Nutrient retention and carcass accretion responses of broilers fed high levels of phytase in diets adequate or deficient in non-phytate phosphorus
A total of 344 Ross 308 broilers were used to study the effect of high levels of phytase supplemented to diets adequate or deficient in non-phytate P (nPP). Eight birds at day-old formed an initial slaughter group and the remaining 336 birds were allocated to 6 treatments (3×2 factorial) in a randomised complete block design, with 3 levels of phytase (0, 1500 and 3000 FTU/kg) and 2 levels of nPP (NC, 0.30% and PC, 0.45%). Adding 1500 FTU/kg phytase increased (P ≤ 0.05) total tract retention (TRR) to a greater extent in the NC than the PC diet whereas supplementation of 3000 FTU/kg phytase only increased (P < 0.05) TTR of Ca and P in the NC compared with the PC diet. Carcass energy retention, energy retained as protein and efficiency of energy retention were greater (P < 0.05) in PC+1500 FTU than NC+1500 FTU. Phytase had no effect on energy retained as fat but heat production was greater (P < 0.01) in birds fed NC+1500 FTU compared with PC+1500 FTU. Phytase had no effect on proportion of energy used for maintenance in the PC diets but increasing phytase from 1500 to 3000 FTU/kg decreased (P < 0.05) proportion of energy use for maintenance in the NC diets. It is concluded from the current study that although phytase supplementation improved total tract nutrient utilisation in NC, the efficiency of utilisation of nutrients for whole body energy accretion was greater in the PC than NC diets.
Other Titles/Title of Conference
XIVth European Poultry Conference, Stavanger, Norway
The World's Poultry Science Association