About

Yuhua Farnell is an Instructional Associate Professor in the Department of Poultry Science at Texas A&M University. Her research focuses on Avian Stem Cell Biology and Immunology. She is a member of Texas A&M AgriLife, which includes the Texas A&M AgriLife Extension Service, Texas A&M AgriLife Research, and other related entities. Her office is located in Kleberg 352A, and her contact information includes the phone number 979-847-7346 and an email address. Farnell's work contributes to the advancement of poultry science through her research and academic activities within the College of Agriculture & Life Sciences.

Research topics

• Biology
• Medicine
• Microbiology
• Internal medicine
• Immunology
• Cell biology
• Gastroenterology
• Molecular biology
• Pathology

Selected publications

• Evaluation of powdered disinfectants to reduce bacterial contamination of footwear

  The Journal of Applied Poultry Research · 2025-12-03

  articleOpen access

  Footwear is a known route for spreading microorganisms to farms and between poultry houses. While disinfectant foot pans are commonly used, liquid products lose efficacy when organic matter such as feces or litter is present. This study evaluated powdered peracetic acid, sodium percarbonate, quaternary ammonium compound, and bleach disinfectants for their ability to reduce bacteria on contaminated boot molds under heavy organic loads. Each product was evaluated individually by inoculating concrete boot molds in plastic boot covers with layer manure and tested a short versus long contact time. Microbial loads of total aerobes, Staphylococci , and coliforms were enumerated after treatment. Results indicated that all four products reduced microbial loads compared to rinsing only, suggesting successful use even with short contact times. Efficacy of the sodium percarbonate and quaternary ammonium compounds were more time dependent, while the peracetic acid and bleach products were less so. Powdered disinfectants offer a viable alternative to liquid foot pans, but product selection may need to be tailored to meet individual farm needs.

  PublisherDOI

• Black Cumin (Nigella sativa) as a Healthy Feed Additive for Broiler Production: A Focused Review

  Poultry · 2025-10-10

  articleOpen accessCorresponding

  Following restrictions on antibiotic growth promoters in poultry production, there is growing interest in natural feed additives that support health and productivity. Among these, black cumin (Nigella sativa) has emerged as a promising candidate due to its antioxidant, antimicrobial, and immunomodulatory properties. Most studies report that black cumin, in the form of whole seeds, seed meal, or seed oil, improves body weight gain and feed conversion ratio, enhances antioxidant and immune status, and provides additional benefits on lipid profiles, liver enzymes, and cecal microbial balance. This review provides a focused synthesis of recent studies (2014–2025) on black cumin supplementation in broiler chickens, considering its various forms (whole seeds, seed meal, seed oil, and nano-formulations) and production contexts (healthy, heat-stressed, and disease-challenged birds). Specifically, this review compares responses across different forms and doses, evaluates effects on growth performance, immune function, gut health, antioxidant status, liver metabolism, and meat and carcass quality, and highlights inconsistencies among studies. Additionally, it identifies key research gaps to guide future investigations, including optimal dosing, long-term safety, and practical applications in commercial production. Overall, black cumin shows potential as a natural alternative to antibiotics, but further standardized, large-scale studies are needed to confirm its efficacy and feasibility in sustainable poultry farming.

  PublisherOA PDFDOI

• Evaluation of a prebiotic mannan-oligosaccharide on Salmonella Enteritidis cecal colonization and immune response of broiler chickens

