The effect of processing method of Dolichos Bean (<i>Lablab purpureus</i> L. <i>Sweet</i>) on the digestibility and performance of growing-finishing pigs

Abstract

A 4 x 4 Latin square experiment was carried out using 4 bancows to investigate the effect of processing method on the digestibility of nutrients of dolichos beans and nitrogen retention in pigs. Four diets were formulated to contain the control diet with 0.09 soybean meal or 0.33 of the control diet and 0. 67 of each of either raw, boiled or roasted dolichos bean meal in diets I, II, III and IV, respectively. In another experiment, four diets were formulated such that 0. 18 of raw (Diet 2), boiled (Diet 3) or roasted (Diet 4) dolichos bean meals replaced the 0.09 soybean meal contained in the control, (Diet I). These diets were ded to 12 female and 12 castrated male pigs in a 4 x 2 factorial arrangement. Feed intake, growth performance and slaughter characteristics were evaluated. Mean values of crude protein digestability and nitrogen retention in the raw dolichos meal (50.6% and 18g/d) were relatively lower than in the processed meals (p ≤ 0.05). The corresponding values for boiled dolichos meal were higher (p < 0.05) than those of roasted meal (73.6% versus 65.2% and 12.8g/dversus 8. 7g/d). Animals fed on the raw dolichos diet (Diet 2) had significantly lower growth rates and poorer feed conversion ratio. The two parameters were improved on the animals fed on heat-treated dolichos diets. It was concluded that thermo-processing, particularly boiling greatly improved nutrient availability and overall utilisation of dolichos bean meal for pigs.

Keywords: Dolichos bean, processing, pigs, digestibility, growth

Tanzania J. Agric.,Sc. (1998) Vol. 1, No.2, 121-130