title: Effect of increased heat processing and particle size on phosphorus bioavailability in corn distillers dried grains with solubles.
abstract: Previous studies have reported that increased heat processing and feeding larger particle size ingredients may increase the bioavailability of phytate P in some feedstuffs. Therefore, one chick experiment was conducted to determine the effect of various increased heat processing treatments on bioavailability of P in corn distillers dried grains with solubles (DDGS), and 2 chick experiments were conducted to determine the effect of particle size on bioavailability of P in DDGS. In addition, one precision-fed cecectomized rooster assay was conducted to evaluate the effects of increased heating on amino acid digestibility. For the chick experiments, a P-deficient cornstarch-dextrose-soybean meal basal diet containing 0.10% nonphytate P was supplemented with 0.0, 0.05, or 0.10% P from KH(2)PO(4) or 1 of 2 levels of DDGS. Diets were fed from 8 to 22 d of age, and P bioavailability relative to the P in KH(2)PO(4) was estimated using the standard curve or slope-ratio methods with tibia ash as the response variable. Increased heating of DDGS by autoclaving at 124 kPa and 121 degrees C for 60 to 80 min or by heating in a drying oven at 121 degrees C for 60 min significantly increased relative P bioavailability in DDGS (from 70 to as high as 91%) in several treatments. Amino acid digestibility, however, was greatly reduced by increased heating in most cases, particularly for Lys. Relative bioavailability of P was not significantly affected by DDGS particle sizes ranging from 542 to 837 microm. Our results indicated that increased heating of DDGS increased bioavailability of P but decreased digestibility of amino acids, particularly Lys, and that bioavailability of P was not affected by particle size.
authors.affiliation: Department of Animal Sciences, 1207 W. Gregory Dr., University of Illinois, Urbana, IL 61801, USA.
authors.forename: C Martinez
authors.initials: CM
authors.lastname: Amezcua
authors.forename: C M
authors.initials: CM
authors.lastname: Parsons
mesh_terms: D000220:Adaptation, Biological; D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004032:Diet / Q000662:veterinary; D004063:Digestion; D005511:Food Handling / Q000379:methods*; D006358:Hot Temperature; D010758:Phosphorus / Q000378:metabolism*; D003313:Zea mays / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010758:Phosphorus