{"id":40984,"date":"2026-02-18T00:01:47","date_gmt":"2026-02-18T05:01:47","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=40984"},"modified":"2026-02-17T12:37:25","modified_gmt":"2026-02-17T17:37:25","slug":"dietary-exposure-of-poultry-to-common-pesticide-mixtures-threatens-reproductive-health-study-finds","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2026\/02\/dietary-exposure-of-poultry-to-common-pesticide-mixtures-threatens-reproductive-health-study-finds\/","title":{"rendered":"Dietary Exposure of Poultry to Common Pesticide Mixtures Threatens Reproductive Health, Study Finds"},"content":{"rendered":"

(Beyond Pesticides<\/em>, February 18, 2026) Research finds that widespread agricultural pesticide use increases chronic dietary exposure in poultry and leads to adverse reproductive effects<\/a>, despite meeting legal residue limits. As published in Poultry Science<\/em><\/a> by researchers in Poland, the study analyzes low-dose exposure of roosters (Gallus gallus domesticus<\/em>) to the fungicide tebuconazole<\/a> (TEB), the insecticide imidacloprid<\/a> (IMI), and the weed killer glyphosate<\/a> (GLP) individually and in mixtures<\/a>, with all concentrations at or below the maximum residue limits (MRLs) established by the European Union (EU). \u201cSub-MRL pesticide exposure impaired male reproductive function, with the most pronounced effects observed following combined treatments,\u201d the authors report. They continue: \u201c[E]xposure resulted in reduced semen quality, decreased fertility and hatchability, and increased embryo mortality, particularly in groups receiving IMI alone or in combination. These functional impairments were accompanied by detectable pesticide residues in reproductive tissues and body fluids, as well as modulation [modification\/alteration] of local and systemic immune parameters.\u201d<\/p>\n

The results of the experiment highlight how combined pesticide exposure, resulting from common use of multiple pesticide active ingredients concurrently, produces \u201cstronger and more persistent reproductive effects than individual compounds, indicating mixture-specific toxicity.\u201d This study is particularly important, as it represents the chronic exposure to MRL-compliant pesticide residues in food that the researchers find are linked to compromised avian reproductive performance. \u201cThe persistence of residues in reproductive compartments and excreta further highlights potential environmental and biological risks, supporting the need to consider reproductive endpoints and chronic mixture exposure in pesticide risk assessment frameworks,\u201d the authors state.<\/p>\n

Background<\/strong><\/p>\n

As the use of pesticides in agriculture contaminates animal feed, there is a wide body of science connecting this exposure to adverse reproductive health effects in both mammals and birds. The majority of studies, however, utilize high pesticide doses. While the EU sets regulations for pesticide residues in foodstuffs, poultry feed, composed of diverse plant-based ingredients, contains many pesticide residues that can lead to adverse effects even when below established limits. (See studies here<\/a>, here<\/a>, here<\/a>, here<\/a>, and here<\/a>.)<\/p>\n

As previously covered by Beyond Pesticides in a Daily News<\/em> titled Review of Science on Glyphosate Weed Killer in Poultry Production Highlights Extraordinary Health Threats<\/a>, a scientific review in World\u2019s Poultry Science Journal<\/em><\/a> from last year highlights the adverse health effects on avian species from exposure to the widely used weed killer glyphosate (Roundup\u1d40\u1d39) throughout the process of poultry production. The herbicide enters the poultry production system through residues in genetically engineered feed. An earlier article in Scientific Reports<\/em><\/a> concludes that glyphosate\u2019s (GLP) \u201cwidespread application on feed crops leaves residues in the feed,\u201d while residues are \u201cfound to be common in conventional eggs acquired from grocery stores.\u201d<\/p>\n

In analyzing the biochemical, toxicological, and ecological impacts of glyphosate on poultry, particularly chickens, the authors find a wide body of evidence linking glyphosate and its metabolite (breakdown product) aminomethylphosphonic acid (AMPA<\/a>) to debilitating hazards. These sublethal effects include disruption of the gut microbiome and gastrointestinal disease; decreased productivity and diminished reproductive health; hepatic and kidney toxicity; growth and developmental impacts, including teratogenicity and embryotoxicity; endocrine disruption and oxidative stress; and impaired immune functions. Glyphosate residues in animal feed, as well as in water and through other exposure routes, pose risks to both animal and human health, as these residues can bioaccumulate and biomagnify<\/a> throughout the food chain.<\/p>\n

Study Methodology<\/strong><\/p>\n

In the present study, the three pesticides tebuconazole (TEB), imidacloprid (IMI), and glyphosate (GLP) are analyzed both singularly and in combination, based on \u201ctheir extensive agricultural use, environmental persistence, and increasing evidence of adverse effects on reproductive health, even at low exposure levels.\u201d TEB is a triazole fungicide known not to easily biodegrade, which leads to persistent contamination in soil, water, and food. (See studies here<\/a> and here<\/a>.) IMI is a neonicotinoid insecticide with high water solubility and environmental persistence. (See here<\/a> and here<\/a>.) Although IMI and other neonicotinoids are meant to target insect receptors, a multitude of studies<\/a> have shown their negative effects on the mammalian reproductive system. While the EU banned outdoor agricultural uses of IMI in 2018, both the compound and its metabolites (breakdown products) are \u201cfrequently detected in soil, surface water, and feed samples, underscoring its environmental persistence and the continued occurrence of limited uses or legacy contamination.\u201d The last active ingredient included in the study, GLP, is a nonselective herbicide used as a broad-spectrum weed killer and has a long history of adverse health and environmental effects. (See additional Daily News <\/em>coverage here<\/a>.)<\/p>\n

