Necrotic enteritis (NE) is an enterotoxaemia of poultry with a significant economic effect on poultry production. Currently, antibiotics effectively prevent NE, but there is a global push for reduced reliance on the use of in-feed antibiotics (Castanon, 2007). Preventative treatments focus on the predisposing factors that instigate the disease. One such factor is meat and bone meal (MBM). The ingestible proteins in MBM (Kim, et al., 2012) cause production of toxic metabolites via proliferation of putrefying bacteria, such as highly proteolytic C. perfringens (Sharma, et al., 2017). Supplementing broiler diets with a 'superdose' of phytase has previously been shown to improve performance in NE challenged birds. The aim of this study was to investigate the effects of phytase in NE challenged birds fed MBM based diets, on gut permeability, nutrient digestibility and caecal microflora

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.

Traditionally, Zn, Cu and Mn have been added to poultry diets in the form of inorganic salts, such as sulphate, to meet requirements and prevent deficiencies. The sulphate sources of trace minerals have low bioavailability, are highly water soluble and reactive in the feed and digestive tract (Ma et al., 2011). Hydroxychloride minerals (HyC) are a class of naturally occurring minerals with fully defined crystalline structure, where the crystal is held together by a series of covalent bonds between the metal ion, multiple hydroxyl groups and the chloride ions. Compared to inorganic salts, HyC minerals have been found to be less water soluble, more bioavailable and exhibit less oxidant promoting activity in the feed (Perez et al., 2017).