Effect of a modified earthworm formulated feed (MEF) on the growth and development of juvenile giant freshwater prawns Macrobrachiumrosenbergii.

Abstract

The use of commercial feeds for prawn aquaculture constitutes a significant investment amounting to approximately 40-60% of the total cost of operations (Mitra et al., 2005). This study aims to describe the effects of a modified earthworm-formulated feed (MEF) on the growth and development of juvenile M. rosenbergii prawns by comparing it to a brand of commercial feed. Two aquaria for the experiment (each with 39 prawns) were used: one was fed with modified earthworm formulated feed (MEF) and the other fed with the commercially-formulated feed (CF). Data was collected every week for 7 weeks, namely weight, length, width, survival. There was a slow but steady increase in the values of the weight, length and width of both treatments. The initial and final values of the two treatments for weight are 0.677g-1.902g for CF and 0.408g-1.294g for MEF, for length 48.699mm-60.028mm for CF and 38.046mm-51.028mm for MEF, lastly for width 7.791mm-10.399mm for CF while 6.224mm-8.639mm for MEF respectively. The CF feed fed prawns achieved significant gain in weight, length and width earlier compared to MEF-fed prawns. However, the differences in growth rate between the two test groups were not significant. The survival rate for the CF feed fed prawns was 79% while for MEF- fed prawns was 74%. Both survival rates were similar to the observed survival rates of Abdel-Hakim et al. (2013). In both test groups, behaviors observed such as preening, territoriality, zoning of available space, lack of communal interaction and isolation from other prawns revolved around the prawns exhibiting intraspecific competition for the limited resources. These behaviors observed were similar with those of Saravanan et al (2008).