Effects of Nano Zinc Oxide-Enriched Diets on Bone Morphometry and Biomechanical Strength in Japanese Quails

Zinc is an essential trace element critical for numerous biological functions, including bone development, enzyme activity, and immune response. This study investigated the effects of zinc oxide (ZnO) and nano zinc oxide (NZn) supplementation on bone morphometry and biomechanical properties in Japanese quails (Coturnix coturnix japonica). A total of 118 one-day-old quails were divided into three groups: control (C), zinc oxide (Zn), and nano zinc oxide (NZn), with each group further subdivided into replicates. Diets were formulated to provide 75 mg/kg zinc, with additional zinc sources added to achieve the desired levels. Morphometric and biomechanical analyses were conducted using a 3-point bending test to evaluate tibiotarsus bone strength and structural properties. Results indicated that the NC group exhibited a significantly higher external mediolateral diameter (ExtMLD) compared to the Zn and C groups (P = 0.003), suggesting enhanced periosteal bone growth with NZn supplementation. However, no significant differences were observed in internal diameters or biomechanical parameters such as breaking force, moment of inertia, strength, stiffness, and elastic modulus among the groups (P>0.05). Sex-based comparisons revealed that female quails in the Zn and C groups had significantly higher breaking force and moment of inertia compared to males (P < 0.05). Still, no such differences were observed in the NZn group. These findings suggest that while NZn may positively influence specific morphometric parameters, its impact on biomechanical strength remains limited. The study highlights the need for further research to elucidate the mechanisms underlying zinc's effects on bone development.