Eggshell as a calcium source replacing limestone meal in mink (Neovison vison) diets

An experiment was carried out to study the suitability of ground eggshell as a calcium (Ca) source in mink (Neovison vison) diets replacing limestone meal. In the study two treatment groups of six multiparous lactating females were used. Animals were fed diets containing either eggshell or limestone from May 9 to weaning on June 15 (lactation period) and continued with 10 male kits from each respective group from June 16 until termination on November 28 (growing period). Moist diets containing mainly slaughterhouse by-products, fish, maize starch and soybean protein concentrate were used. The added eggshell or limestone represented about 60% of total Ca contents in the diets for lactating females and 27 (limestone diet) or 26% (eggshell diet) in the kit growing period. Growth performance, Ca and P digestibility, and femur development were studied. The apparent total tract digestibility (ATTD) of Ca and P of each diet was measured in six male kits. There were no significant differences between diets with added eggshell or limestone meal in ATTD of Ca and P, but eggshell tended (P < 0.06) to promote higher Ca digestibility than limestone. Replacing limestone with eggshell in the diets for growing kits resulted in significantly (P < 0.05) higher feed intake and weight gain, increased body length, and lowered feed efficiency ratio. Dietary eggshell significantly (P < 0.05) increased length and weight of femur in mink kits, whereas femur thickness and contents of ash, Ca and P were unaffected. So, it can be concluded that eggshell can replace limestone as a suitable Ca source in mink diets.