FEASIBILITY STUDY OF USING DUCKWEED AS TILAPIA-FEED INGREDIENT IN VARIOUS PROCESSING LEVELS

Duckweed has been considered a good source of dietary plant protein for fish due to its high nutritive value, up to 40% crude protein; fast growing, 8 days a generation; easy to harvest, overflow collection and other favorable production features. To assess the potential of duckweed's being used as a commercial feed ingredient, the digestibility and assimilation efficiency of the processed duckweed (also considered for storage) have to be studied. Therefore, this experiment was to find out the differences in growth performance of red tilapia fed duckweed processed in various levels.

Four experimental isoproteous diets containing duckweed processed in various levels were formulated and prepared as shown in Table 1. From simple to complicate processing of duckweed, those diets were noted as FF (fresh frozen), FD (fresh dried), DP (dried powder) and FP (fermented powder). A commercial tilapia feed was used as a reference but noted as C(control). Red tilapia (4.7±0.5g) was fed at a daily ration of 8% body weight in a 9-week duration. Little stress was from water quality or stocking density.

The results show that FP diet had the best performance in growth by WG and SGR. FF diet had the poorest feed efficiency, or FCR. No difference in survival was found. Although the processed duckweed appears improve red tilapia's rearing performance, if the net benefit is parallel to its processing cost still require an economic analysis.