Evaluation of Insect-Based Proteins as Sustainable Alternatives to Soybean Meal: Effects on Bone Biomechanics in Female Pheasants ( <i>Phasianus colchicus</i> )

Abstract This study investigated the effects of replacing soybean meal with insect-derived proteins, specifically insect meal and dried larvae, on the bone biomechanical, geometrical, and mineral properties of female pheasants ( Phasianus colchicus ). With growing interest in sustainable protein sources, insect-based alternatives are being explored due to their high protein content, favorable amino acid profiles, and reduced environmental impact. However, their effects on skeletal health remain insufficiently characterized. Fifty female pheasants were randomly assigned to one control group (soybean meal-based diet) and two experimental groups, each further divided into subgroups receiving 50% or 100% replacement of soybean meal with insect meal or dried larvae. Birds were housed under standardized conditions, and tibia and femur were analyzed for bone mineral content (BMC), bone mineral density (BMD), geometric parameters, and mechanical properties using densitometry and three-point bending tests. The control group showed higher BMC of tibia bone compared to experimental groups, indicating potential differences in mineral retention. Geometric traits such as cross-sectional area and cortical index were also affected, with reduced cortical thickness in some insect-fed birds. Mechanical testing revealed lower yield force and stiffness of tibia in experimental groups, suggesting alterations in bone matrix quality. However, BMD remained stable across groups, implying that mineral concentration was preserved despite reduced total content. These results suggest that insect-based proteins are viable soybean meal alternatives, with partial replacement maintaining bone quality more effectively than full substitution. Further research is needed to optimize dietary formulations for skeletal health while advancing sustainability in poultry nutrition.