  Poultry Science · 2025-10-01 · 1 citations

  articleOpen access

  Salmonella causes 1.35 million cases of foodborne illness in the United States annually. We hypothesized that the administration of ActiveMOS®, a prebiotic mannan-oligosaccharide (MOS) product, would reduce Salmonella Enteritidis (SE) cecal colonization and improve immune function in young broilers. The objectives of this study were to assess the effects of MOS on SE cecal colonization, serum cytokines, lipopolysaccharide (LPS), and immunoglobulin M (IgM). This study consisted of two independent 14 d trials. Day-of-hatch broilers (n = 240/trial) were evenly distributed across eight floor pens and randomly assigned to four treatments. Treatments were as follows: control (0.0), 1.0, 1.5, and 2.0 kg of MOS/metric ton (MT) of feed. Broilers were orally gavaged with PBS for unchallenged treatments or SE for challenged treatments at 7 d of age. Birds were euthanized one week post gavage. Salmonella Enteritidis cecal colonization, serum pro-inflammatory cytokines- interferon gamma (IFNγ), interleukin-2 (IL-2), IL-6, IL-16, IL-21; anti-inflammatory/regulatory cytokines- IFNα, IL-10; chemokines- regulated on activation, normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein-1β (MIP-1β), MIP-3α; colony-stimulating factors- macrophage colony-stimulating factor (M-CSF); and growth factors- vascular endothelial growth factor (VEGF), IgM titers, and LPS concentrations were evaluated. Data were analyzed via a two-way ANOVA with an α = 0.05. In the first trial, Salmonella was significantly reduced by 1.07 and 0.84 log in the 1.5 kg/MT and 2.0 kg/MT MOS inclusions, respectively. In trial two, a significant 1.14 log reduction of SE in the 1.5 kg/MT MOS diet was observed. For unchallenged birds, all MOS treatments decreased IFNα levels. However, in the control basal diet, levels of IFNα were significantly diminished in SE challenged chicks. Decreased expression of IL-16 and MIP-1β was detected (p < 0.05) in SE challenged broilers compared to unchallenged birds. Levels of RANTES were significantly increased in 1.0 kg/MT and 2.0 kg/MT MOS inclusions compared to all other diets. No significant differences were observed with any other cytokines or LPS. The isotype IgM was reduced in all treatments compared to the control diet in both unchallenged and SE challenged birds, suggesting depressed humoral immunity when MOS was fed. Although a mechanism of action was not determined, these data suggest that MOS at the 1.5 kg/MT inclusion was efficacious in reducing SE.

  PublisherDOI

• Fructose induces inflammatory activation in macrophages and microglia through the nutrient‐sensing ghrelin receptor

  The FASEB Journal · 2025-02-22 · 6 citations

  articleOpen access

  Abstract High fructose corn syrup (HFCS) is a commonly used sweetener in soft drinks and processed foods, and HFCS exacerbates inflammation when consumed in excess. Fructose, a primary component of HFCS; however, it is unclear whether fructose directly activates inflammatory signaling. Growth hormone secretagogue receptor (GHSR) is a receptor of the nutrient‐sensing hormone ghrelin. We previously reported that GHSR ablation mitigates HFCS‐induced inflammation in adipose tissue and liver, shifting macrophages toward an anti‐inflammatory spectrum. Since inflammation is primarily governed by innate immune cells, such as macrophages in the peripheral tissues and microglia in the brain, this study aims to investigate whether GHSR autonomously regulates pro‐inflammatory activation in macrophages and microglia upon fructose exposure. GHSR deletion mutants of RAW 264.7 macrophages and the immortalized microglial cell line (IMG) were generated using CRISPR‐Cas9 gene editing. After treating the cells with equimolar concentrations of fructose or glucose for 24 h, fructose increased mRNA and protein expression of GHSR and pro‐inflammatory cytokines ( Il1β , Il6 , and Tnfα ) in both macrophages and microglia, suggesting that fructose activates Ghsr and induces inflammation directly in macrophages and microglia. Remarkably, GHSR deletion mutants ( Ghsr mutant ) of macrophages and microglia exhibited reduced inflammatory responses to fructose, indicating that GHSR mediates fructose‐induced inflammation. Furthermore, we found that GHSR regulates fructose transport and fructose metabolism and mediates fructose‐induced inflammatory activation through CREB–AKT‐NF‐κB and p38 MAPK signaling pathways. Our results underscore that fructose triggers inflammation, and reducing HFCS consumption would reduce disease risk. Moreover, these findings reveal for the first time that the nutrient‐sensing receptor GHSR plays a crucial role in fructose‐mediated inflammatory activation, suggesting that targeting GHSR may be a promising therapeutic approach to combat the immunotoxicity of foods that contain fructose.

