Digestibility of dried and toasted peas in pigs .2. Ileal and total tract digestibilities of amino acids, protein and other nutrients

Two experiments in which pigs were fed dried or toasted peas (Pisum sativum var. Solara) from 2 years of harvest were performed. Diets with peas as the sole source of nitrogen were formulated to contain approximate to 170 g kg(-1) crude protein (CP). Toasting applied in the present conditions (moisture content approximate to 150 g kg(-1), 130 degrees C, 3-4 min) did not damage the lysine of the peas. The animals were fitted with a T-shaped cannula at the end of the ileum, and two balances with ileal and faecal collections were carried out. When peas from one of the harvests (Experiment 1) were fed, the ileal digestibility of most amino acids was increased by toasting; the digestibility of dry matter (DM) increased from 69.4 to 76.1%, the digestibility of energy from 71.2 to 77.2%, and the same tendency (P = 0.16) was observed for protein digestibility. When peas from the other harvest (Experiment 2) were fed, no effect of toasting was observed on the ileal digestibilities of nutrients. DM (P = 0.16) and energy (P = 0.12) digestibilities showed tendencies for lower values after toasting. At total tract level, digestibilities were higher than at ileal level, and no effect of heat treatment on the digestibilities of nutrients was observed in either of the two experiments. It was concluded that toasting applied under specified conditions (moisture content = 150 g kg(-1), 130 degrees C, 3-4 min) can improve the ileal digestibility of peas. However, harvests of different years can show different digestibilities and heat treatment can affect them unequally. Therefore, conclusions should be drawn with caution.