Dietary phosphorus requirements of laying hens kept in floor pens and fed diets containing canola meal

An experiment of 46 wk duration was conducted to study the phosphorus requirements of laying hens kept in floor pens and fed diets containing different levels of canola meal (CM). The hens were given diets in which P levels were altered by adding either 10, 20 or 25% CM or an inorganic P supplement. The results obtained indicated that increasing the dietary level of P from 0.40 to 0.44, 0.48 or 0.50% by adding either CM or an inorganic P supplement had no effect on mortality, rate of production, feed conversion, body weight, blood P levels or calcification as measured by tibia or toe ash content. There was also no effect on egg quality traits as measured by egg weight, Haugh unit values, specific gravity, egg fracture force or deformation. Inclusion of CM in the diets resulted in some increase in thyroid size which was directly related to the level of CM used. The productive performance of the groups fed CM showed that the high level of P in this ingredient was well utilized by the laying hen. From the results it may be concluded that a level of 0.4% P in a laying diet, with all of the P derived from plant sources, was sufficient to meet the dietary P requirements of laying hens kept in floor pens. Key words: Phosphorus requirements, laying hens, canola meal