The enhancement of the nutritive value of peas for broiler chickens: An evaluation of micronization and dehulling processes

The effects of dehulling and micronization (infrared heating) on the nutritive value of three cultivars (Impala, Radley, and Sirius) of peas (Pisum sativum) varying in coat color for broiler chickens were studied. Dehulling increased (P less than or equal to 0.05) protein and starch contents and decreased (P less than or equal to 0.05) fiber content of peas. Also, the concentrations of most amino acids slightly increased (P greater than or equal to 0.05). Micronization slightly changed (P greater than or equal to 0.05) the chemical composition of peas. Moisture, protein, fiber and phosphorus contents marginally decreased. The concentrations of aspartic acid, glutamic acid, isoleucine, lysine, cystine, threonine, and tyrosine decreased (P less than or equal to 0.05), whereas that of methionine slightly increased (P greater than or equal to 0.05). Lysine concentration was decreased by 2.7%. The TME(N) and average true AA availability values determined with adult cockerels were improved (P less than or equal to 0.05) by micronization, but the availabilities of lysine were decreased by 11.3, 4.4, and 2.0% for Impala, Radley and Sirius, respectively. The decrease was significant (P less than or equal to 0.05) for Impala and Radley but not significant for Sirius peas. Application of micronization resulted in a significant (P less than or equal to 0.05) improvement in AME(n), apparent protein digestibility (APD), and starch digestibility. The increments ranged from 19.4 to 31.3, 8.5 to 33.6, and 12.2 to 22.3% for AME(n), APD, and starch digestibility, respectively. In contrast, dehulling had little or no effect on AME(n) (3.0 and 4.9%), APD (-1.8 and -4.2%) and starch digestibility (2.0 and 1.3%) values of Impala (yellow-seeded) and Radley (green-seeded) peas but significantly (P less than or equal to 0.05) improved the AME(n) (24.1%), APD (26.8%), and starch digestibility (12.1%) values of Sirius (brown-seeded) peas. Chick performance was evaluated in a 2-wk trial. Birds fed micronized peas grew faster and had better feed conversion (P less than or equal to 0.05) than birds fed untreated peas and the wheat-soybean control diet. Addition of lysine to the diet containing micronized peas further improved (P greater than or equal to 0.05) weight gains and feed conversion of broiler chicks. Dehulling only improved (P less than or equal to 0.05) the performance of birds fed Sirius peas.