PSVIII-3 The functional properties and digestibility of round and wrinkled pea flour in swine diets

Abstract Wrinkled and round pea flour display physical and compositional differences. Wrinkled peas have reduced activity of the starch branching enzyme, which decreases amylopectin production. As a result, wrinkled peas have an increased proportion of amylose, relative to round peas. The rate and extent of starch digestion are influenced by the ratio of amylose to amylopectin in starch. Extrusion results in swelling of the starch, altering the crystalline structure. The objective of this study was to determine the role of the amylose to amylopectin ratio and extrusion on starch digestibility and microbial characteristics in growing pigs. Ileal-cannulated barrows (n = 8) with an initial body weight (BW) of 40 ± 1 kg were randomly assigned to 1 of 4 dietary treatments (n = 8 pigs/treatment) in a replicated Latin square design with four blocks. Dietary treatments were round pea flour (RPF), extruded round pea flour (RPF-E), wrinkled pea flour (WPF), and extruded wrinkled pea flour (WPF-E). The starch content decreased in the native WPF (36.7%) and WPF-E (34.7%) compared with RPF (50.1%) and RPF-E (49.1%). However, the amylose content in native WPF (77.1%) and WPF-E (70.7%) was greater compared with RPF (40.1%) and RPF-E (39.8%). Ileal digestibility of starch differed between pea flours (P < 0.05), greatest for RPF (92.8%) and RPF-E (92.2%) and least for WPF (80.2%) and WPF-E (76.7%). Total tract digestibility was least for RPF (98.7%) compared with other treatments (P < 0.05). Total tract digestibility of starch was greatest with RPF-E compared with RPF (99.5% vs 98.7%, P < 0.01) but was not different from WPF (99.25%) or WPF-E (99.51%). Shannon index, an indicator of microbial diversity, decreased in ileal digesta of WPF-E-fed pigs compared with RPF-E (P < 0.05) but similar among treatments in the feces. In summary, compared with WPF or WPF-E, RPF and RPF-E had reduced amylose content and greater starch digestibility determined at the end of the ileum; however, total tract digestibility of starch was similar among all treatments. Furthermore, RPF-E compared with RPF, WPF, and WPF-E increased microbial diversity in the ileal digesta, but no difference among treatments in the feces.