Herbal Anticoccidial Blend Keeps Broiler Blood Chemistry Stable During Eimeria Challenge

A six-plant herbal supplement may offer poultry producers a gentler way to…

The economic stakes behind this research are considerable. Coccidiosis remains one of the costliest parasitic diseases in modern poultry production, with estimates placing global losses at roughly 10.4 billion GBP in 2016, and other analyses suggesting annual losses approaching 3 billion USD. These figures reflect not only mortality but also the subtler costs of subclinical infection: impaired feed conversion, uneven growth, reduced nutrient absorption, and the downstream expense of managing outbreaks. Because the parasite damages the intestinal epithelium, even mild infections can compromise the digestive efficiency that underpins the profitability of broiler operations, which is why prevention rather than treatment has long been the industry standard.

Prevention, however, has historically depended on chemical coccidiostats, and the sustainability of that approach is increasingly in question. Decades of continuous use have selected for drug-resistant Eimeria strains, and residues in meat products have drawn regulatory scrutiny in many markets. Within the European Union, where this study was conducted, pressure to reduce routine antimicrobial and antiparasitic use has intensified, pushing producers toward vaccination, husbandry improvements, and feed additives of natural origin. Herbal supplements occupy a particularly interesting niche in this landscape because many plant-derived compounds combine antimicrobial, antioxidant, and immunomodulatory activities, meaning they may support the host rather than simply suppress the parasite.

The design of the present experiment reflects this commercial reality in an important way. Rather than including a completely untreated control group, the researchers compared a standard chemical anticoccidial program against an herbal alternative, mirroring the choices actually available to working poultry producers. The four-group structure, with infected and non-infected birds on each treatment, allowed the investigators to separate the effects of infection itself from the effects of the additive, a distinction that matters greatly when interpreting blood-based biomarkers. The inclusion of two separate but identical poultry houses further guarded against cross-contamination between infected and uninfected flocks, a common pitfall in Eimeria challenge studies.

The choice of blood-based endpoints deserves particular attention. Most previous work on herbal anticoccidials has emphasized growth performance, feed intake, and intestinal lesion scores, which are undeniably practical measures but say little about how the animal’s physiology is coping internally. Serum biochemistry offers a window into organ function and metabolic status: enzymes such as ALT, AST, and GGT can signal hepatic stress or damage, while total protein, albumin, urea, calcium, iron, and magnesium concentrations reflect nutritional status, kidney function, and the acute-phase response to inflammation. Hematology complements this picture, since the leukogram captures how the immune system is mobilizing its cellular forces in response to parasitic invasion.

Among the hematological findings, the differential leukocyte profile is especially informative in birds. Unlike mammals, chickens rely heavily on heterophils rather than neutrophils as their primary granulocyte in innate defense, so shifts in the ratio of band to segmented heterophils can indicate the intensity and maturity of an inflammatory response. The significant differences observed among groups in band heterophils, segmented heterophils, lymphocytes, and monocytes suggest that the infection and the dietary treatments each left distinguishable fingerprints on the circulating immune cell population. Monocytes, which serve as precursors to macrophages at sites of intestinal damage, are particularly relevant in coccidiosis, where tissue repair and parasite clearance both depend on phagocytic activity.

The morphological assessment of lymphocytes represents one of the more novel dimensions of this work. Lymphocyte morphology is rarely reported in broiler nutrition studies, yet changes in cell size, cytoplasmic characteristics, and nuclear features can reflect activation states, stress responses, or immunological challenge. The finding that lymphocyte morphology differed significantly among groups and sampling periods indicates that the herbal additive, the chemical anticoccidial, and the infection itself each shaped the appearance of these key adaptive immune cells. This adds a layer of biological detail that goes beyond simple cell counts and may help explain how plant-derived compounds modulate immune function during parasitic infection.

The temporal dimension of the study also merits consideration. Blood samples were collected on days 10 and 35, capturing two very different physiological windows. Day 10 falls shortly after the day-7 Eimeria challenge, when the acute phase of infection and the initial immune response would be underway, while day 35 coincides with the end of the standard broiler rearing period, when birds have largely matured both immunologically and metabolically. The significant effect of age on total protein, albumin, AST, GGT, calcium, and iron concentrations is consistent with the well-documented developmental changes that occur as chicks grow, including the maturation of hepatic function and the shifting demands of skeletal growth and feather development.

