title: Evaluation of the compositional and nutritional values of phytase transgenic corn to conventional corn in roosters.
abstract: Three experiments were conducted to evaluate the compositional and nutritional values of corn grains [phytase transgenic corn (PTC) and isogenic conventional corn (CC)] and compare the efficacy of corn-based phytase and extraneous microbial phytase for enhancing the utilization of phytate phosphorus (P) in single corn or corn-soybean mixed meals (corn:soybean = 2.5:1, wt:wt) fed to roosters. Following a 48-h fasting period, 16 roosters were given 50 g of each sample via crop intubation and excreta were collected for 48 h. Nitrogen-free and phosphorus-free diets were used to evaluate endogenous amino acid and endogenous P losses, respectively. Chemical composition was not different between PTC and CC, whereas the phytase content for PTC was greater than CC (8,047 vs. 37 FTU/kg of corn, DM basis; P < 0.001). No difference was observed in the TME and true amino acid availability values between the PTC and CC in roosters. The true P utilization for PTC was greater than CC (37.92 vs. 55.85%; P < 0.001), and CC and PTC contained 0.13 and 0.19% available P (AP, DM basis; P < 0.001), respectively. There was no difference in P utilization (72.76 vs. 70.23%; P > 0.05) between roosters fed PTC and extraneous microbial phytase in equivalent FTU/kg of diets. The results of this study indicated that the chemical composition, TME, and true amino acid availability in PTC are essentially equivalent to that in CC, and the true P utilization for roosters is higher in PTC than in CC. Corn expressing phytase is as efficacious as equivalent microbial phytase when supplemented in corn-soybean diets for chickens.
authors.affiliation: College of Animal Science and Technology, China Agricultural University, Beijing, People's Republic of China.
authors.forename: C Q
authors.initials: CQ
authors.lastname: Gao
authors.forename: Q G
authors.initials: QG
authors.lastname: Ma
authors.forename: C
authors.initials: C
authors.lastname: Ji
authors.forename: X G
authors.initials: XG
authors.lastname: Luo
authors.forename: H F
authors.initials: HF
authors.lastname: Tang
authors.forename: Y M
authors.initials: YM
authors.lastname: Wei
mesh_terms: D010832:6-Phytase / Q000235:genetics / Q000378:metabolism*; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development*; D004032:Diet / Q000662:veterinary; D008297:Male; D030821:Plants, Genetically Modified; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics*
chemical_list: D010832:6-Phytase