Research Note: Utilization of Inedible Eggshells and Technical Egg White Using Extrusion Technology

An extruded eggshell product (ESP) was formulated into a laying ration of a commercial flock of 6,500 hens to provide 75% of the total calcium from 59 wk to 70 wk of age. A control treatment (22,500 laying hens) with calcium supplied by limestone was also utilized during the same time period. The formulation for ESP including 70% eggshells, 8% technical albumen (shell wringings), 5% corn, 17% soybean meal, and .15% propionic acid was blended and extruded using an extruder. Extrusion temperatures reached in excess of 121.1 C (250 F), which produced a Salmonella-free product The ESP contained 13.1% protein and 24.0% calcium. Rate of lay, feed conversion, and mortality were not adversely affected by the ESP. Also, shell thickness and breaking strength were not significantly affected by the ESP diet Extrusion technology may provide an avenue for better utilization of egg shells as well as other wastes from egg processing plants.