Response of Commercial Leghorns to Sodium Aluminosilicate When Fed Different Levels and Sources of Available Phosphorus

Abstract

Two experiments were conducted to elucidate possible explanations for the adverse interaction of sodium aluminosilicate (ZA) and low phosphorus on egg production. In Experiment 1, hens were fed available phosphorus at two levels (.40 and .31%) and from three sources (dicalcium phosphate, defluorinated phosphate, and meat and bone meal). Two levels (0 and .75%) of ZA were concomitantly fed with these treatments. In Experiment 2, hens were fed two levels (.30 and .20%) and two sources (dicalcium phosphate and defluorinated phosphate) of phosphorus with and without ZA (0 and .75%). In both experiments, egg production, egg specific gravity, feed consumption, and egg weight were measured. In Experiment 2, plasma sodium, potassium, chloride, total and free calcium, and phosphorus were also monitored. Results of both Experiments indicated that ZA significantly increased egg specific gravity; whereas, phosphorus level and source had no effect on egg specific gravity. Egg production was influenced by ZA level, phosphorus source, and phosphorus level with significant phosphorus source by phosphorus level interactions. In Experiment 1, ZA reduced egg production at the higher phosphorus level when dicalcium phosphate or defluorinated phosphate was used but not at the lower phosphorus level. Egg production was not influenced by ZA when meat and bone meal was the source of phosphorus. In Experiment 2, ZA reduced egg production more at the lowest level of phosphorus and more when the phosphorus source was defluorinated phosphate than when it was dicalcium phosphate but the interaction was not significant Sodium aluminosilicate had no influence on egg weight, but it did reduce feed consumption. Plasma electrolytes were influenced by phosphorus source, phosphorus level, and ZA, and there were interactions among the main effects. The effects on plasma constituents were greater when measurements were made at 1 wk versus 6 wk on the experimental diets.