Evaluation of the nutritive value of legume alternatives to soybean meal for broiler chickens.

Five experiments were conducted to investigate the nutritional value of various legumes and a faba beans processing co-product for broilers. In Expt. 1 and 3, metabolizable energy (AME) content was evaluated for 2 batches of bean starch concentrate (BSC) that differed in physical and chemical characteristics. Standardized ileal amino acid digestibility (SIAAD) was determined for BSC in Expt. 2, and for corn, soybean meal (SBM), organic and conventional faba beans, and quinoa (Expt. 4). The growth performance response of broiler chickens to partial replacement of wheat and SBM with various legumes was investigated in Expt. 5. The AME of the BSC assayed in Expt. 1 was lower (P < 0.01) than that of the BSC assayed in Expt. 3. The SIAAD was generally high for BSC in Expt. 2 although the content and digestibility of sulfur amino acids were low. In Expt. 4, there was no difference in SIAAD of Arg, Phe, Asp, and Gly among the different feedstuffs assayed. SIAAD was largely similar for both conventional and organic faba bean. The SIAADs of Met, Thr, Ser, and Tyr were lower (P < 0.05) for quinoa compared with SBM or corn. In Expt. 5, FCR was greater (P < 0.05) for broiler chickens receiving faba beans+barley mix or lupins compared with the wheat-SBM control diet. Amino acid digestibility was greater (P < 0.01) for the diets containing lupins compared with the other diets except for Lys, Met, Thr, Ala, Asp, and Ser. On the other hand, amino acid digestibility in diet with faba beans+barley mix was lower (P < 0.05) compared with all the other diets, except for Arg, Asp, Lys, and Thr. It was concluded from the current studies that there is scope for using the assayed legumes, co-products, and quinoa in broiler chickens to partly replace SBM as protein feedstuffs.