Eggshell as an alternative calcium source to conventional sources in broiler nutrition

This study compared the effects of different calcium (Ca) sources, including limestone (LS), cockle shell (CS), oyster shell (OS), and eggshell (ES) powder, on the growth performance, meat quality, organ and intestinal characteristics, blood parameters, and tibial characteristics of broilers. A total of 800 one-day-old male Ross 308 chicks were randomly assigned to four dietary treatments (LS, CS, OS, ES), with five replicate pens per treatment and 40 chicks per pen for a duration of 4 weeks. ES supplementation exhibited no significant differences in growth performance, organ attributes, and intestinal characteristics. ES treatment slightly reduced thigh meat redness (a*) (p < 0.01). The spleen weight showed increasing trends in the LS and ES groups (p = 0.06). Additionally, the duodenal length in the OS group was shorter than that in the LS group, whereas the caecal length in the CS group was shorter than that in the LS and ES groups (p < 0.05). Blood creatinine levels were lower in the CS, OS, and ES groups than those in the LS group (p < 0.05). ES supplementation tended to increase tibial bone mineral density (p = 0.067). These findings suggest that ES supplementation has no adverse effects and may provide benefit bone and blood health. As a safe and viable alternative calcium source to limestone (LS) in broiler diets, eggshell (ES) holds potential to enhance environmental sustainability through the repurposing of waste materials.