Ngamsaeng et al., 2004. Livest. Res. Rural Dev., 16 (3): 16

A feeding trial was carried out to evaluate the protein quality in water spinach or duckweed alone or mixed when included in a basal diet of broken rice for growing Muscovy ducks. There were three treatments, consisting in diets given ad libitum to 24 ducks: WS, water spinach plus broken rice (80:20 fresh basis); DW, duckweed plus broken rice (80:20 fresh basis) and MWD, water spinach and duckweed plus broken rice (35:45:20 fresh basis). Total DM intake and total N*6.25 intake were highest for duckweed as the only supplement. Lowest values were with water spinach, with the mixed supplement (MWD) showing intermediate values. Average daily gain was highest for ducks fed diet DW (22.4 g/bird/day) and lowest when fed diet WS (6.2 g/bird/day). The growth rate of ducks was linearly related to total N*6.25 intake (R 2=0.89). Feed conversion was poorer for diet WS and MWD compared with DW (9.1, 4.3 and 3.8 g DM/gain for diet WS, MWD and DW respectively). It can be concluded that growth rate of ducks can be used to assay the protein quality from vegetables. Total DM intake, total N*6.25 intake, live weight gain and feed conversion were better when the ducks were fed duckweed rather than water spinach as a supplement to broken rice.