Evidence of oxidative stress in American kestrels exposed to electromagnetic fields.

Abstract

Exposure to electromagnetic fields (EMFs) alters melatonin, behavior, growth, and reproduction of captive American kestrels (Falco sparverius), particularly of males. EMF exposure is a "possible" human carcinogen and associated with some neurodegenerative diseases. Oxidative stress contributes to cancer, neurodegenerative diseases, and immune disorders. We tested whether EMF exposure elicits an avian immune response and alters oxidative stress levels. Captive male kestrels were bred under control or EMF conditions equivalent to those experienced by wild kestrels. Short-term EMF exposure (one breeding season) suppressed plasma total proteins, hematocrits, and carotenoids in the first half of the breeding season. It also suppressed erythrocyte cells and lymphocyte proportions, but elevated granulosa proportions at the end of the breeding season. Long-term EMF exposure (two breeding seasons) suppressed hematocrits in the first half of the reproductive period too. Results indicate that only short-term EMF birds experience an immune response, particularly during the early half of the breeding season. The elevation of granulocytes, and the suppression of carotenoids, total proteins, and previously melatonin in the same kestrels, signifies that the short-term EMF male kestrels had higher levels of oxidative stress, due to an immune response and/or EMF exposure. Long-term EMF exposure may be linked to higher levels of oxidative stress through EMF exposure only.

AI evidence extraction

Main findings

Male kestrels bred under EMF conditions showed suppressed plasma total proteins, hematocrits, and carotenoids during the first half of the breeding season under short-term exposure, along with suppressed erythrocyte cells and lymphocyte proportions and elevated granulocyte proportions at the end of the season. Long-term exposure also suppressed hematocrits in the first half of the reproductive period. The authors interpret the biomarker pattern as indicating higher oxidative stress in EMF-exposed birds, with an immune response evident mainly in short-term exposed birds.

Outcomes measured

• Plasma total proteins
• Hematocrit
• Carotenoids
• Erythrocyte cells
• Lymphocyte proportions
• Granulocyte proportions
• Immune response indicators
• Oxidative stress (inferred via immune/biomarker changes)

Limitations

• EMF characteristics (e.g., frequency, field strength, SAR) not reported in the provided abstract
• Sample size not reported in the provided abstract
• Oxidative stress not described as directly measured; interpretation is based on immune/biomarker changes

Suggested hubs

• animal-studies (0.9)
  Experimental exposure study in captive birds assessing immune/oxidative stress-related biomarkers.

{
    "study_type": "animal",
    "exposure": {
        "band": null,
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "Short-term: one breeding season; Long-term: two breeding seasons"
    },
    "population": "Captive male American kestrels (Falco sparverius)",
    "sample_size": null,
    "outcomes": [
        "Plasma total proteins",
        "Hematocrit",
        "Carotenoids",
        "Erythrocyte cells",
        "Lymphocyte proportions",
        "Granulocyte proportions",
        "Immune response indicators",
        "Oxidative stress (inferred via immune/biomarker changes)"
    ],
    "main_findings": "Male kestrels bred under EMF conditions showed suppressed plasma total proteins, hematocrits, and carotenoids during the first half of the breeding season under short-term exposure, along with suppressed erythrocyte cells and lymphocyte proportions and elevated granulocyte proportions at the end of the season. Long-term exposure also suppressed hematocrits in the first half of the reproductive period. The authors interpret the biomarker pattern as indicating higher oxidative stress in EMF-exposed birds, with an immune response evident mainly in short-term exposed birds.",
    "effect_direction": "harm",
    "limitations": [
        "EMF characteristics (e.g., frequency, field strength, SAR) not reported in the provided abstract",
        "Sample size not reported in the provided abstract",
        "Oxidative stress not described as directly measured; interpretation is based on immune/biomarker changes"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "electromagnetic fields",
        "EMF",
        "American kestrel",
        "Falco sparverius",
        "immune response",
        "oxidative stress",
        "melatonin",
        "hematocrit",
        "carotenoids",
        "granulocytes",
        "lymphocytes"
    ],
    "suggested_hubs": [
        {
            "slug": "animal-studies",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Experimental exposure study in captive birds assessing immune/oxidative stress-related biomarkers."
        }
    ]
}

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