Influence of endogenous factors on the pattern of ammonia excretion in the prawn Macrobrachium lanchesteri (deMan)

The pattern of NH3 excretion of M. lanchesteri is described in relation to its body size, variation during 24 h, and eyestalk ablation. Max. amt. of NH3 (15.99 μg​/g prawn​/day) was excreted by prawns weighing 828.1 mg and the value decreased for prawns weighing below and above this body wt. During the day, the prawns excreted max. NH3 (4.319 μg​/g prawn) between 1000 and 1400 h, whereas during the night, max. excretion (2.811 μg​/g prawn) was obsd. between 1800 and 2200 h. Bilateral eyestalk ablation steps up NH3 excretion to 26.20 μg​/g prawn​/day from 16.45μg​/g prawn​/day in normal prawns indicating that the eyestalk may have an effect in the regulation of NH3 excretion in normal prawn