Phytochemicals as antibiotic alternatives: mechanism of action of enhanced anti-oxidant and growth promoting effect of dietary phytochemicals

Authors: Lillehoj, Hyun; PARK, INKYUNG - US Department Of Agriculture (USDA)

Submitted to: American Dairy Science Association (ADSA) - American Society of Animal Science (ASAS) Joint Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/20/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: For the agricultural industry, there are heightened concerns globally on emerging drug-resistant bugs and the lack of new antibiotics for treating animal diseases. Therefore, there is an increasing need to find novel antibiotic alternative-strategies to replace antibiotics for food-producing animals. In recent years, a wide variety of herbs and spices have been used in animal agriculture for their potential application as antibiotic growth promoter (AGP) alternatives. In addition to herbs and spices, various essential oils have been used individually or as blends to improve animal health and performance. I will highlight several examples of successful agricultural use of various phytochemicals as antibiotic alternatives to reduce AGPs in this talk. One commercial blend of phytonutrients (containing carvacrol, cinnamaldehyde and Capsicum oleoresin) which enhances innate immunity and reduces negative effects of enteric pathogens such as Eimeria and Clostridium, was approved in the EU as the first botanical feed additive for improving performance in broilers and livestock. Several trials performed with this commercial blend have demonstrated consistent improvement in growth and feed efficiency. A meta-analysis of 13 broiler studies involving the use of this commercial blend showed that its inclusion in diets increased body weight gain and decreased feed conversion ratio and mortality. More recently, we have studied M. officinalis (Magnolia) tree bark (MBE) which has been widely used in traditional Asian medicine. In this study, the effect of dietary MBE was investigated in post-hatch baby chickens in experimental avian necrotic enteritis. Feed intake, body weight gain, and final body weight were increased between days 1 and 35 of age in uninfected and E. maxima/C. perfringens co-infected chickens fed with MBE diets compared with controls. In general, transcripts for antioxidant enzymes were increased in chickens fed with MBE groups compared with unsupplemented controls, and significant interactions between dietary supplementation and co-infection were observed for all antioxidant enzyme transcript levels. To better understand underlying molecular mechanisms to enhance gut health, ileal biochemical profiles were investigated by using metabolomics. The results demonstrated clear effects of dietary magnolia on host physiological response and gut microbiota produced metabolites in chickens particularly those related to amino acids, peptides, fatty acids, and nucleosides. Future studies are warranted to demonstrate the effects of various metabolites affected by MBE treatment on the growth promoting properties.