Abstract
ABSTRACT The aim of this study was to evaluate the effect of two types of phytases (the 1st produced from Escherichia coli and the 2nd from Aspergillus oryzae) with different dosages (300 and 900 Unit Phytase or FTU) on performance, organ biometry and bone quality of replacement pullets in the period of 8 to 17 weeks of age. A total of 288 Hy-Line White laying hens were used at 8 weeks of age. A completely randomized design was adopted in a 2 x 2 factorial scheme, totaling 4 treatments with 8 replicates of 9 birds each. Performance, biometric variables and bone characteristics were evaluated. There was no significant interaction between the factors for any of the evaluated variables. The conversion and the accumulated consumption were influenced (p<0.05) by the phytase dosages, with the highest results being observed for the consumption obtained with 300 FTU, and the best results for the feed conversion obtained with the dosage of 900 FTU. The relative weight of the liver was influenced by the treatments (p<0.05), presenting higher values with bacterial phytase and a dosage of 900 FTU. The sternum length and tibial deformity were influenced by fungal phytase (p<0.05). It is concluded that the use of 900 FTU superdosing and fungal phytase improves the performance and bone characteristics of light replacement pullets.
Highlights
Due to the great productivity of today’s poultry on the market, there is a need for research which provides relevant information on the nutrition of replacement pullet laying hens
The phytase types evaluated were bacterial phytase produced from Escherichia coli and fungal phytase produced from Aspergillus oryzae at the 300 and 900 FTU dosages, supplemented in the diet without altering the standard formulation, i.e. on top
Considering that feed conversion depends on food intake, it can be inferred that the dosage of 900 FTU, regardless of the phytase origin, was able to release more nutrients adhered to the phytate molecule, increasing its use by pullets and optimizing performance, leading to improvement in feed conversion as observed with this dosage, according to studies (Karadas et al, 2010; Cowieson et al, 2011; Beeson et al, 2017) where superdosing of phytase in the diets of birds can provide even better performance responses
Summary
Due to the great productivity of today’s poultry on the market, there is a need for research which provides relevant information on the nutrition of replacement pullet laying hens. The use of additives in monogastric diets is a common practice and often necessary in animal nutrition, with the use of exogenous enzymes among them. These enzymes are part of the group of zootechnical additives and their use in diets has grown in recent years. Such use is justified by the beneficial effects they present such as in the removal of antinutritional factors, improved digestibility and availability of phosphorus and other minerals, reducing their excretion and their deposition in the environment (Viana et al, 2009; Leite et al, 2011)
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