Author(s): Dr. T Suguna

Abstract: Macrobrachium lamerrii passes through four larval stages and a juvenile stage before metamorphosing into the adult prawn. The larvae undergo six to eight molts during development before metamorphosis to the adult stage. Various physiological activities such as molting and reproduction are controlled by Neuroendocrine centres like eyestalk, brain and thoracic ganglion. Exposure of the larvae to extracts of eyestalks, brain, or thoracic ganglia brought about significant alternations in the molt frequency. The extracts of the brain and thoracic ganglia reduced the duration of the intermolt period while eyestalk extracts increased the intermolt duration. It was further observed that exposure of larvae to extracts of brain and thoracic ganglia brought about increase in size and weight of the larvae. So the eyestalk of M. Lamerrii is found to be composed of growth inhibiting hormones where as thoracic ganglion and bra in are composed of molt / growth accelerating hormones. The hormones of the adult Macrobrachium lamerrii are also found to be more potential than that of the juvenile M. Lamerrii.

Pages: 31-33  |  604 Views  92 Downloads

Download Full Article: Click Here