Energy and amino acid digestibility of raw, steam-pelleted and extruded red lentil in growing pigs

Abstract

Lentil is an alternative feedstuff providing both starch and protein with a lower energy and amino acid (AA) digestibility in pigs than conventional feedstuffs. However, heat processing may increase the digestibility of energy and AA and thereby increase the nutritive value of lentil. Therefore, a study was conducted to test effects of steam-pelleting and extrusion of lentil on digestible energy (DE) and calculated net energy (NE) values and AA digestibility in growing pigs. Three diets containing 956 g/kg of either raw, steam-pelleted (80–85 °C) or extruded (115 °C) lentil were fed to 9 ileal-cannulated growing pigs (initial body weight = 69.0 ± 6.7 kg) at 2.8 × maintenance DE in a triplicate 3 × 3 Latin square with 3 periods. An N-free diet was fed to all pigs to measure basal endogenous losses of AA at the start of the trial. Each 9-day period comprised sequentially of a 5-day adaptation, 2-day faecal collection and 2-day ileal digesta collection. Steam-pelleting and extrusion increased (P < 0.05) the coefficient of apparent total tract digestibility (CATTD) of dry matter (DM), gross energy (GE) and crude protein (CP) of lentil, and increased (P < 0.05) the calculated NE values of lentil grain. Steam-pelleting or extrusion increased (P < 0.05) the coefficients of standardised ileal digestibility (CSID) of CP and AA. In conclusion, heat processing can increase the digestibility of AA and the energy value of lentil in growing pigs that may increase the use of lentil as alternative feedstuff for pigs. Among heat processing methods, steam pelleting would be sufficient to achieve increased DE and calculated NE values and CSID of AA of lentil.