Two studies evaluated the effects of a novel consensus bacterial 6-phytase variant on the growth performance of broilers fed corn/soybean diets and deficient in nutrients and energy

Two experiments were conducted to evaluate the effects of a novel consensus bacterial 6-phytase variant (PhyG) on performance of broilers fed US type diets with reduced nutrients and energy. Each experiment utilized a completely randomized block design where four treatments were tested with 10 replicate groups, each treatment totaling 270 day-of-hatch male Ross 308 broilers. The diets were: 1), a nutrient-adequate control (PC) and 2), a nutrient and energy-reduced negative control (NC): PC minus 0.19 % avP, 0.23 % Ca, 0.045 % Na, up to 0.05 % unit dig AA and 37 kcal/kg ME and 3), NC with PhyG supplemented at 1,500 FTU/kg (PhyG1500) 4), PC minus 0.164 % avP, 0.201 % Ca, 0.037 % Na, up to 0.035 %-unit dig. AA and 29 kcal/kg ME plus the PhyG at 750 FTU/kg (PhyG750). Xylanase was included in all diets at 750 XU/kg with 25 kcal/kg of ME matrix applied. Experiment 1 diets (wholly vegetable) were based on corn-soybean meal with <2 % DDGs. Experiment 2 diets (conventional) were based on corn-soybean meal with <3 % DDGS and <4 % meat and bone meal. Diets were pelleted and fed ad libitum over four phases: starter (1–10d), grower (11–21d), finisher 1 (22–35d), and finisher 2 (36–42d). In both experiments, compared with PC, birds fed the nutrient and energy reduced NC exhibited reduced 42d BW and increased overall 1–42d FCR (P < 0.05). During all phases, in both experiments, PhyG at each dose-level produced growth performance measures that were by phase and cumulatively equivalent to PC. PhyG at 1500 FTU improved accumulative FCR (1–21d, 1–35d and 1–42d) in experiment 1, and 1–21d FCR in experiment 2 compared to PC. Similarly, PhyG750 and PhyG1500 increased (P < 0.05) tibia ash and carcass yield vs. NC to similar levels as PC. For all measures, response values were numerically highest with 1500 FTU/kg. In conclusion, the novel consensus phytase variant completely compensated for the reduction in avP, Ca, Na, dig AA, and ME respectively at each dose-level and maintained growth performance, carcass characteristics, and bone quality of broilers fed wholly vegetable or conventional US type commercial diets through 42 days of age, leading to reduced feed cost and production benefit.