Xin Zhao
College of Animal Science and Technology, Northwest A&F University

Routine use of antibiotics at sub-therapeutic levels in animal feed is increasingly being questioned due to appearance of resistant strains of bacteria. Antibiotics as growth promoters have been banned in many countries. Current proposals to curtail antibiotics in animal feed in other countries have kindled the interest of using alternatives such as probiotics, prebiotics, organic acids, enzymes and plant extracts to improve the growth and health of livestock. Many experiments have been carried out to study the effects of probiotics, with inconsistent results. Main reasons for the inconsistence are production environment, sources of probiotics, influence of feed processing and storage of probiotic products. The main target of probiotics is the digestive microflora and its functions as its stability is essential for the health and nutrition of the host. Our probiotic research will be focused on development of a careful selection process to choose microorganisms for production of probiotics. Quality control will be performed both during the production process and on the final product. Finally, it may be necessary to combine probiotics with other alternative feed ingredients or with a change in husbandry practices to achieve the best effects.