Two studies were conducted to determine the impact of supplementation of diets containing ensiled cassava leaves as the main
protein source with synthetic
amino acids, DL-
methionine alone or with
L-lysine. In study 1, a total of 40 pigs in five units, all cross-breds between Large White and Mong Cai, with an average initial
body weight of 20.5 kg were randomly assigned to four treatments consisting of a basal diet containing 45% of dry matter (DM) from ensiled cassava leaves (ECL) and ensiled cassava root supplemented with 0%, 0.05%, 0.1% and 0.15% DL-
methionine (as DM). Results showed a significantly improved performance and
protein gain by extra
methionine. This reduced the feed cost by 2.6%, 7.2% and 7.5%, respectively. In study 2, there were three units and in each unit eight cross-bred (Large White × Mong Cai) pigs with an initial
body weight of 20.1 kg were randomly assigned to the four treatments. The four diets were as follows: a basal diet containing 15% ECL (as DM) supplemented with different amounts of
amino acids L-lysine and DL-
methionine to the control diet. The results showed that diets with 15% of DM as ECL with supplementation of 0.2%
lysine +0.1% DL-
methionine and 0.1%
lysine +0.05% DL-
methionine at the 20-50 kg and above 50 kg, respectively, resulted in the best performance,
protein gain and lowest costs for cross-bred (Large White × Mong Cai) pigs. Ensiled cassava leaves can be used as a
protein supplement for feeding pigs provided the diets contain additional amounts of synthetic
lysine and
methionine.