Antibiotic alternatives in livestock feeding

Since the mid-20th century, feed antibiotics have been extensively utilized due to their substantial benefits in animal husbandry. However, while feed antibiotics brings great benefits, the serious harm they produce has also attracted people's attention, mainly in inducing bacterial resistance, threatening animal and human health, leading to drug residues, and aggravating environmental pollution. Consequently, numerous countries have proposed legislation to ban feed antibiotics, which has prompted a substantial body of research focusing on green, safe, and sustainable alternatives to feed antibiotics. The present major antibiotic alternatives for feeding include enzymes, acidifiers, antimicrobial peptides (AMPs), phages, nanoparticles, microecological agents, and plant extracts. These alternatives have been shown to reduce antibiotic resistance, improve feed quality, enhance animal health, promote sustainable development of animal husbandry, and significantly increase economic benefits. This paper will focus on the mechanism and mode of action of various feed antibiotic alternatives, their application and effects in animal feed, discuss the challenges and solutions in their practical application, and look forward to their future development prospects to promote the healthy and sustainable development of animal husbandry.