Evaluating a novel consensus bacterial 6-phytase variant on growth performance of broilers fed U.S. commercial diets deficient in nutrients and energy through 63 days of age.
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An experiment was conducted to evaluate the efficacy of a novel consensus bacterial 6-phytase variant expressed in Trichoderma reesei (PhyG) in broilers fed corn-soybean meal-based diets with application of dose-specific full nutrient and energy matrix values. Ross 708, straight-run broilers (n = 2,016) were assigned to one of 7 dietary treatments, with 12 replicate pens/diet and 24 birds/pen. Diets were a nutrient adequate control (PC), nutrient reduced negative controls 1, 2, and 3 (NC1, NC2, and NC3) with reductions in available phosphorus (avP) by 0.15%, 0.18%, and 0.19%, calcium (Ca) by 0.17%, 0.20%, and 0.21%, dig amino acids (AA) by 0.02%-0.05%, sodium (Na) by 0.03%-0.05%, and metabolizable energy (ME) by 62.8, 68.8, and 69.5 kcal/kg, respectively. Other diets were the NC1, NC2, and NC3 respectively supplemented with 500 (PhyG500), 1,000 (PhyG1000), and 2,000 (PhyG2000) FTU/kg. Over the 63-day feeding period, decreasing nutrient specifications lowered body weights (P < 0.05) in broilers from 4,518 g in PC to 4,256 g and 4,191 g and increased body weight-corrected feed conversion ratio (FCR, P < 0.05) from 1.92 in PC to 2.06 and 2.08 in the NC2 and NC3, respectively. Compared with PC, PhyG maintained (P > 0.05) BW in broilers fed PhyG500 (4,474 g), PhyG1000 (4,417 g), and PhyG2000 (4,449 g). Moreover, PhyG at all dose-levels maintained (P > 0.05) overall FCR vs. PC. The NC1, NC2, and NC3 diets decreased (P < 0.05) tibia ash vs. PC, and each PhyG500, PhyG1000, and PhyG2000 completely restored tibia ash to the similar levels (P > 0.05) as the PC. Carcass yield was decreased (P < 0.05) by NC1 (80.63%), NC2 (80.51%), and NC3 (80.31%) vs. PC (81.96%) with complete alleviation by PhyG500 (82.11%), PhyG1000 (81.80%), and PhyG2000 (81.54%). In conclusion, the novel consensus phytase variant completely compensated for the reduction in dietary avP, Ca, dig AA, and ME at each dose-level and maintained growth performance, bone quality, carcass characteristics, and nutrient digestibility in a typical corn-soybean mean based diet fed to broilers through 63 days of age.
