Effect of sodium aluminosilicate, oyster shell, and their combinations on acid-base balance and eggshell quality

Three experiments were conducted to determine the effect of sodium aluminosilicate (SAS), oyster shell (OS), and their combinations on production performance, eggshell quality, and acid-base balance. Experiments 1 and 2 were conducted during summer and Experiment 3 in winter. In Experiment 1, the effect of two levels of SAS (0 and .75%) and two levels of OS (0 and 50% substitution for pulverized limestone) was studied. In Experiment 2, the effect of SAS (.75%) with or without Na adjustment was investigated. When Na was adjusted, various sources of chloride were used to maintain an adequate level of this mineral. Calcium and available P were maintained at a constant 3.5 and .4%, respectively in Experiments 1 and 2. In Experiment 3, the levels of SAS and OS were similar to those of Experiment 1, but dietary Ca was either 2.8 or 3.5%. Egg production performance was not influenced by dietary treatments in Experiments 1 and 2 (P greater than .05). Egg production, but not egg mass, was reduced due to SAS in Experiment 3 (P less than .05). Dropping moisture increased when SAS was used in the diets with or without Na correction. Shell quality increased (P less than .05) due to SAS in the summer (Experiments 1 and 2) but not in the winter (Experiment 3). The shell quality response due to SAS was independent of Na correction or the source of dietary chloride. The OS increased shell quality in both summer and winter (P less than .05). Combinations of SAS and OS did not have an additive effect on shell quality (P greater than .05). Blood acid-base balance, plasma Ca and P, bone ash, bone Ca, and Ca retention were not influenced by dietary treatments. The results suggest that elevated environmental temperatures may be required in order for SAS to show its optimum effect on shell quality.