Phytases are used in animal nutrition to improve the utilization of dietary P and reduce P excretion, saving in diet formulation costs while reducing the environmental impact. Buttiauxella sp. phytases have been reported to have higher efficacy in improving total tract P digestion and to provide successful phosphorous release at dose rates above 500 FTU/kg. The objective of the present study was to test if a novel phytase from Buttiauxella sp. could replace all added inorganic phosphate in a diet with reduced Ca and metabolizable energy (ME) fed to commercial pigs from 12 kg body weight (BW) until slaughter, whilst maintaining performance and carcass quality parameters. A total of 1116 crossbreed piglets were allocated to 4 dietary treatments: a positive control (PC) based on a corn, soybean meal, wheat middling and bakery meal; a negative control (NC) excluding inorganic phosphate and with reduced Ca (−0.13%) and ME (−0.15 MJ/kg); and two NC diets supplemented with Buttiauxella phytase at 500 or 1000 FTU/kg feed. Diets were fed ad libitum in mash form in 5 phases: starter (12 to 25 kg BW), grower 1 (25 to 50 kg BW), grower 2 (50 to 75 kg BW), and finisher 1 (75 to 100 kg BW) and 2 (100 kg BW to slaughter).
From the starter phase until the end of the grower period, pigs fed supplemented diets with phytase at 1000 FTU/kg achieved similar levels of ADG, ADFI and G:F as the PC, and an improved ADFI and ADG compared with 500 FTU/kg phytase. For the entire growth period to slaughter no significant differences were observed between both phytase inclusion levels and the PC fed group, although pigs receiving phytase at 1000 FTU/kg feed tended to have greater percentage yield compared with 500 FTU/kg. Pigs fed the NC diet had lower ADFI, ADG and G:F compared with those receiving the PC. No differences were observed for BW at slaughter, carcass weight and percentage of lean carcass between the PC diet and the 2 phytase treatments.
The application of Buttiauxella phytase could therefore replace all inorganic P and replace 0.13% Ca and 0.15 MJ/kg ME in the diet, while maintaining growth performance and carcass characteristics in commercial pigs as well as reducing the feed cost.
Dersjant-Li, Y., Plumstead, .P, Awati, A. and J. Remus. 2018. Productive performance of commercial growing and finishing pigs supplemented with a Buttiauxella phytase as a total replacement of inorganic phosphate. Animal Nutrition. In press (xx) 1-7. Open acces. https://doi.org/10.1016/j.aninu.2018.02.002