The Relationship of Dietary Phosphorus and Sodium Aluminosilicate to the Performance of Commercial Leghorns

Abstract

To determine the influence of sodium aluminosilicate (SA) on hens (7 mo of age) fed different levels of phosphorus, 1,920 hens were fed diets containing .70, .57, .43, and .30% total phosphorus with and without the inclusion of 1.0% SA for 6 wk. Egg production, egg weight, egg specific gravity, and feed conversion were determined weekly. Birds fed .30% phosphorus with 1% SA had a much faster and greater decline in production than the hens fed .30% phosphorus without SA. For hens fed diets containing more than .43% phosphorus, egg production was not affected by level of phosphorus in the diet with or without SA. The inclusion of 1.0% SA improved egg specific gravity; also, the degree of improvement was unrelated to level of dietary phosphorus when the proportion of phosphorus was greater than .30%. Sodium aluminosilicate significantly reduced feed consumption when the level of dietary phosphorus was .30%. Hens fed diets containing .30% phosphorus with or without SA had significant reductions in egg size. However, hens fed SA at phosphorus levels above .30% had eggs that were .5 g heavier than those from hens fed the same level of phosphorus without SA.The author concluded that SA improved egg specific gravity, but had no effect on egg production when total phosphorus intake was 668 mg/hen per day or higher. Because of the strong interaction of SA by phosphorus for egg production, the level of dietary phosphorus must be considered when using SA.