  PublisherOA PDFDOI

• Serum cytokine profile of neonatal broiler chickens infected with Salmonella Typhimurium

  Frontiers in Physiology · 2024-02-23 · 8 citations

  articleOpen access

  The avian immune system responds to Salmonella infection by expressing cytokines and chemokines. We hypothesized that the immune status of Salmonella Typhimurium (ST) challenged neonatal broilers would differ from the uninfected treatment. The objective of this experiment was to evaluate 12 cytokines. Day of hatch male chicks were randomly allocated into a control or ST challenged group. At day three of age, sterile diluent or 5.0 × 10 8 CFU of ST was given orally to each chick. Blood was obtained 24 h post challenge and serum separated for later analysis (n = 30 chicks/treatment). Significant ( p ≤ 0.05) increases in pro-inflammatory cytokines -interleukin-6 (IL-6), IL-16, and IL-21; anti-inflammatory cytokines - IL-10; chemokines -regulated on activation, normal T cell expressed and secreted (RANTES), macrophage inflammatory protein-1β (MIP-1β), and MIP-3α; colony stimulating factors -macrophage colony-stimulating factor (M-CSF); and growth factors -vascular endothelial growth factor (VEGF) were observed in the serum of the challenged chicks when compared to the control. No significant differences were observed in IL-2, interferon gamma (IFNγ), and IFNα. These data indicate the detection of mucosal immune responses in broiler chickens following ST infection. The heightened levels of pro-inflammatory cytokines, chemokines, and colony stimulating factors align with known inflammatory mechanisms, like the influx of immune cells. However, the elevation of IL-10 was unexpected, due to its immunoregulatory properties. Notably, the rise in VEGF levels is compelling, as it suggests the possibility of tissue repair and angiogenesis in ST infected birds.

  PublisherOA PDFDOI

• Unraveling frontiers in poultry health (part 1) – Mitigating economically important viral and bacterial diseases in commercial Chicken and Turkey production

  Poultry Science · 2024-02-07 · 1 citations

  articleOpen access

  This symposium offered up-to-date perspectives on field experiences and the latest research on significant viral and bacterial diseases affecting poultry. A highlight was the discussion on the use of enteroids as advanced in vitro models for exploring disease pathogenesis. Outcomes of this symposium included identifying the urgent need to improve the prevention and control of avian influenza by focusing research on vaccine effectiveness. In this regard, efforts should focus on enhancing the relatedness of vaccine antigen to the field (challenge) virus strain and improving immunogenicity. It was also revealed that gangrenous dermatitis could be controlled through withholding or restricting the administration of ionophores during broiler life cycle, and that administration of microscopic polymer beads (gel) based-live coccidia vaccines to chicks could be used to reduce necrotic enteritis-induced mortality. It was emphasized that effective diagnosis of re-emerging Turkey diseases (such as blackhead, fowl cholera, and coccidiosis) and emerging Turkey diseases such as reoviral hepatitis, reoviral arthritis, Ornithobacterium rhinotracheale infection, and strepticemia require complementarity between investigative research approaches and production Veterinarian field approaches. Lastly, it was determined that the development of a variety of functionally-specific enteroids would expedite the delineation of enteric pathogen mechanisms and the identification of novel vaccine adjuvants.

  PublisherDOI

• Innate immunity in peripheral tissues is differentially impaired under normal and endotoxic conditions in aging

