Utilization of Feed and Growth Performance of Mud Crabs: The Effect of Herbal Extracts as Functional Feed Additives

This study aimed to analyze the effect of herbal extracts as functional feed additives on the utilization of feed and growth performance of orange mud crabs (Scylla olivacea). The test animals used were 60 crabs for each treatment dose. The crabs are kept individually in a crab box which was placed on a floating bamboo raft. This was to enable floating on the surface of the pond water which had a depth of ±80 cm. The treatments tested were four doses of a combination herbal extract from Morus alba, Curcuma xanthorrhiza, and Boesenbergia rotunda, namely 0, 200, 400, 600 mg kg-1 of feed. Formulated feed with the protein content of 41.93%, fat 7.43%, Nitrogen Free Extract (NFE) 29.33%, and crude fiber 7.82% was given at a dose of 5% body weight every day. Based on one-way ANOVA, the results showed that the dose of herbal extracts influences the feed utilization and growth performance of mud crabs. The dose of herbal extract 600 mg kg-1 of feed provided higher feed utilization and growth performance (LSD Test: P<0.1). Significant differences were found between feed utilization and growth performance of mud crabs after molting and non-molting. In molting mud crabs, treatment with herbal extract 600 mg kg-1 obtained an average weight gain of ±60.73 from the initial weight, compared to control crabs (without herbal extracts) gaining an average weight gain of ±43.73%. However, in non-molting crabs, ±5.44 and ±6.42 weight gain was observed, respectively. Significant differences also occurred between treatments for specific growth rates, feed consumption, feed efficiency, and condition factors. These results provided information that herbal extracts are potentially as feed additives to increase feed utilization and growth performance, as well as stimulate molting in crab cultivation.