Effect of reducing dietary anions (phosphate and chloride) on production characteristics of layers

The purpose of this experiment was to determine the response of a single strain of high producing Single Comb White Leghorn-type hens to diets containing phosphorus at levels of 0.4 and 0.8 percent each with sodium being fed at a level of 0.25 percent in all the diets but with chlorine at levels of 0.36 or 0.16 percent.

The higher level of chlorine was attained through additions of salt (NaCl) to the basal diet. Furthermore, two low chloride sodium sources were added to the basal diet to reduce the dietary chlorides to the 0.16 percent level. Sodium bicarbonate served as one of these low chloride sources with a mixture of various sodium compounds serving as the second. This latter source was provided by Syntex Agribusiness, Inc. and was composed of a mixture of sodium bicarbonate, sodium sulfate, sodium propionate and 1.00 percent inert ingredients to contain 27.0 percent sodium.

Two trials were conducted, the first of 16 weeks duration and the second of 14 weeks duration. Results were subjected to analysis of variance. There appeared to be differences in response to dietary treatments as measured by shell quality, egg weight and body weight gain, but, these differences proved to be statistically nonsignificant. Neither were significant differences found between dietary phosphorus or low chloride sodium sources for egg production, feed consumption, percent mortality, or initial body weight.

Consistent trends were found between shell quality and dietary levels of both phosphorus and low chloride sodium sources. Feeding 0.4 percent phosphorus as compared to 0.8 percent resulted consistently in shells with higher specific gravity scores. Feeding the sodium source mixture to hens resulted in higher quality shells than were obtained by feeding either salt or sodium bicarbonate. Also, the hens fed the sodium source mixture in combination with 0.4 percent phosphorus produced eggs with specific gravity scores higher than those produced with any of the other diets.