A humble tree leaf from northern China may hold the key to keeping hens laying through one of the most damaging assaults their bodies can face. In a study published in the journal Stress Biology, researchers at Northwest A&F University in Yangling, China, report that a dietary supplement made from the leaves of Acer truncatum, the purpleblow maple, protected laying hens from oxidative-stress-induced collapse of ovarian function. The work, led by Kailong Qin and Junjie Ma under the supervision of Xiaojun Yang, offers one of the most detailed molecular pictures yet of how a plant-derived feed additive can simultaneously rebuild antioxidant defenses, restore reproductive hormones, and repair the delicate vascular network that sustains egg formation.
The stakes are considerable for the poultry industry. Modern laying hens are biological machines optimized for extraordinary output, producing an egg nearly every day, and that productivity depends on an ovary in constant, high-turnover motion. Follicles are recruited, grown, and ovulated in rapid succession, a process that demands enormous energy, a rich blood supply, and tight hormonal orchestration. It is also a process exquisitely vulnerable to reactive oxygen species. When oxidative stress tips the balance, follicles die off in a process called atresia, hormone levels fall, and laying performance plummets. Because consumers and regulators increasingly demand reductions in synthetic additives, the search for natural, sustainable interventions has become urgent within the One Health framework that links animal, human, and environmental well-being.
To model that stress in a controlled way, the team injected hens with tert-butyl hydroperoxide, or tBHP, a chemical oxidant widely used to induce reproducible oxidative damage in animal studies. Thirty healthy Hy-Line Brown hens were randomly divided into three groups of ten. A control group received a basal diet and saline injections. A stressed group received the basal diet plus tBHP injections every four days for 28 days. The third group received the same tBHP challenge but ate a diet supplemented with 0.6 percent Acer truncatum leaf extract, or ATLE, a preparation exceptionally rich in polyphenols and flavonoids. Over the four-week trial, the researchers tracked egg production, feed efficiency, ovarian anatomy, blood hormones, antioxidant markers, angiogenic factors, and, crucially, the full transcriptomic landscape of the ovary.
The results were striking. Oxidative stress alone drove laying rates down, pushed the feed conversion ratio up, and reduced average daily feed intake, exactly the pattern seen when hens divert resources from reproduction toward survival. It also shrank the pool of hierarchical follicles, the large preovulatory follicles destined for ovulation, and lowered the ovarian stroma index, a measure of the functional tissue supporting follicle development. Histological sections revealed more atretic follicles and necrotic inflammatory foci in the stressed ovaries. Serum concentrations of luteinizing hormone and growth hormone fell, disrupting the hypothalamic-pituitary-gonadal axis that governs follicle recruitment. In hens fed the maple leaf extract, however, nearly all of these parameters rebounded. Laying rate and feed efficiency recovered, hierarchical follicle numbers and stroma index were preserved, and LH and GH concentrations rose significantly compared with the stressed, unsupplemented birds.
The molecular engine behind this rescue appears to be the Nrf2 pathway, the master switch of cellular antioxidant defense. Under normal conditions, the transcription factor Nrf2 is held inactive by its suppressor Keap1; when oxidative pressure rises, Nrf2 escapes, migrates to the nucleus, and switches on a battery of cytoprotective genes. In the stressed hens, the expression of Nrf2 and its downstream targets, including SOD3, GPX3, PRDX4, GSR, and CAT, was significantly suppressed. ATLE supplementation reversed this shutdown, and the biochemical consequences were measurable in both blood and ovarian tissue: superoxide dismutase and catalase activities climbed, while malondialdehyde, a lipid peroxidation product that serves as a fingerprint of oxidative damage, dropped. The authors propose that the extract’s flavonoids and polyphenols act either by directly scavenging reactive oxygen species or by modulating the Keap1-Nrf2 interaction, consistent with prior work showing that resveratrol, theabrownin, and other plant compounds preserve reproductive function through the same axis.
Perhaps the most novel finding concerns blood vessels. Follicle growth is angiogenesis-dependent: each developing follicle must be wrapped in a network of new capillaries that deliver nutrients, oxygen, and hormones. Oxidative stress damages vascular endothelial cells and disrupts hypoxia signaling, suppressing key angiogenic factors such as vascular endothelial growth factor and angiopoietin 1. In the stressed hens, ovarian protein levels of VEGF, ANGPT1, and HIF-1α all fell, along with mRNA expression of VEGFA, ANGPT1, ANGPT2, ITGA5, and MMP9. ATLE supplementation restored these factors, suggesting the extract did more than passively mop up free radicals; it appeared to actively support the reconstruction of a functional vascular scaffold within the ovary. This aligns with known actions of related phytochemicals, such as quercetin promoting angiogenesis through PI3K/Akt signaling and resveratrol stimulating endothelial migration via SIRT1/HIF-1α pathways.
The transcriptomic analysis tied these threads together into a systems-level picture. RNA sequencing of ovarian tissue identified 4,191 differentially expressed genes under oxidative stress and 1,373 genes shifted by ATLE supplementation. The overlap was striking: 91.9 percent of the genes altered by the extract were also among those damaged by oxidative stress, and more than 88 percent of the enriched Gene Ontology terms overlapped between the two comparisons. In other words, the extract appeared to reverse the damage almost point for point. Pathway analysis showed that both injury and repair converged on extracellular matrix organization, focal adhesion, and ECM-receptor interaction, the structural infrastructure that allows endothelial cells to migrate and vascular networks to form. Genes encoding collagens, laminin, fibronectin, and the VEGF receptor KDR were all suppressed by stress and restored by the extract, indicating a coordinated remodeling of the ovarian microenvironment back toward homeostasis.
