Microbial and functional feed supplement to improve livestock and poultry productivity with special reference to synbiotics: A review

India is blessed with world’s largest livestock population (529.7 million) and stands on first rank in the world. Livestock sector plays an important role in national economy it contribute approximately 4% to GDP and 27% to agriculture GDP but the major problems for Indian livestock industry are gap between demand and supply of feed and fodder and diseases. To overcome these problems antibiotic growth promoters (AGP) are used worldwide in poultry and livestock industry they not only prevent some diseases but improve growth performance also. Continuous and misuses of antibiotic in livestock production resulted in development of drug resistant bacteria, drug residues in milk and body of birds and imbalance of normal micro flora. Therefore importance of alternative growth promoters such as probiotics, prebiotics and synbiotics is evident in place of antibiotic growth promoters. Probiotics are live microorganisms which when administered in adequate amount; confer health benefit on the host. Prebiotics are non-digestible but fermentable food ingredients that beneficially affect the host by selectively stimulating the growth and activity of one or limited number of bacteria. Synbiotics are the combination of probiotics and prebiotics. It is a new approach by this a food supplement will include both the live cells of beneficial bacteria and a selective substrate, bacterial cells survive and grow quickly because of selective substrate and establish their predominance.