Repurposing Chicken Eggshell Waste as Nutraceuticals: Improvement of Biomarkers in Protein-Malnourished Rats

Background Malnutrition, specifically protein-energy malnutrition, significantly impairs growth and overall health, marked by deficiencies in serum protein, haemoglobin, and insulin-like growth factor-1 (IGF-1). Chicken eggshell (CE) powder, a rich source of bioactive nutrients, remains underutilized despite its high mineral and protein content. Objective To evaluate the efficacy of chicken eggshell powder supplementation on biomarkers associated with nutritional status—serum protein, haemoglobin, IGF-1, haematocrit, erythrocytes, and retinol-binding protein (RBP) in malnourished rats fed a protein-restricted diet. Methods Thirty male rats (Rattus norvegicus), initially malnourished through a low-protein diet (4% w/w protein BW) for four weeks, were divided into three groups: a control group (normal protein diet, 23% w/w protein), a low-dose CE group (100 mg/kg BW), and a high-dose CE group (200 mg/kg BW). Supplementation lasted another four weeks, after which blood biomarkers and body weight changes were analysed using ELISA and statistical analyses (ANOVA and paired t-tests). Results Administration of CE powder significantly increased haemoglobin and IGF-1 levels, particularly at the higher dosage (200 mg/kg BW; p<0.0001). Both doses (100 mg/kg BW and 200 mg/kg BW) similarly enhanced haematocrit and erythrocyte levels compared to the control group (p=0.0513). RBP was significantly elevated with the higher dose compared to the lower dose (p<0.0001). Serum protein levels increased dose-dependently, although without statistical significance between dosages. Body weight increased across all groups, with significant weight gain in the high-dose group (p=0.048). Conclusions Chicken eggshell powder supplementation notably improves critical biomarkers related to malnutrition, especially at a dosage of 200 mg/kg BW, indicating its potential as a cost-effective and sustainable nutraceutical strategy for addressing malnutrition and protein deficiencies.