Evaluation of different maze systems for the determination of feed attractability for longarm river prawn Macrobrachium tenellum

Previous studies have shown that crustacean feed attractability has an enormous importance, because the consumption, quality and feed conversion rate can be improved, by reducing the time of residence pre-ingestion and the leaching of nutrients. For this reason, different protocols and methods has been developed to measure feed attractability. This study evaluated the use of maze type Y, and rectangular systems to determine the attractant power of a commercial feed on longarm river prawn Macrobrachium tenellum. The Y type maze system without barriers, and with three different types of barriers (with or without access to the area where a commercial feed) was evaluated. Ten prawns were placed in the acclimation chamber of the system at 28[degrees]C for 60 min before the start of the experiment. To start the test, commercial feed (20% of prawn biomass) was placed into the system feeding area, then the acclimation chamber was open to allow for the free prawn movement, evaluating the feed attractability by measuring the time for the first "hit", total number of hits, and the number of prawns which entrances to the feeding area during 15 min. Similar tests were performed with a rectangular type maze system, comparing the atractability results obtained in both systems. The results presented here highlight the importance of the genus behavior and the selection of protocols and systems, as well as the materials used in its maze system construction, for attractability testing inM. tenellum.