Effect of Supplemental Aluminum on the Value of Fertilizer Phosphates in Turkey Diets ,

Two experiments were conducted with Large White turkeys to evaluate high-fluorine, fertilizer phosphates, diammonium phosphate (DAP) and concentrated superphosphate (CSP) along with partially defluorinated phosphate (PDP) and monocalcium phosphate (MCP) as sources of supplemental phosphorus. Aluminum as an alleviator of fluorine toxicity in starting and growing-finishing turkeys was studied. Fertilizer phosphates, PDP and MCP were each added to furnish all the dietary supplemental phosphorus. Aluminum sulphate was added to provide 0, 295 or 590 p.p.m. of Al in the first experiment and about a 1:1 A1:F ratio in the second experiment. CSP and DAP were somewhat toxic, significantly (P < 0.05) depressing body weight and feed efficiency when fed to supply all supplemental phosphorus from day-old to 20 weeks, but CSP was not toxic for short periods, day-old to four weeks. Only CSP and DAP significantly (P < 0.05) increased bone strength, bone ash and fluorine level of bone ash. Fluorine content of muscle was significantly (P < 0.05) increased by DAP. Aluminum partially eliminated the toxic effect of DAP and CSP, but was not effective in preventing all symptoms of fluorine toxicity produced by the fertilizer phosphates. It was concluded from results of this study that PDP was an excellent phosphorus source for young turkeys. However, DAP and CSP should be added to furnish only a portion of the supplemental phosphorus along with feed grade phosphates.