Effects of feeding raw, steam-pelleted, or extruded faba bean on diet nutrient and energy digestibility and growth performance in weaned pigs

The feed value of raw, steam-pelleted, and extruded faba bean (FB) were evaluated with 208 weaned pigs (initial BW, 8.0 ± 0.79 kg), housed in 52 pens, starting 1 wk post-weaning at 21 d of age in a randomized complete block design. Faba bean was ground (2.8-mm hammer mill screen), and then part was steam-pelleted (California Pellet Mill, Crawfordsville, IN) or extruded (X115, Wenger, Sabetha, KS). After processing, FB was reground (2.8-mm screen) and included in diets (raw, steam-pelleted, or extruded) at 30% for phase 1 (d 1–14) and 40% for phase 2 (d 15–35). Diets, including a wheat-soybean meal (SBM) control diet, were formulated to provide 2.45 and 2.33 Mcal NE/kg, and 5.51 and 5.12 g standardized ileal digestible Lys/Mcal NE for phases 1 and 2, respectively. The 3 FB samples contained (DM-basis) 29.6% CP, 2.3% ether extract, 11.7% ADF, 36.3% starch, and 4.46 Mcal GE/kg. The ADFI, ADG, and G:F were measured weekly. Diet and feces were analyzed to determine diet apparent total tract digestibility (ATTD) using the indicator method. Data were analyzed using the MIXED model of SAS with diet and week as fixed effects, and block as random effect with pen as experimental unit. In phase 1, the ATTD of DM, OM, GE, CP, and DE value of wheat-SBM diet and of diets with steam-pelleted and extruded FB were similar (P > 0.05), but were 3.0–6.4% greater (P < 0.05) than those of raw FB diet. In phase 2, the ATTD of DM, OM, GE, and DE value of raw, steam-pelleted and extruded FB diets did not differ (P > 0.05), but were lower than those of wheat-SBM diet. The ATTD of CP of raw and steam-pelleted FB diets were lower (P < 0.05) than those of the wheat-SMB diet. The ATTD of CP of extruded FB diet did not differ (P > 0.05) from other diets in phase 2. Inclusion or processing of FB did not affect ADFI or ADG of pigs. Pigs fed extruded FB diet tended to have greater (P = 0.066) G:F (0.76 vs. 0.84) than pigs fed the raw FB diet in wk 1. In conclusion, steam-pelleting and extrusion increased ATTD of nutrients and energy of FB diets, but it was only reflected in increased G:F for the first week of the study.