Effect of Meat and Bone Meal, Phytase and Antibiotics on the Ash Content and Breaking Strength of Broiler Femurs, Tibia and Toe

Abstract

Worldwide pressure to remove in-feed antibiotics from the poultry industry has resulted in heightened presence of the disease necrotic enteritis (NE) in broilers. Meat and bone meal (MBM) is readily used in broiler diets as a good source of protein, calcium and phosphorus, but it is also a predisposing factor for NE. A potential alternative to both antibiotics and MBM is the enzyme phytase, due to its ability to enhance nutrient digestion, particularly calcium and phosphorus. Enhancing mineral utilization and limiting nutrient availability for feeding pathogenic bacteria in the gut. The aim of this study was to use analysis of bone formation as a tool to assess the effects of phytase, MBM and antibiotics in broilers challenged with NE. Tibia and femur breaking strength and ash content and toe ash content was measured in NE challenged Ross 308 broilers (n=96) fed diets either with or without MBM, with or without antibiotic and either 500 or 1500 FTU/kg phytase, on d42 post-hatch. Results showed that MBM inclusion increased the tibia and femur ash content (P = 0.003 and P = 0.002, respectively) and breaking strength (P = 0.001). Toe ash content was highest in birds fed the low phytase level with antibiotic, as illustrated by a phytase x antibiotic interaction (P=0.031). Antibiotic had very little effect on bone ash content or strength. In conclusion, toe ash analysis suggests phytase has potential as a replacement for MBM, but further investigation is warranted into its ability to improve tibia and femur formation.