regulation osmotique et ionique, et affecte egalement l'activite de la Na + , K + -ATPase des branchies.