title: The impacts of hammer-mill screen size and grain particle size on the performance of broiler chickens offered diets based on two red sorghum varieties.
abstract: 1. The two red grain sorghums were extensively characterised. Kafirin, polyphenolic compounds, free, conjugated and bound phenolic acids, phytate concentrations and starch pasting profiles were determined. 2. The experiment consisted of a 2 × 4 factorial array of dietary treatments comprising two red sorghum varieties (Tiger and Block I) ground through 4 hammer-mill screen sizes (2.0, 3.2, 4.8 6.0 mm) prior to incorporation into nutritionally equivalent diets. Eight steam-pelleted dietary treatments were each offered to 7 replicates (6 male Ross 308 birds per cage) from 7 to 28 d post-hatch. 3. Effects of dietary treatments on growth performance, relative gizzard and pancreas weights, nutrient utilisation, apparent starch and protein (N) digestibility coefficients and disappearance rates from 4 small intestinal segments were determined. 4. The 2.0-mm hammer-mill screen generated an average geometric mean particle size of 794 μm and the 6.0-mm screen a mean particle size of 1405 μm. However, hammer-mill screen size did not influence weight gain or FCR. The 6.0-mm screen size generated significantly higher starch and protein (N) digestibility coefficients in the distal jejunum and distal ileum than the 2.0-mm hammer-mill screen. 5. Tiger sorghum was superior to Block I sorghum, as significant advantages were observed for feed conversion ratios (3.25%), AME (0.37 MJ), ME:GE ratios (4.15%), AMEn (0.53 MJ), distal ileal starch digestibility coefficients (2.46%) and protein (N) digestibility coefficients in the distal jejunum (4.66%), proximal ileum (1.96%) and distal ileum (2.16%). The inferior Block I sorghum contained more kafirin (67.1 versus 51.3 g/kg), phytate (9.79 versus 8.40 g/kg), total phenolic compounds (4.68 versus 4.12 mg GAE/g), flavan-4-ols (7.98 versus 5.04 ABS/ml/g), total phenolic acids (554 versus 402 μg/g) and total ferulic acid (375 versus 281 μg/g) in comparison to Tiger sorghum.
authors.affiliation: a Poultry Research Foundation, Faculty of Veterinary Science , The University of Sydney , Camden , Australia.
authors.forename: P H
authors.initials: PH
authors.lastname: Selle
authors.affiliation: a Poultry Research Foundation, Faculty of Veterinary Science , The University of Sydney , Camden , Australia.|b Poultry CRC , University of New England , Armidale , Australia.
authors.forename: H H
authors.initials: HH
authors.lastname: Truong
authors.affiliation: c Department of Plant and Food Sciences, Faculty of Agriculture and Environment , The University of Sydney , Sydney , Australia.
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-1774-0000
authors.initials: A
authors.lastname: Khoddami
authors.affiliation: a Poultry Research Foundation, Faculty of Veterinary Science , The University of Sydney , Camden , Australia.
authors.forename: A F
authors.initials: AF
authors.lastname: Moss
authors.affiliation: c Department of Plant and Food Sciences, Faculty of Agriculture and Environment , The University of Sydney , Sydney , Australia.
authors.forename: T H
authors.initials: TH
authors.lastname: Roberts
authors.affiliation: a Poultry Research Foundation, Faculty of Veterinary Science , The University of Sydney , Camden , Australia.
authors.forename: S Y
authors.initials: SY
authors.lastname: Liu
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D002523:Edible Grain / Q000502:physiology*; D008297:Male; D000078622:Nutrients / Q000502:physiology*; D010316:Particle Size; D045868:Sorghum / Q000737:chemistry* / Q000235:genetics
chemical_list: D000078622:Nutrients