Inability to Demonstrate an Effect of Eggshell #49 on Shell Quality in Older Laying Hens

Short term studies were conducted with older laying hens to evaluate the efficacy of Eggshell #49 (Alltech, Inc., Nicholasville, KY) in improving shell quality. The product is a combination of several trace mineral proteinates, most prominently manganese and zinc. Both these trace minerals are essential for proper eggshell formation. Results of these studies failed to show a positive effect of the test product on eggshell quality, as measured by specific gravity. It should be noted, however, that levels of manganese and zinc in the basal diet contained ample margins of safety. Whether the test product would have given positive results with marginal levels of inorganic trace mineral supplementation was not addressed in these studies.