Résumé
The study was conducted to evaluate digestibility of some aquatic plants by giant gourami (Osphronemus goramy). The apparent digestibility of four aquatic plants Azolla sp. (AZ), duckweed (Lemna sp.) (DW), water hyacinth (Eichhornia crassipes) WH) and Salvinia sp. (SA) were examined using the diet substitution method and yttrium oxide as the inert marker. Each raw material was examined in triplicate and faecal material was collected from fish using manual siphoning techniques. All raw materials were tested at 30%. The reference diet was primarily composed of fishmeal (FM), soybean meal (SM) and meat and bone meal (MBM). The study was carried out using giant gourami with initial weight 15, 8 g fish-1 at stocking density 30 fish aquarium-1. The aquaria was equipped with aeration and thermostat. All the plants were tested in dry meal form. The result showed that AZ and DW have the best value for total (78.22 and 76.23%) and protein digestibility (71.63 and 70.09%) respectively. From digestibility stand of view, AZ and DW can be a good candidate as alternative source of feed for giant gourami juveniles and propose these macrophyte as a possible way to promote ecological intensification in small scale aquaculture for this fish in IMTA system.