不同铁水平饲养对大菱鲆(Scophthalmus maximus)生长及耐低氧能力影响的研究

铁元素作为细胞色素的重要成分参与鱼类细胞内的氧化还原供能过程,在鱼类应对低氧胁迫时发挥重要作用。以硫酸亚铁为铁源,研究不同铁水平饲养对大菱鲆(Scophthalmus maximus)生长及耐低氧能力的影响。在含铁量为463 mg/kg的基础饲料中添加0(A组)、75(B组)、150(C组)、225(D组)和300(E组)mg/kg铁离子,探究不同铁水平饲喂对大菱鲆常氧下的生长、血清生理生化指标以及抗低氧胁迫的影响。结果显示,常氧情况下,随着饲料中铁含量的增加,上述指标呈先增加后下降的趋势(P<0.05),且C、D组均为峰值显著高于A、B、E三组(P<0.05)。低氧胁迫及耐受实验结果显示,随着低氧胁迫的加剧,C、D两组抗氧化酶活性(SOD,GSH-PX)、低氧DO=(2.0±0.5) mg/L]死亡率均显著高于或低于其他三组(P<0.05)。铁作为重要的氧载体和电子传递体影响着生物体的物质代谢和能量代谢。研究表明饲料铁水平613~688mg/kg的饲养对大菱鲆生长性能、抗氧化系统的增强和提高低氧耐受能力具有促进作用,研究结果可为鱼类健康养殖和功能性饵料研制提供新数据支撑。

EFFECT OF DIFFERENT IRON LEVELS IN FEED ON GROWTH AND HYPOXIA TOLERANCE OF TURBOT SCOPHTHALMUS MAXIMUS

The juvenile turbot Scophthalmus maximus was used as the research object, and the effect of different iron levels in feed on the growth and hypoxia tolerance of S. maximus was studied. Using ferrous sulfate as the iron source, 0 (Group A), 75 (Group B), 150 (Group C), 225 (Group D) and 300 (Group E) mg/kg iron ions were added to the basal diet containing 463 mg/kg iron to investigate the effects of iron levels in feed on S. maximus growth under normoxia (WGR), in terms of serum physiological and biochemical indices (GLU, TC, TG, SOD, GSH-PX) and resistance to hypoxic stress. Results show that under normoxia, with the increase of iron content in feed, the above-mentioned indicators showed a trend of significant increase and then decrease (P<0.05), and the peak of Groups C and D were significantly higher than those of Groups A, B and E (P<0.05). The results of hypoxic stress and tolerance experiments showed that with the intensification of hypoxic stress, the antioxidant enzyme activities (SOD, GSH-PX)/hypoxicDO=(2.0±0.5) mg/L] mortality in Groups C and D were significantly higher/lower than the other three groups^'' (P<0.05). As an important oxygen carrier and electron transporter, iron participates in redox energy supply processes and affects the material and energy metabolism of living organisms. The feeding of dietary iron levels at 613~688 mg/kg promoted the growth performance, enhanced antioxidant system, and improved hypoxic tolerance of S. maximus. This study provided a data support to the development of healthy fish culture and functional baits, and a reference for future in-depth study on the regulation mechanism of fish iron metabolism to hypoxic stress.