Determination of standardized ileal digestibility of crude protein and amino acids and digestible indispensable amino acid score of faba beans, lentils, and yellow peas fed to growing pigs

The objective of this study was to determine the standardized ileal digestibility (SID) of protein and amino acids (AA) and calculate the digestible indispensable AA score (DIAAS) of three varieties of Canadian grown pulses (faba bean, lentil, and yellow pea). Three steam-pelleted (80 °C) diets (faba/lentil/pea; 40% inclusion) and a nitrogen-free diet were fed to eight cannulated growing pigs in a 4 × 4 replicated Latin square design. The SID values were used to calculate DIAAS. There were no differences in SID of protein and AA when all diets were compared (P > 0.05). The SID of methionine was 95% for faba beans, 96% for lentils, and 96% for peas. The SID of lysine was 93% for faba beans, 92% for lentils, and 90% for peas. Tryptophan had the lowest SID across all indispensable AA of all pulses (59% faba, 61% lentil, and 41% pea). All other indispensable AA SID were above 80%. Tryptophan was the limiting indispensable AA for all pulses as determined by DIAAS, with scores of 30 (faba), 57.83 (lentil), and 27.27 (pea). These values will aid in optimal inclusion of steam-pelleted pulses in diets for swine and provide an insight on the protein quality of pulses for humans.