环境抗生素对草鱼生长、肠道健康及肌肉品质的影响

Effects of environmental antibiotics on growth, intestinal health, and muscle quality of Ctenopharyngodon idella

  • 摘要: 目的 探究环境中土霉素(OTC)、诺氟沙星(NOR)和磺胺甲恶唑(SMX)对草鱼生长、肠道健康及肌肉品质的影响,为抗生素的毒理学评价提供新思路。方法 设对照组(0 ng/L)和3个抗生素处理组SMX(1000 ng/L)、NOR(1000 ng/L)、OTC(5000 ng/L),饲养平均体质量为50.52±0.70 g的草鱼90 d,测定其生长性能、肠道和肌肉的微观结构,肠道、肌肉和血清的生化指标以及肌肉品质相关指标。结果 对草鱼进行环境OTC暴露会显著提高草鱼的饲料系数和肠道淀粉酶活性(P<0.05,下同),并引发草鱼的应激反应,但对草鱼的生长性能无明显影响。对草鱼肠道进行组织学和生化分析后发现,环境抗生素暴露增加草鱼肠道组织蛋白质羰基、活性氧(ROS)及丙二醛(MDA)含量,降低草鱼肠道组织总抗氧化能力(T-AOC)、还原型谷胱甘肽(GSH)含量及超氧化物歧化酶(SOD)活性,表明环境抗生素暴露会造成草鱼肠道抗氧化反应的发生。环境抗生素暴露增加草鱼肠道组织的白细胞介素-8(IL-8)、白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)及转化生长因子-β(TGF-β)含量;此外,SMX组闭锁蛋白(Occludin)、紧密连接蛋白1(Claudin-1)、紧密连接蛋白2(Claudin-2)含量及OTC组Claudin-1含量均显著低于对照组,表明环境抗生素暴露会造成草鱼肠道炎症反应的发生,并破坏草鱼的肠道屏障。对环境OTC和SMX暴露的草鱼肠道微观结构进行观察,发现草鱼肠道出现结构性损伤。环境OTC暴露显著降低草鱼肌肉的持水力、回复性及弹性,但环境抗生素暴露并未影响草鱼肌纤维生长。结论 环境抗生素暴露会破坏草鱼肠道健康,但不会影响草鱼的正常生长;环境OTC暴露在一定程度上降低草鱼的肌肉品质。

     

    Abstract: Objective This study aimed to investigate effects of environmental oxytetracycline (OTC), norfloxacin (NOR), and sulfamethoxazole (SMX) on the growth, intestinal health and muscle quality of Ctenopharyngodon idella, thereby providing insights for antibiotic toxicological assessment.Method A control group (0 ng/L) and three antibiotic threatment groups SMX (1000 ng/L), NOR (1000 ng/L) and OTC (5000 ng/L), were set up. Ctenopharyngodon idella with an average body mass of 50.52±0.70 g were reared for 90 d to determine their growth performance, intestinal and muscle microstructures, biochemical indexes of the intestinal tract, muscle, and serum, as well as indexes related to muscle quality.Result Exposure to environmental OTC significantly increased the feed coefficient and intestinal amylase activity (P<0.05,the same below), and triggered the stress response of Ctenopharyngodon idella, but such exposure had no significant effect on the growth performance of Ctenopharyngodon idella. Histological and biochemical analyses of Ctenopharyngodon idella intestinal tract revealed that exposure to environmental antibiotic increased the contents of protein carbonyl, reactive oxygen (ROS), and malondialdehyde (MDA) of Ctenopharyngodon idella intestinal tissues, decreased the contents of total antioxidant capacity (T-AOC) and glutathione (GSH), and reduced the activity of super-oxide dismutase (SOD), indicating that the exposure to environmental antibiotic caused the intestinal antioxidant responses in Ctenopharyngodon idella. Exposure to environmental antibiotic increased the contents of interleukin-8 (IL-8), interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α), and transforming growth factor-β (TGF-β) in the intestinal tissues of Ctenopharyngodon idella. In addition, contents of Occludin, Claudin-1, Claudin-2 in the SMX group and the Claudin-1 content in the OTC group were significantly lower than those in the control group, indicating that exposure to environmental antibiotic caused intestinal inflammatory response and disrupted the intestinal barrier of Ctenopharyngodon idella. Meanwhile, the observation of intestinal microstructure of Ctenopharyngodon idella exposed to environmental OTC and SMX revealed structural damage to the intestinal tract. In addition, the exposure to environmental OTC significantly reduced the water holding capacity, recovery, and elasticity of muscle; however, such exposure did not affect the muscle fibre growth of Ctenopharyngodon idella.Conclusion Exposure to environmental antibiotics disrupts the intestinal health of Ctenopharyngodon idella, but does not affect its normal growth; exposure to environmental OTC reduces the muscle quality of Ctenopharyngodon idella to a certain extent.

     

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