The effects of eggshell and oyster shell supplemental as calcium sources on performance, eggshell quality and mineral excretion in laying hens

A study was conducted to determine the influence of different calcium sources in layer diets on performance, eggshell quality and mineral excretions. A total of 72 Hy-Line W36, layer birds of 25 weeks old, were distributed in 6 experimental groups randomly. In each experiment group there were 4 replicates, and in each replicates there were 3 birds. During the 12 weeks experiment period, birds were fed 6 experimental diets. Experimental diets were consisted of various calcium sources for meeting the calcium requirements. It was control (limestone), 1/3 eggshell, 1/3 oyster shell, 1/3 eggshell+1/3 oyster shell, 2/3 eggshell and 2/3 oyster shell. Dietary different sources of calcium had no significant effect on body weight change, feed conversion ratio, eggshell breaking strength, eggshell thickness, and eggshell phosphorus and magnesium contents (p > 0.05). The different sources calcium had a significantly effect on egg production, egg weight, egg mass, feed intake and eggshell weight in laying hens (p < 0.01; p < 0.05). The different calcium sources had significantly effect on eggshell calcium content, and calcium, phosphorus and magnesium excretion in hens (p < 0.01). Results of the present study observed that laying hens were not advantageous for performance by fed with eggshell and oyster shell as calcium sources.