A Review and Evaluation of Antibiotic Alternatives in the Literature

In the coming years, there will be an increase in the use of feed-grade antibiotic alternatives in swine production due to restrictions on feed-grade antibiotics for pig performance and/or treatment. As a result, there is a need to understand effective ways to evaluate dietary antibiotic alternatives in swine production. A review of published literature was performed to determine how different antibiotic alternatives influenced growth performance. The antibiotic alternatives evaluated were: prebiotics, probiotics, resistant starch/fiber, botanicals, organic acids, lysozymes, oligosaccharides, yeast, and zinc and copper. Searches were performed on Pubmed, CAB abstracts, Sciencedirect, Agricola, and Web of Science for each category. Research papers were included if they were original research, published in a peer reviewed journal between 1990 and January 2016 and included any pig performance parameter (ADG, ADFI, G:F) or mortality in the abstract. If determined acceptable, data were extracted from each paper, including: disease challenge, n/treatment, pigs/pen, age of pig, duration of study, start bodyweight, diet components, and if performance or mortality was impacted positively, negatively, or not changed. This lead to a total of 773 papers with 1698 studies evaluated. Antibiotic alternatives improved ADG in 29.3% of studies while performance was unchanged or declined in 65.9% and 3.3% of studies, respectively, when compared to pigs fed no antibiotics. In studies that improved ADG, pigs averaged 24 days old and weighed 9.7 kg. These studies lasted 24 days on average, with 13 n/treatment and 7 pigs/pen. The most effective antibiotic alternatives were probiotics, organic acids, and zinc/copper, where an improvement in ADG was reported in 38.7%, 33.8%, and 42.6% of studies, respectively. Within each category, there was an attempt to determine factors that may have led to improved performance. About one-third of probiotic studies that improved ADG used a combination of probiotics while another third used a strain of Lactobacillus. After evaluating zinc and copper, it was determined that 3000 and 2500 ppm of zinc were used in 16.5% and 11% of studies, respectively. No other factors could be determined in other categories. In summary, antibiotic alternatives can improve performance in pigs but there may be a specific age, BW, or duration of feeding that can optimize the response. With the data obtained, we can better design and evaluate antibiotic alternative research for the swine industry.