Heart rate variability as a neurophysiological biomarker of stress and welfare in olive flounder (Paralichthys olivaceus) under varying stocking densities
不同放養(yǎng)密度下比目魚壓力和福利的神經(jīng)生理學(xué)生物標(biāo)志物:心率變異性
Abstract
This study sought to evaluate the physiological stress responses of olive flounder (Paralichthys olivaceus) to varying stocking densities by analyzing heart rate and heart rate variability (HRV). All experiments were conducted in flow-through tanks under both normal- and high-density conditions. Bio-loggers were implanted in the fish to continuously monitor their heart rates and HRV over a 25-day period. The collected data were processed using the Mercury software, using only high-quality heart rate data. To evaluate HRV, the coefficient of variation (CV) was calculated, offering a standardized measure of heart rate variability. The fish in the high-density environments exhibited significantly higher heart rates and lower HRVs than those in normal-density environments. Elevated plasma cortisol levels in the high-density group (p < 0.05) further validated the stress responses indicated by heart rate and HRV. These findings suggest that high-density conditions induce significant stress in olive flounder, potentially reducing physiological adaptability and autonomic nervous system balance due to sympathetic dominance. This underscores the importance of density management in aquaculture to enhance fish welfare and highlights HRV analysis as a reliable, non-invasive tool for stress assessment.
摘要
本研究旨在通過分析心率和心率變異性（HRV）來評估橄欖鲆（Paralichthys olivaceus）在不同養(yǎng)殖密度下的生理應(yīng)激反應(yīng)。所有實(shí)驗(yàn)均在流水養(yǎng)殖箱中進(jìn)行，分別設(shè)置正常密度與高密度條件。實(shí)驗(yàn)魚體內(nèi)植入生物記錄器，持續(xù)監(jiān)測25天的心率與HRV數(shù)據(jù)。數(shù)據(jù)采用Mercury軟件處理，僅使用高質(zhì)量心率數(shù)據(jù)。為評估HRV，計算變異系數(shù)（CV）作為標(biāo)準(zhǔn)化的心率變異性指標(biāo)。高密度環(huán)境中的魚類心率顯著高于正常密度環(huán)境中的魚類，而心率變異性則顯著降低。高密度組的血漿皮質(zhì)醇水平升高（p < 0.05），進(jìn)一步證實(shí)了心率和心率變異性所反映的壓力反應(yīng)。這些結(jié)果表明，高密度條件會誘導(dǎo)橄欖鲆顯著應(yīng)激，可能導(dǎo)致因交感神經(jīng)優(yōu)勢而降低生理適應(yīng)性和自主神經(jīng)系統(tǒng)平衡。這凸顯了水產(chǎn)養(yǎng)殖中密度管理的重要性，以提升魚類福利，并強(qiáng)調(diào)心率變異性分析作為可靠、無創(chuàng)的壓力評估工具的價值。
