Allium hookeri supplementation improves intestinal immune response against necrotic enteritis

Authors: LEE, YOUNGSUB - US Department Of Agriculture (USDA); LEE, SUNG-HYEN - Jeollabuk-Do Center; GADDE, UJVALA - US Department Of Agriculture (USDA); OH, SUNGTAEK - US Department Of Agriculture (USDA); LEE, SUNG-JIN - Kangwon National University; Lillehoj, Hyun

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2017
Publication Date: 4/1/2018
Citation: Lee, Y., Lee, S., Gadde, U.D., Oh, S., Lee, S., Lillehoj, H.S. 2018. Allium hookeri supplementation improves intestinal immune response against necrotic enteritis. Poultry Science. 97(6):1899-1908. https://doi.org/10.3382/ps/pey031.
DOI: https://doi.org/10.3382/ps/pey031

Interpretive Summary: Antibiotics are commonly used in animal industry to promote growth and prevent disease and pathogen, as well as to treat sick animals. However, concerns about increasing antibiotic resistance and emergence of superbugs led to governmental bans on antibiotics for growth promotion (AGPs). Therefore, there is a timely need to develop an alternative strategy to reduce antibiotics in animal production. In this paper, ARS scientists collaborated with South Korean scientists to evaluate novel plant-derived phytochemicals as an antibiotic alternative to reduce negative effects of necrotic enteritis (NE) which is causing significant economic losses to poultry industry. NE is a widespread disease in broilers with considerable financial relevance, because it costs the US poultry industry over six billion dollars annually. NE can easily occur in modern, high-intensity poultry farming where feeding environments require high nutrition intake in a short amount of time. Modulation of innate immunity using natural foods, including extracts from medicinal plants offers a new opportunity to enhance poultry health and mitigates the negative effects of intestinal infection like NE. In this study, plant extracts from Allium hookeri (AH) which is found in China were used to supplement poultry diet to feed newly hatched chickens. The results provided the first scientific evidence that Allium hookeri (AH) diet caused enhanced resistance against experimental NE challenge infection. Furthermore, AH-fed chickens showed significantly higher immune activities which correlated with enhanced NE disease resistance. These findings will lead to new feed additive that can reduce the use of antibiotics in poultry production.

Technical Abstract: Three hundred birds (d1 of age) were randomly assigned to 6 groups (n =50 birds/treatment) and fed a basal diet (control) or basal diet supplemented with Allium hookeri (AH) root (1 or 3%). At day14, half of the birds in each group were orally challenged with E. maxima 41A (1 × 104 cells/chicken), followed by C. perfringens infection (1 × 109 CFU/chicken) on day18. Necrotic enteritis (NE)-associated infections and intestinal immune response were assessed by average body weight gain, lesion score and oocyst shedding. The effect of dietary supplementation AH on transcript levels of pro-inflammatory cytokines, tight junction and mucin protein in the jejunum were quantified by qRT-PCR. At day 20, birds fed with diet supplementation 3_ % of AH significantly weighted more than the control group. Although the NE-challenged had significantly reduced average body weight gain, there was no significant the effect between diet × NE-challenge interaction on the average body weight gain. Among the NE-challenged groups, gut lesion score and oocyst shedding were significantly decreased in birds given AH (1 or 3%) compared to the control group. There was a correlation between diet and NE infection in regards to interleukin (IL)-17a, and inducible nitric oxide synthase (iNOS). The up-regulated transcript levels of cytokines IL-8, IL-17a, iNOS, and LITAF by NE challenged groupswere significantly reduced by AH (1 or 3%) supplementation. Down-regulated expression levels of tight junction (TJ) proteins: junctional adhesion molecule 2 (JAM2), occluding, and intestinal mucin 2 (MUC2) by NE challenge was up-regulated by the addition of AH (1 or 3%) supplementation. All TJ proteins (JAM2, ZO1, Ocluddin and MUC2) in the jejunum had a significant diet × NE-challenge interaction. These findings demonstrated that dietary supplementation of AH in chicken feed could be beneficially used to improve chicken health against NE.