title: Nutritional value for swine of extruded corn and corn fractions obtained after dry milling.
abstract: The experiment was designed to assess whether corn fractions or extrusion of corn can result in feed ingredients with a greater nutritional value than corn. Corn grain (8.0% CP, 0.21% P, 9.8% NDF) was processed by extrusion (82.8 degrees C, 345 kPa steam pressure for 12 s) or by dry milling to derive fractions rich in germ (13.1% CP, 1.19% P, 17.2% NDF), hulls (8.1% CP, 0.27% P, 32.6% NDF), and endosperm, namely tails (6.6% CP, 0.07% P, 3.6% NDF) and throughs (7.4% CP, 0.15% P, 4.5% NDF). Relative recovery in each fraction was 16, 20, 44, and 20%, respectively. Ileal digestibility of DM, P, and amino acids was determined using diets containing 7.0% CP from soybean meal and 5.3% CP from one of the test products. To allow for determination of standardized ingredient, ileal digestibility, basal endogenous AA losses were determined using a protein-free diet (74.6% cornstarch and 18.7% sucrose). Soybean meal ileal digestibility was determined using a diet (12.3% CP) based on soybean meal (23.3%). Eight barrows (27 +/- 2 kg) fitted with T-cannulas were fed 8 experimental diets (5-d adaptation and 2-d collection period) such that each diet was evaluated in at least 5 barrows. Relative to corn (77.9 +/- 1.2%), ileal digestibility of DM was greater for extruded corn (82.5%; P = 0.02), tails (85.9%; P < 0.01), and throughs (85.0%; P < 0.01), but it was lower for hulls (62.2%; P < 0.01) and germ (51.1%; P < 0.01). For P, corn (41.6 +/- 9.5%), throughs (47.2%), and hulls (57.3%) had similar ileal digestibility, but germ (7.9%) had lower ileal digestibility (P = 0.02) than corn; tails (27.6%) and extruded corn (23.5%) were not different from corn or germ but were lower than throughs and hulls. For total AA, corn (84.7 +/- 2.4%), throughs (84.3%), and hulls (85.8%) had similar ileal digestibility, but germ (76.6%) had lower ileal digestibility (P < 0.01) than corn; tails (82.0%) and extruded corn (81.7%) were intermediate. In conclusion, germ and hulls have a low ileal DM digestibility; germ also has low AA and P digestibility. Extrusion improved the ileal DM digestibility of corn. To maximize the ileal digestibility, removal of germ and hull from corn or extrusion of corn may thus be of interest.
authors.affiliation: Department of Animal Science and Interdepartmental Nutritional Program, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: N S
authors.initials: NS
authors.lastname: Muley
authors.forename: E
authors.initials: E
authors.lastname: van Heugten
authors.forename: A J
authors.initials: AJ
authors.lastname: Moeser
authors.forename: K D
authors.initials: KD
authors.lastname: Rausch
authors.forename: T A T G
authors.initials: TA
authors.lastname: van Kempen
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004044:Dietary Proteins / Q000032:analysis*; D004063:Digestion; D005511:Food Handling / Q000379:methods*; D008297:Male; D009751:Nutritional Requirements; D009753:Nutritive Value; D010316:Particle Size; D013552:Swine / Q000254:growth & development / Q000378:metabolism*; D003313:Zea mays / Q000737:chemistry
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins