The use of antibiotics in poultry growth and disease control has led to antibiotics resistant problem in human beings, which is a big concern among consumers. With the necessity for judicious use of antibiotics in poultry production, alternative strategies to improve disease resistance in poultry production are necessary. The research is more inclined towards using the natural products available to grow healthier and antibiotic free meat animals. In the context of exploring natural and sustainable resource of alternative to antibiotics, the biochemical milieu of eggshell membranes (ESM) were analyzed by using mass spectrometry techniques including matrix assisted laser desorption ionization and liquid chromatography coupled with tandem mass spectrometry (MALDI-TOF-MS and LC-MS/MS). We found more than 300 proteins and the abundant among them are lysozyme, ovotransferrin, ovocleidin, clusterin, ovokeratin ovodefensin and many more. These proteins are not only antimicrobial in nature, but also many, play a vital role in metabolic and developmental processes. A series of experimental trails were done in which chickens by feeding ESM supplemented diet. Our initial experiments showed that feeding 0.5% levels of eggshell membrane not only improved the body weight of chickens, but also modulated immunoglobulin parameters and stress levels. Further experiments were done to see the effect of ESM under endotoxin challenged conditions in which 5 week old chickens fed with ESM supplemented or control diet were challenged with Salmonella lipopolysaccharide. Our results showed significant difference in body weight loss, pro and anti-inflammatory genes, and serum corticosterone levels in control versus ESM fed chickens. ESM supplemented diet not only helped to restore the body weight loss due to LPS injection but it also helped to provides better tolerance to endotoxin challenges as indicated by splenic cytokine profiles of the chickens. In view of the need for alternatives to antibiotics in meat animal production, exploring the potential of egg byproducts as nutritional modulator of immunity during post hatch period appears logical
