fa عمومى General پژوهشي Research <span style="font-size:11pt"><span style="line-height:85%"><span style="font-family:Calibri,sans-serif"><span lang="EN" style="font-size:12.0pt"><span style="line-height:85%"><span new="" roman="" style="font-family:" times=""><span style="color:black">The livestock, poultry, and aquaculture industries are essential for global food security and animal protein production. However, infectious diseases continue to cause substantial economic losses through increased mortality, impaired growth performance, reduced productivity, and elevated treatment costs. In response to growing concerns regarding antibiotic resistance and the excessive use of antimicrobial agents, immunostimulants have emerged as promising alternatives for disease prevention and health management. Among these compounds, egg yolk immunoglobulin (IgY) has attracted considerable attention due to its high specificity, safety, cost-effective large-scale production, and broad antimicrobial potential. This review summarizes the current knowledge regarding the use of immunostimulants in livestock, poultry, and aquaculture, with particular emphasis on the biological properties, mechanisms of action, and practical applications of IgY. In addition, the potential role of IgY in improving animal health, enhancing immune responses, reducing mortality, and increasing production efficiency is discussed. The available evidence suggests that IgY may serve as an effective alternative or complementary strategy to antibiotics in modern animal production systems. Its application could contribute to improved sustainability, reduced antimicrobial dependence, and enhanced economic performance across livestock, poultry, and aquaculture industries.</span></span></span></span></span></span></span> &nbsp; IgY, immunostimulants, livestock, poultry, aquaculture, antibiotic alternatives, animal health. 119 127 http://injvr.com/browse.php?a_code=A-10-1-34&slc_lang=fa&sid=1 A. Kargar-Kheirabad 10031947532846001598 10031947532846001598 No Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; R&D Department, Arghavan Teb Kavian Knowledge-Based Company, Karaj, Iran. S.M.J. Zorriehzahra 10031947532846001599 10031947532846001599 Yes Department of Aquatic Animal Health and Diseases, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran. M. Ghasemi 10031947532846001600 10031947532846001600 No Inland Waters Aquaculture Research Center, Iranian Fisheries Science Research Institute (IFSRI), AREEO, Bandar Anzali, Iran. S. Hossein Garkani 10031947532846001601 10031947532846001601 No Department of Medicinal Chemistry, School of Medicinal Chemistry, Islamic Azad University, Tehran, Iran. S.M. Mousavi Shahtouri 10031947532846001602 10031947532846001602 No Department of Animal Sciences, R&D Department, Arghavan Teb Kavian Knowledge-Based Company, Karaj, Iran. K. Radkhah 10031947532846001603 10031947532846001603 No Department of Aquatic Animal Health and Diseases, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran. H. Rafiee 10031947532846001604 10031947532846001604 No Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran. S. Yousefian Jezi 10031947532846001605 10031947532846001605 No Department of Nano-Biotechnology and Bio-inspiration, Faculty of Bio-science Engineering, College of Science, University of Tehran, Tehran, Iran. M.R. Abedini 10031947532846001606 10031947532846001606 No Assistant Professor, Islamic Azad University, Tehran, Iran.