The aim of the study is \u201cto evaluate the effects of six weeks of dietary exposure to low, sublethal doses of tebuconazole, imidacloprid, and glyphosate\u2014administered individually or in combination\u201d and determine the impacts on reproductive performance in roosters. “Specifically, we assessed semen quality; fertilization and hatchability rates; embryonic mortality; and pesticide residues in the blood, semen, testicles, breast muscles, liver, and manure of roosters in vivo,\u201d the researchers note. They continue: \u201cIn addition, we analyzed immune-related tissues (cecal tonsils and the spleen) to determine whether low-dose pesticide exposure modulates mucosal and systemic immune responses in poultry. These daily intake levels were derived from analytically confirmed pesticide concentrations in feed prepared at EU MRLs, reflecting environmentally realistic exposure scenarios.\u201d<\/p>\n

The study design includes eight groups, each with ten twenty-one-week-old roosters, exposed to the active ingredients in their feed for six weeks during Phase I, followed by a four-week pesticide-free recovery period for Phase II. The authors describe the experimental setup, saying: “Group 1 served as the control without pesticide residues in their diet. Group 2 received feed with the addition of TEB, group 3 with the addition of IMI, group 4 with the addition of GLP, group 5 with the addition of TEB + IMI, group 6 with the addition of TEB + GLP, group 7 with the addition of IMI + GLP, and group 8 with the addition of TEB + IMI + GLP.\u201d This allowed for analysis of effects from each active ingredient individually and in pesticide mixtures<\/a>.<\/p>\n

Semen was collected throughout the experiment, in both phases I and II, and used to inseminate 40 hens (five females per group) to assess the \u201cactual fertility of the roosters and the fertilization capability of their sperm in vivo.\u201d Additionally, at both the six- and thirteen-week mark in the experiment, \u201cfive males from each group were euthanized, and samples of blood, tissues (testes, liver, and breast muscle), and manure were collected to assess pesticide residue levels.\u201d<\/p>\n

Results<\/strong><\/p>\n

After being fed the pesticide-supplemented diets for six weeks during Phase I, the roosters experienced several altered motility parameters, with the IMI+GLP combination group experiencing the \u201cstrongest negative effect, significantly reducing progressive motility.\u201d During this time, IMI individually reduced sperm membrane integrity and led to a significant increase in embryonic mortality, and all groups with pesticide exposure showed a lower number of live sperm cells present in the samples. The authors also report that, \u201cSix-week exposure to TEB, IMI, TEB+GLP, IMI+GLP, and TEB+IMI+GLP pesticides resulted in a significant reduction in fertility and hatchability compared with the control group.\u201d<\/p>\n

In the tissue samples, there is a significant accumulation of TEB in all examined tissues, with the highest levels detected in manure, followed by liver, breast muscle, and testes. IMI exposure \u201cresulted in significant accumulation of this pesticide in the testes, liver, blood serum, semen, and manure,\u201d while GLP \u201caccumulated significantly in all analyzed tissues, body fluids, and manure compared with the control group.\u201d For GLP, the highest concentrations occurred in manure and liver samples.<\/p>\n

Other noteworthy results include that the \u201cstrongest reproductive impairments in fertility and hatchability rates were observed in the IMI+GLP and TEB+IMI+GLP groups\u201d and that \u201cafter the interruption in pesticide exposure, the group receiving the combination of all three pesticides showed a decrease in sperm membrane integrity, indicating a persistent synergistic effect<\/a> of their combined action.\u201d All of these results indicate that exposure to low doses of pesticides in poultry feed, even within the MRLs set by the EU, can have clear adverse effects on reproductive endpoints.<\/p>\n

In summary, the researchers say: \u201cOur findings demonstrate that chronic exposure to sub-MRL levels of pesticides can compromise avian reproductive performance, as reflected by impaired sperm functionality, reduced fertilization success, altered embryo development, and decreased fertility and hatchability. Importantly, these reproductive impairments were accompanied by measurable pesticide residues in tissues and body fluids, along with alterations in peripheral immune organs… These findings further indicate that pesticide residues not only traverse the avian digestive system but also persist in excreta, thereby contributing to environmental circulation and potential long-term exposure pathways. In this context, current MRLs, largely derived from dietary risk assessments, may not fully capture risks to avian reproductive performance under chronic and combined exposures.\u201d<\/p>\n

Previous Research<\/strong><\/p>\n

Cited within the current study is additional research connecting pesticides to reproductive effects in multiple species. As the authors point out, pesticides are able to penetrate blood<\/a>, semen<\/a>, and tissues, and can lead to reproductive dysfunction<\/a>. Noteworthy study results include:<\/p>\n