|Lee, Kyung Woo - U.s. Department Of Agriculture (USDA)|
|Kim, Duk Kyung - U.s. Department Of Agriculture (USDA)|
|Jang, Seung Ik - U.s. Department Of Agriculture (USDA)|
|Lee, Syng Hyen - U.s. Department Of Agriculture (USDA)|
Submitted to: Journal of Animal and Feed Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2014
Publication Date: 12/18/2014
Publication URL: http://handle.nal.usda.gov/10113/61659
Citation: Lee, K., Kim, D., Lillehoj, H.S., Jang, S., Lee, S. 2014. Immune modulation by Bacillus subtilus-based direct-fed microbials in commercial broiler chickens. Journal of Animal and Feed Sciences. 200:76-85.
Interpretive Summary: The development of alternatives to antibiotics is becoming the mainstream topic for animal science research involved in developing sustainable animal production systems. Direct-fed microbials (DFMs), also known as probiotics, have been successfully used to improve the balance of gut microflora and to improve animal growth. ARS scientists in collaboration with private industry partner previously showed that the dietary feeding of young broilers with spores of Bacillus subtilis (B. subtilis) from hatch enhanced innate immunity and improved protection against a parasitic disease in poultry. In this paper, ARS scientists collaborated with scientists in Korean universities to show the underlying biological basis for the beneficial effects of DFM in growing chickens. When young chickens were fed with DFM-supplemented diet from hatch, they showed significant changes in the production of immune modulating proteins that enhanced protection against chickens when they were exposed to bacteria that causes a serious infection, Necrotic enteritis (NE) in the gut. These results indicate that dietary B. subtilis is an effective growth-promoting dietary supplement to increase growth and augment the innate immune response in broiler chickens. This new information will help the poultry industry to understand the biology underlying the benefit of bacterial probiotics and to formulate a novel way of reducing the negative effects of NE which causes considerable economic impact in the poultry industry worldwide.
Technical Abstract: Direct-fed microbials (DFMs), also known as probiotics, have been successfully used to improve the balance of gut microbiota. Spores of Bacillus subtilis, have been used as DFMs for food animals and humans and our previous studies showed that dietary supplementation of broiler chickens with a B. subtilis DFM from hatch enhanced innate immunity and improved protection against avian coccidiosis. In two experiments, we investigated the effects of dietary B. subtilis-based DFM on growth performance and host humoral immune response to Eimeria spp. and Clostridium perfringens, and evaluated B. subtilis-induced global gene expression changes in broiler chickens. Day-old broiler chickens were fed diets with or without DFMs for 28 days starting from hatch. At 14 and 28 days post-hatch, broiler chickens fed the DFM-enriched diet gained significantly more weight (P<0.05) compared with the control diet-fed chickens. Broiler chickens fed diet containing DFM exhibited a significant decrease (P=0.033) in Eimeria- and C. perfringens necrotic enteritis B-like (NetB) toxin-specific serum antibodies compared with those fed a control diet at day 28. The levels of transcripts encoding interleukin (IL) 1ß, IL12 and interferon-' were greater (P=0.004) in the DFM-fed chickens compared with the control chickens. In order to better understand B. subtilis-induced molecular changes associated with improved innate immunity, mRNA was isolated from mid-intestine of DFM-fed chickens for global microarray analysis. Dietary DFMs induced considerable changes in transcriptional expression in intestine, and biofunctional analysis identified 37 genes related with “Inflammatory Response”. These results indicate that dietary B. subtilis DFM is an effective growth-promoting dietary supplement to increase growth and augment innate immune response in broiler chickens. Further study is needed to investigate the mechanism mediated by dietary DFMs to enhance protective innate immunity in a disease model (i.e., necrotic enteritis) which causes considerable economic impact in the poultry industry worldwide.