  Frontiers in Immunology · 2024-08-16 · 6 citations

  articleOpen access

  Chronic low-grade inflammation is a hallmark of aging, aka "inflammaging", which is linked to a wide range of age-associated diseases. Immune dysfunction increases disease susceptibility, and increases morbidity and mortality of aging. Innate immune cells, including monocytes, macrophages and neutrophils, are the first responders of host defense and the key mediators of various metabolic and inflammatory insults. Currently, the understanding of innate immune programming in aging is largely fragmented. Here we investigated the phenotypic and functional properties of innate immune cells in various peripheral tissues of young and aged mice under normal and endotoxic conditions. Under the steady state, aged mice showed elevated pro-inflammatory monocytes/macrophages in peripheral blood, adipose tissue, liver, and colon. Under lipopolysaccharide (LPS)-induced inflammatory state, the innate immune cells of aged mice showed a different response to LPS stimulus than that of young mice. LPS-induced immune responses displayed differential profiles in different tissues and cell types. In the peripheral blood, when responding to LPS, the aged mice showed higher neutrophils, but lower pro-inflammatory monocytes than that in young mice. In the peritoneal fluid, while young mice exhibited significantly elevated pro-inflammatory neutrophils and macrophages in response to LPS, aged mice exhibited decreased pro-inflammatory neutrophils and variable cytokine responses in macrophages. In the adipose tissue, LPS induced less infiltrated neutrophils but more infiltrated macrophages in old mice than young mice. In the liver, aged mice showed a more robust increase of pro-inflammatory macrophages compared to that in young mice under LPS stimulation. In colon, macrophages showed relatively mild response to LPS in both young and old mice. We have further tested bone-marrow derived macrophages (BMDM) from young and aged mice, we found that BMDM from aged mice have impaired polarization, displaying higher expression of pro-inflammatory markers than those from young mice. These data collectively suggest that innate immunity in peripheral tissues is impaired in aging, and the dysregulation of immunity is tissue- and cell-dependent. Our findings in the rodent model underscore the complexity of aging immunity. Further investigation is needed to determine whether the immune profile observed in aged mice is applicable in age-associated diseases in humans.

  PublisherOA PDFDOI

• Distillers dried grains with soluble and enzyme inclusion in the diet effects broilers performance, intestinal health, and microbiota composition

  Poultry Science · 2023-08-08 · 17 citations

  articleOpen access

  This study tested the effect of distillers dried grains with soluble (DDGS) inclusion in a broiler diet, with or without supplementation of exogenous enzymes, on the microbiota composition, intestinal health, diet digestibility and performance. A total of 288 one-day-old chickens was assigned to 6 treatments (8 replicate of 6 birds each) according to a completely randomized design with a 3 × 2 factorial scheme with 3 DDGS levels (0, 7 and 14%) and 2 inclusions of exogenous enzymes (with or without a multicarbohydrase complex + phytase [MCPC]). The results exhibited that DDGS inclusion up to 14% did not impair broilers performance up to 28 d, however, DDGS-fed animals exhibited significant improvement with the MCPC supplementation. No effects of the enzymes in the ileal digestibility were found at 21 d. DDGS inclusion in the diet affected dry matter and gross energy digestibility. Broilers fed diets with MCPC were found to have less intestinal histological alteration thus better gut health. No effect of DDGS, enzyme or interaction of those were observed for intestinal permeability and in the serum inflammatory biomarker (calprotectin) at 7 and 28 d. The increase of DDGS percentage in the diet reduced the diversity of the ileal microbiota but increased the cecal microbiota diversity. The inclusion of DDGS showed positive effects on microbiota composition due to a reduction of Proteobacteria phylum in the ileum at 28d and a reduction in the presence of Enterococcaceae family in the ileum at 14 and 28d. The inclusion of MCPC complex might promote beneficial changes in the ileal and cecal microbiota due reduce of Proteobacteria, Bacillaceae and Enterobacteriaceae. The supplementation of xylanase, β-glucanase, arabinofuranosidase and phytase to a DDGS diet improves performance and intestinal health allowing the use of these subproduct in the poultry nutrition.

