<b>Sustainable synthesis of hydroxyapatite from poultry waste for veterinary applications: A calcination approach</b>

Background: Chicken eggshells and bone waste are waste materials rich in calcium (Ca) and phosphorus (P), and they are often discarded despite their potential value. These materials are promising precursors for hydroxyapatite (HA), a biocompatible material structurally similar to natural bone that is widely used in biomedical applications. Aim: To evaluate the Ca and P contents of broiler chicken eggshells and bone waste and to synthesize HA from these waste materials. The results highlight the potential of broiler chicken bones as a sustainable source of HA, particularly for veterinary bone graft applications. Methods: Eggshell and chicken bone waste samples were collected from restaurants. The samples were washed, cleaned, dried, and heated at 800 °C to produce calcite. The resulting calcite suspension was synthesized by heating it at 70 °C and gradually mixing it with an ammonium phosphate ((NH4)2HPO4) suspension over 30 min. During the mixing process, the solution pH was maintained above 9. The HA synthesized from eggshells was then analyzed using titration to determine Ca content and spectrophotometry to measure P content. Results: The analysis revealed that eggshells contained 15.986 ± 0.188% Ca and 13.794 ± 0.176% P, whereas chicken bones had higher Ca and P levels, with 18.9 ± 0.386% Ca and 13.906 ± 0.320% P. The average Ca:P ratio was 1:1.158 for eggshells and 1:1.359 for chicken bones. Conclusion: This study demonstrates the feasibility of converting poultry industry waste into valuable biomaterials to promote sustainable practices. The higher Ca and P levels observed in chicken bones than in eggshells may offer superior potential for treating pet fractures.