To determine whether buckwheat phytase can be used as an alternative phytase source, growth performance, bone quality and P retention were measured in broilers given non-phytate P-deficient diets. Non-germinated (BU) and germinated (GBU) buckwheat were used: they were ground and sieved to remove hulls before use. A total of 120 male broiler chicks (8 d of age) were divided into 8 groups (15 birds each) and given one of the following 8 diets until 42 d of age: positive control (PC) diet satisfying recommended level of all nutrients, negative control (NC) diet formulated to contain 0.16% lower non-phytate P than PC diet, and six other diets, formulated by replacing maize in NC diet with BU or GBU at 10%, 15% and 20% concentrations. Starter diets contained 23.5% crude protein (CP) and 3,200 kcal of ME/kg, and were used for 8-21 d of age. Then, grower diets with 20.5% CP and 3,250 kcal of ME/kg, and were provided for 22-42 d of age. Compared with the PC group, NC group showed impaired growth performance (BW gain, FI, and FCR), and bone quality (dry weight, breaking strength and contents of ash and P in tibia). However, in most cases, these impairments were ameliorated dose-dependently by the addition of BU and GBU in diets, and the restoration magnitude was greater in GBU than in BU treatment. Total P excretion decreased in NC group and further decreased dose-dependently with increasing levels of BU and GBU. Except for the values in PC group, total P retention increased as the total P excretion decreased. In conclusion, dietary BU and GBU restored the growth performance and bone quality impaired by the P deficiency, and improved P retention in broilers, which suggested that buckwheat, especially when germinated, can be used as an alternative phytase source in broiler diets.
Keywords: bone quality; broilers; buckwheat; growth performance; phosphorus retention.
2018 by Japan Poultry Science Association.