The study is not without caveats, which the authors acknowledge candidly. The trial lasted only four weeks with ten hens per group, a design well suited to illuminating mechanisms under acute chemical stress but insufficient to predict performance across full commercial laying cycles. ATLE is a complex mixture, and the specific compounds responsible for the effects were not isolated. Most importantly, it remains unresolved whether the extract stimulates angiogenesis directly or whether vascular recovery is simply a secondary benefit of reduced oxidative damage; the interplay between Nrf2 and VEGF signaling has been noted in other contexts, including preeclampsia research. The authors call for endothelial cell models to disentangle cause from effect and for longer trials in production settings.
Even with those limitations, the findings carry real weight for animal agriculture and beyond. They demonstrate that a nutritional intervention can act on multiple signaling axes at once, fortifying antioxidant defenses through Nrf2 while simultaneously preserving the vascular and extracellular matrix architecture that follicles require. They also reinforce a growing theme in reproductive biology: ovarian vascular health, long overlooked, is a central determinant of fertility, and its degradation may underlie reproductive aging in species far beyond the hen. For poultry producers, ATLE now has a scientific rationale as a natural feed additive that combines antioxidant action with microenvironment regulation. For researchers, the study provides a template for evaluating how phytochemical cocktails reshape tissue microenvironments, not merely how they quench radicals. And for anyone following the broader movement toward sustainable, plant-based interventions in animal health, the purpleblow maple has just earned a prominent place on the list of plants worth watching.
The choice of tBHP as the oxidative challenge deserves note. Unlike chronic stressors such as heat or high stocking density, this organic peroxide generates intracellular free radicals directly and predictably, allowing researchers to isolate the biochemical cascade from the many confounders of real-world husbandry. That precision explains why the model is a workhorse in poultry reproductive studies, even though the damage it inflicts is more acute than what a commercial flock typically experiences.
The dual emphasis on Nrf2 and VEGF also reflects an emerging understanding that these pathways are not independent. Reactive oxygen species at moderate levels normally participate in hypoxia-inducible signaling, and when oxidative stress overwhelms that system, both antioxidant gene transcription and angiogenic factor production collapse together. A supplement that restores one axis while sparing the other would leave follicles metabolically protected but still starved of blood supply. The coordinated recovery of SOD and CAT activities alongside VEGF, ANGPT1, and HIF-1α in the supplemented hens suggests the polyphenol mixture acted upstream of both branches, a property single-molecule antioxidants often lack.
The extracellular matrix findings extend this picture beyond the vasculature. Focal adhesion and ECM-receptor interaction pathways provide the physical substrate on which granulosa cells and endothelial cells migrate during follicle growth, and their disruption by stress, followed by restoration of fibronectin, collagen, and the VEGF receptor KDR, indicates repair of tissue architecture rather than mere biochemical correction. For feed manufacturers, the practical implication is that a standardized leaf extract could be formulated into layer diets during vulnerable periods, such as the peak-to-post-peak transition, when oxidative burdens on the ovary are greatest. For comparative biologists, the study adds to evidence that ovarian microvascular integrity is a conserved determinant of fertility, making the laying hen a useful model for nutritional approaches to reproductive resilience in mammals as well.
Subject of Research: Use of Acer truncatum leaf extract as a dietary feed additive to protect laying hen ovarian function from oxidative stress via Nrf2-mediated antioxidant defense and VEGF-mediated angiogenesis.
Article Title: Dietary supplementation of Acer truncatum leaf extract alleviates oxidative-stress induced impairment of ovarian function in laying hens via Nrf2-mediated antioxidant defense and VEGF-mediated angiogenesis
Article References: Qin, K., Ma, J., Gao, M., Liu, Y., & Yang, X. (2026). Dietary supplementation of Acer truncatum leaf extract alleviates oxidative-stress induced impairment of ovarian function in laying hens via Nrf2-mediated antioxidant defense and VEGF-mediated angiogenesis. Stress Biology, 6(1), Article 60. https://doi.org/10.1007/s44154-026-00329-x
Image Credits: AI Generated
DOI: 10.1007/s44154-026-00329-x
Keywords: Acer truncatum leaf extract, laying hens, oxidative stress, Nrf2 pathway, angiogenesis, VEGF, ovarian function, poultry nutrition, reproductive hormones, extracellular matrix remodeling, feed additives, transcriptomics
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Drew Townsend. (September 3, 2026). Maple Leaf Extract Shields Egg Production From Oxidative Stress. Scienmag. https://scienmag.com/maple-leaf-extract-shields-egg-production-from-oxidative-stress/
Drew Townsend. “Maple Leaf Extract Shields Egg Production From Oxidative Stress.” Scienmag, 3 September 2026, https://scienmag.com/maple-leaf-extract-shields-egg-production-from-oxidative-stress/. Accessed 3 September 2026.
Drew Townsend. “Maple Leaf Extract Shields Egg Production From Oxidative Stress.” Scienmag. September 3, 2026. https://scienmag.com/maple-leaf-extract-shields-egg-production-from-oxidative-stress/
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