Short-term exposure of laying hens to high dietary sodium chloride levels

Four replicate pens, each containing five individually caged hens received a corn-soy basal diet to which .4, 1, 2, 4, or 6% NaCl was added during two 21-day experiments. An additional bilevel treatment, approximating a reported commercial feed production problem, consisted of 6% NaCl for 7 days followed by .4% NaCl for the remaining 2 weeks. Egg production was significantly reduced by 4 and 6% NaCl in Experiment 1 and by 2, 4, and 6% NaCl in Experiment 2. The switchback treatment (6-.4% NaCl) did not statistically alter overall egg production in either experiment. Daily water consumption increased significantly when more than 1% NaCl was added, and subsequently with each feed addition. When 6% NaCl was fed for 7 days feed intake was quickly suppressed; this caused a rapid increase in water intake. Water intake returned to normal levels before the end of the second week. Daily feed intake was significantly reduced by a continuous feeding of 4% or more NaCl. A 1-week exposure to the 6% treatment suppressed feed intake quickly but intake recovered within one week. In both experiments, only the continuous 6% NaCl feeding regime of Experiment 1 resulted in a significant loss of body weight or a significant reduction of overall egg weight averages. Mortality was not a factor in either experiment. These data indicate that at least 2% NaCl in feed was required before any significant effects were noted, and that laying hens recovered from a 1-week exposure to 6% NaCl in feed within the following week.