Four ruminally fistulated Thai native bulls with average body weight (BW) of 263 ±10 kg
were randomly assigned according to a 4 x 4 Latin Square Design. Each animal was kept in
an individual pen and received free access to water. Plicatulum hay (Paspalum plicatulum
Michx.) was offered to each animal ad libitum with 0.50 kg/h/d of soybean meal. The dietary
treatments were SPP supplementation at 0, 0.25, 0.50 and 0.75 % of their BW (T
1, T
2, T
3
and
T4
, respectively).