Standardized ileal digestibility of amino acids and apparent metabolizable energy in corn and soybean meal for organic broiler chicken production in Ontario

Abstract

Standardized ileal digestibility (SID) of amino acids (AA) and apparent metabolizable energy corrected for nitrogen (AMEn) in samples of organic corn and soybean meal (SBM) were determined. Conventional corn (CC) and SBM (CSBM) samples were tested for comparison. A total of 560, fourteen-day-old male broiler chickens (Cobb 500) were weighed, placed in cages (10 birds per cage), and allocated to seven (n = 8) semi-purified wheat-starch-based diets. Diets were (1) CC, (2) imported organic corn, (3) local organic corn, (4) CSBM, (5) imported organic SBM (OSBMI), (6) local organic SBM (OSBML), and (7) nitrogen-free wheat starch. Only few differences were observed on SID of AA; SID of lysine was lower (P = 0.002) in organic corn samples relative to CC, and SID of methionine was lower (P = 0.002) in OSBML sample relative to CSBM and OSBMI samples. The AMEn of CC was higher (P < 0.01) than that of organic corn samples. The AMEn of OSBML was higher (P < 0.001) than for CSBM and OSBMI; however, the value for OSBMI was higher (P < 0.001) than for CSBM. In conclusion, utilization of AA in conventional and organic feedstuffs was comparable; however, differences in energy utilization warrant considerations in organic broiler feed formulation.