Effects of Light Spectrum and Intensity on Cellular Stress Responses in Baikal Whitefish and Its Hybrid Embryos: A Basis for Optimizing the Aquaculture Environment.

Abstract

The light spectrum is a key factor in aquaculture, but its effects on molecular stress responses during early fish development are unclear. This study examined how light of different wavelengths (spectra) affects embryos of Baikal whitefish and its hybrid with Yenisei hump-snout whitefish . Eggs were incubated from 35 days post-fertilization under white light (1.8 and 20 µmol m s), darkness, red (peak at 631 nm), green (peak at 507 nm) and blue (peak at 459 nm) light. We analyzed relative telomere length, telomerase activity, blood profiles, and expression of stress-related genes (, ) at key developmental stages. Notably, a significant increase in telomere length was observed throughout early development (from embryo to larva to fry), independent of the light spectrum. Red light and darkness acted as potent stressors, indicating proteotoxic stress and energy imbalance. In Baikal whitefish, this was accompanied by notable telomere shortening at the earliest stage and elongation at later stages under certain conditions, potentially mediated by increased telomerase activity, a response that may be metabolically costly. Conversely, green light was the most neutral. The effect of blue light differed between Baikal whitefish and its hybrid, with the hybrid proving more sensitive. Furthermore, high-intensity white light (20 µmol m s) also induced negative effects in the hybrid, such as increased telomere length, suggesting that excessive irradiance itself can be a stressor, independent of spectral composition. We conclude that darkness or a predominance of red light is suboptimal for incubating these whitefish, while green light provides a more favorable environment, offering a basis for optimizing aquaculture light conditions.

AI evidence extraction

Main findings

Embryos incubated under different light spectra showed a significant increase in telomere length across early development independent of spectrum. Red light and darkness were described as potent stressors (proteotoxic stress and energy imbalance), while green light was the most neutral; blue light effects differed by species, with the hybrid more sensitive. High-intensity white light (20 µmol m−2 s−1) induced negative effects in the hybrid, suggesting excessive irradiance can be a stressor independent of spectrum.

Outcomes measured

• relative telomere length
• telomerase activity
• blood profiles
• expression of stress-related genes

{
    "study_type": "animal",
    "exposure": {
        "band": null,
        "source": "light (visible spectrum)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "incubated from 35 days post-fertilization under different light conditions"
    },
    "population": "Baikal whitefish embryos and hybrids with Yenisei hump-snout whitefish",
    "sample_size": null,
    "outcomes": [
        "relative telomere length",
        "telomerase activity",
        "blood profiles",
        "expression of stress-related genes"
    ],
    "main_findings": "Embryos incubated under different light spectra showed a significant increase in telomere length across early development independent of spectrum. Red light and darkness were described as potent stressors (proteotoxic stress and energy imbalance), while green light was the most neutral; blue light effects differed by species, with the hybrid more sensitive. High-intensity white light (20 µmol m−2 s−1) induced negative effects in the hybrid, suggesting excessive irradiance can be a stressor independent of spectrum.",
    "effect_direction": "mixed",
    "limitations": [],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "aquaculture",
        "visible light",
        "light spectrum",
        "irradiance",
        "Baikal whitefish",
        "hybrid embryos",
        "telomere length",
        "telomerase activity",
        "stress response",
        "gene expression"
    ],
    "suggested_hubs": []
}

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