The significant group effects on ALT activity and magnesium concentration, together with the group-by-age interaction for urea, hint at subtle metabolic adjustments rather than overt toxicity. That no adverse changes in physiological condition were observed is a key takeaway, since any novel feed additive must first demonstrate safety before its efficacy can be meaningfully evaluated. The liver enzymes in particular are closely monitored in feed additive trials because the liver is the primary site of xenobiotic metabolism, and stable ALT and AST values across treatment groups would suggest that the herbal formulation is well tolerated at the inclusion rate tested.

The composition of the herbal supplement itself provides context for its biological activity. The six plant components represent a blend of botanicals with long histories in traditional medicine and growing bodies of modern pharmacological research. Berberis aristata is a rich source of berberine, an isoquinoline alkaloid with documented antimicrobial and anti-inflammatory properties. Allium sativum, common garlic, contributes organosulfur compounds with antioxidant and immunostimulatory effects. Azadirachta indica, or neem, contains limonoids such as azadirachtin that have been studied for antiparasitic activity across multiple species. Holarrhena antidysenterica has a long tradition of use against dysentery and intestinal parasites, Ficus religiosa contributes polyphenolic constituents, and Embelia ribes contains embelin, a benzoquinone with reported anthelmintic and antimicrobial properties. Together, these botanicals deliver a spectrum of alkaloids, phenolics, sulfur compounds, and quinones that could plausibly act on both the parasite and the host’s immune and oxidative stress pathways.

The multi-component nature of such formulations is worth emphasizing, because it distinguishes them from single-molecule drugs. Where a chemical coccidiostat typically targets one specific parasite pathway, a mixture of plant extracts presents multiple active constituents that may act synergistically, potentially slowing the emergence of resistance and offering broader activity across the various Eimeria species that infect broilers. This polypharmacological profile is often cited as an advantage of herbal approaches, though it also complicates standardization, quality control, and regulatory approval, since the potency of plant material can vary with growing conditions, harvest timing, and processing methods.

From a practical standpoint, the inclusion rate of 500 grams per tonne of feed is notable because it positions the herbal additive as a complete replacement for conventional coccidiostats rather than a supplementary measure. This is a meaningful distinction for producers considering withdrawal of chemical anticoccidials, whether due to consumer demand, export market requirements, or the development of resistance in their local parasite population. Demonstrating that birds receiving the herbal supplement maintained biochemical and hematological parameters comparable to those on conventional drugs, even under experimental infection pressure, provides evidence that such a substitution can be physiologically neutral or beneficial.

The Ross 308 genetic line used in this study is the most widely deployed broiler strain in European production, which strengthens the relevance of the findings to commercial settings. The birds were reared under stocking densities compliant with Council Directive 2007/43/EC, and the study protocol was reviewed and approved by an institutional bioethics committee in accordance with European Directive 2010/63/EU, reflecting the regulatory standards that govern animal research within the European Union. These methodological details matter because they establish that the results were obtained under conditions that approximate both legal requirements and real-world husbandry practice.

Looking ahead, the biochemical and hematological data generated here could serve as a baseline for future studies that integrate these blood-based markers with direct measures of parasite burden, intestinal lesion scoring, oocyst shedding, and growth performance. Such integrated approaches would help clarify whether the observed changes in leukocyte profiles and lymphocyte morphology translate into meaningful differences in disease resistance or recovery. They would also help determine optimal inclusion rates, identify which of the six botanical components contribute most to the observed effects, and establish whether the benefits persist across different Eimeria species and challenge severities. As the poultry industry continues its transition toward reduced reliance on conventional anticoccidial drugs, studies that document the physiological consequences of such substitutions at the level of blood chemistry and immune cell biology will be essential for building the evidence base that producers, veterinarians, and regulators need to make informed decisions.

Subject of Research: Effects of a herbal anticoccidial feed additive on serum biochemistry and blood cell profiles of broiler chickens during experimental Eimeria infection.

Article Title: Serum biochemical and hematological responses of broiler chickens to herbal-origin anticoccidial supplementation during experimental Eimeria infection

Article References: Vilienė, V., Racevičiūtė-Stupelienė, A., Murawska, D., Gesek, M., Matusevičius, P., Miknienė, Z., & Nutautaitė, M. (2026). Serum biochemical and hematological responses of broiler chickens to herbal-origin anticoccidial supplementation during experimental Eimeria infection. Frontiers in Veterinary Science, 13, Article 1961791. https://doi.org/10.3389/fvets.2026.1961791

Image Credits: AI Generated

DOI: 10.3389/fvets.2026.1961791

Keywords: poultry, coccidiosis, Eimeria, broiler chickens, herbal feed additive, serum biochemistry, hematology, lymphocyte morphology, immune response, phytogenic compounds, Serum, biochemical