139 Digestibility of phosphorus in heat-treated dry extruded-expelled soybean meal and solvent-extracted and expeller-extracted canola meal fed to growing pigs

Abstract

Although heat treatment affects digestibility of amino acids in feed ingredients, there is less information as to whether such an effect also applies to minerals. Therefore, the objective of this research was to investigate the effects of heat treatment on apparent (ATTD) and standardized total tract digestibility (STTD) of P in dry extruded-expelled soybean meal (DESBM), solvent-extracted canola meal (SCM), and expeller-extracted canola meal (ECM) fed to growing pigs. A total of 36 pigs (19.0 ± 1.0 kg) were assigned to 1 of 6 diets in a completely randomized design to give 6 replicates per diet. Pigs were individually housed in metabolism crates for 12 d, including 7 d for adaptation and 5 d for total collection of feces. The experimental diets were formulated to contain non-heated or heat-treated DESBM, SCM, and ECM as the sole source of P. Pigs were offered their daily ration at 2.8 times their maintenance energy requirement. Data were analyzed as a 3 × 2 factorial arrangement using the PROC MIXED of SAS with ingredients, heat treatment, and their interaction; however, no interaction was observed for any variable. Pigs fed the DESBM diet had a higher (P < 0.05) ATTD and STTD of P than pigs fed SCM and ECM diets. The ATTD and STTD of P in heat treated samples were higher (P < 0.05) than in non-heated samples. In the heat-treated samples, the values of STTD of P were 49.4, 23.2, and 25.8% for DESBM, SCM, and ECM, respectively. Respective values for STTD of P in non-heated DESBM, SCM, and ECM were 48.5, 20.2, and 22.5%. The ATTD of Ca in non-heat-treated samples was lower (P < 0.05) compared to the values for heat-treated samples. In conclusion, heat treatment increased ATTD and STTD of P in DESBM, SCM, and ECM fed to growing pigs.