Du Thanh Hang, 2013. Livest. Res. Rural Dev., 25 (6): 101

Forty-five Luong Phuong chickens at 30 days of age were randomly distributed into 3 replications of five treatments (3 chickens per experimental unit). The birds were offered a basal diet based on maize and soybean meal (16% crude protein in the DM) offered ad libitum or restricted to 60, 70, 80 or 90% of the ad libitum intake. On all the diets the birds had free access to fresh duckweed. When the concentrate was freely available, the chickens consumed fresh duckweed in amounts equivalent to 7% of the total DM intake and 15% of the total protein intake, giving a protein content in the diet DM of 17.5%. These proportions increased to 15 and 30%, for DM and protein, respectively, and the overall protein content of the diet increased to 19.4%, when the concentrate offer level was reduced to 60% of ad libitum intake. Feed DM intake, live weight gain and feed DM conversion became poorer as the proportion of duckweed in the diet increased, and there was no saving in concentrate usage per unit live weight gain. Under the conditions of the present study, with a basal diet of maize and protein concentrate (16% protein in DM), there was no advantage in restricting the intake of the concentrate and providing ad libitum duckweed, as the chickens were unable to eat enough fresh duckweed to compensate for the restriction in the concentrate allowance.