  PublisherDOI

• Bacitracin Supplementation as a Growth Promoter Down-Regulates Innate and Adaptive Cytokines in Broilers’ Intestines

  Poultry · 2023-08-29 · 2 citations

  articleOpen access

  In the past decade, the withdrawal of antibiotics used as growth promoters (AGP) has increased some poultry industry challenges, such as the rise of intestinal diseases. Experts advocate that AGPs improve performance due to the modulation of the intestinal microbiota, with resulting anti-inflammatory effects. However, the impact and interactions of AGPs with the host intestinal immune system are still unknown, which represents issues in developing effective alternatives for AGPs. Therefore, this study was aimed at better understanding the potential mechanism of action of bacitracin used as AGP and its impacts on the intestinal immune system. Ninety day-of-hatch chickens were randomly assigned to two treatments with three repetitions of fifteen birds, a control (CNT) group with a corn/soybean meal standard diet, and a control diet supplemented with 50 g/ton of feed of bacitracin (BMD). The cytokines’ and chemokines’ production (IFN-α, IFN-γ, IL-16, IL-10, IL-21, IL-6, M-CSF, MIP-3α, MIP-1β, VEGF and CCL-5) were assessed in the jejunum and ileum at 14, 21, 28 and 36 days of age by using a chicken-specific cytokine/chemokine peptide ELISA array. Broilers with BMD supplementation were found to have a lower production of IL-16, IFN-γ, M-CSF, IL-21, MIP-1β and VEGF in the jejunum at 14 d. However, from 21 through 36 days, the effect of BMD on cytokine production in the jejunum was negligible except for CCL-5, which was reduced at D36. In the ileum, BMD effects on the cytokine profile started at 28 d, when BMD-supplemented broilers showed a reduced IL-6 production level. At day 36, BMD reduced IL-16 and MIP-3α production but increased VEGF concentration in the ileum tissue. The present study demonstrated that the use of bacitracin as an AGP modulates the small intestine immune system, especially in the first phase of the broiler’s life (up to 14 days). Moreover, BMD anti-inflammatory effects include not only innate immunity but also seemed to influence the development of the adaptive immune response as seen by the decreased production of IL-21 and IL-16. These results demonstrate that a commonly used AGP in broiler feed had a local anti-inflammatory effect.

  PublisherOA PDFDOI

• INFLAMM-AGING IS ASSOCIATED WITH PRO-INFLAMMATORY PROGRAMMING OF INNATE IMMUNE CELLS IN THE COLON

  Innovation in Aging · 2022-11-01 · 2 citations

  articleOpen access

  Abstract Chronic low-grade inflammation is prevalent in aging, which is called inflamm-aging. Immune cells are important mediator of inflammatory state of host and the innate immunity is the first responder to various insults. Gastrointestinal track, especially colon, is the site where immune cells are abundant. Aging is associated with increased gut dysbiosis and functional decline. We hypothesize that colonic innate immune cells contribute to the age-associated inflammation in the colon. We found that macrophages in colon mucosa are elevated in aging, and it is accompanied by pro-inflammatory cytokine expression and increased gut permeability. Specifically, we used flow cytometry to assess colonic innate immune cells collected from 5-, 7-, 14-, 19-, 24-, and 28-month-old mice. Aging significantly increased the populations of pro-inflammatory cytokine producing innate immune cells in the colon, including neutrophils, dendritic cells, monocytes and macrophages. Interestingly, the infiltrating Ly6Chi macrophages and pro-inflammatory CD11c+ macrophages were much higher, while anti-inflammatory CD206+ macrophages were decreased in colon of the aged mice. In line with the immune profile, aged mice showed increased gut permeability tested by fluorescein isothiocyanate-dextran, and the gene expressions of gap junction proteins in the colon were decreased, supporting increased gut permeability in the aged mice. Collectively, our results suggest that innate immune cells play an importance role in age-associated gut inflammation; targeting the innate immune cells in the colon may present a novel therapeutic strategy for prevention and treatment of aging leaky gut.

  PublisherOA PDFDOI

Frequent coauthors

• David J. Earnest

  20 shared

• J.A. Byrd

  Southern Plains Agricultural Research Center

  19 shared

• Gregg C. Allen

  Texas A&M University

  18 shared

• Michael H. Kogut

  Southern Plains Agricultural Research Center

  17 shared

• M.B. Farnell

  14 shared

• Kenneth J. Genovese

  Southern Plains Agricultural Research Center

  13 shared

• Nichole Neuendorff

  Texas A&M Health Science Center

  12 shared

• Dan Zhao

  Henan University

  10 shared