The effect of a unique phytochemical mixture to enhance host response to poultry coccidiosis

Authors: Park, Inkyung; Nam, Hyoyoun; RAVICHANRAN, SRIPATHY - Avt Natural North America; WALL, EMMA - Nutreco; Lillehoj, Hyun

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2025
Publication Date: 3/15/2025
Citation: Park, I.N., Nam, H., Ravichanran, S., Wall, E., Lillehoj, H.S. 2025. The effect of a unique phytochemical mixture to enhance host response to poultry coccidiosis. Poultry Science. 104(5). Article e105042. https://doi.org/10.1016/j.psj.2025.105042.
DOI: https://doi.org/10.1016/j.psj.2025.105042

Interpretive Summary: Development of alternative strategies to reduce the use of dietary antibiotics in poultry production is a high priority for animal health program. In this report, we show that a unique combination of three phytochemicals from natural plants such as clove essential oil, oregano essential oil, and cinnamon essential oil will be a safe dietary feed additive to young broiler chickens based on their unique ability to reduce harmful inflammatory responses and reduce intestinal permeability in chickens infected with coccidiosis, an intestinal parasitic disease caused by Eimeria parasites that destroy intestinal tissues with resulting body weight losses and sometimes, death. Due to the restriction on the use of antibiotics in the animal feed, development of novel feed additives that can enhance animal growth and mitigate disease response in young chickens will enhance poultry production and reduce economic losses due to parasitic infections. The results of this study showing the beneficial effects of three novel combination of plant-derived feed ingredients as a non-antibiotic feed additive for commercial poultry production will have a major impact on poultry industry.

Technical Abstract: This study was conducted to investigate the effects of a phytochemical mixture (PHY) on the growth performance, intestinal immunity, and intestinal integrity of broilers infected with coccidiosis. In in vitro experiments, the cytotoxicity of PHY was evaluated using an MTT assay on chicken macrophage cells (CMCs), chicken intestinal epithelial cells (IECs), quail muscle cells (QMCs), and embryonic chicken breast muscle cells (EMCs). In CMCs, inflammation was induced with 1.0 µg/mL LPS, followed by culturing with PHY at three concentrations (1.0, 10.0, and 100 µg/mL) and measuring the gene expression levels of IL-1ß and IL-8. In IECs, PHY was added and cultured, and the gene expression levels of occludin, ZO-1, and MUC2 were measured. For QMCs and EMCs, the 10% FBS concentration used in the cell proliferation stage was reduced to 0.5% and 2.0%, respectively, to induce cell differentiation, followed by culturing with PHY and measuring the gene expression levels of Pax7 and MyoG. Additionally, the antimicrobial ability of PHY against the oocysts of Eimeria tenella (E. tenella) or Clostridium perfringens (C. perfringens) was evaluated. In the in vivo experiment, one hundred and twenty male broiler chickens (0-day-old) were allocated into three treatment groups: (1) basal diet without infection (NC), (2) basal diet with E. maxima infection (PC), and (3) PHY at 4.5 mg/kg feed with E. maxima infection (PHY). Body weight (BW) was measured on days 0, 7, 14, 20, and 22. PC and PHY groups were orally infected with E. maxima on day 14. Jejunal samples on day 22 were collected to conduct gene expression analysis of cytokines, TJ proteins, and antioxidant enzymes. In vitro, PHY at concentrations below 0.1 mg/mL showed no cytotoxicity in CMCs, IECs, QMCs, and EMCs. PHY significantly decreased IL-1ß and IL-6 in CMCs and increased ZO-1 and MUC2 in IECs in a dose-dependent manner. PHY concentrations of 0.5 mg/mL or higher reduced the survival rate of oocysts of E. tenella and C. perfringens to below 50%, but these concentrations are unsuitable for use as feed additives at 10-100 times higher. In the E. maxima-infected groups, dietary PHY tended to mitigate BW loss due to infection. Upon infection, proinflammatory cytokines were suppressed in the PHY group compared to the PC group. Dietary PHY also increased the expression of occludin and JAM-2. However, PHY did not reduce the oocyst number in infected chickens. These results suggest that dietary PHY supplementation has the potential to enhance intestinal immunity and permeability at the host level, thereby mitigating the productivity-depressing effects in broilers infected with E. maxima, not due to its direct antimicrobial effects, but rather due to gut physiological responses. This indicates its potential as a new feed additive, providing an ideal solution to antibiotic resistance issues as an alternative to antibiotics.