摘要:
蓝藻虽然能产生有毒的生物毒素,但是也含有较高的蛋白质。为探索蓝藻饲料化利用的可能性,本文通过腹腔注射的方式研究了微囊藻毒素-LR (MC-LR)对崇仁麻鸡的半数致死剂量(LD50)及其对肝脏的氧化损伤。实验设计了4个剂量组(对照组、5、10和20 μg·kg-1 MC-LR),并在1、3、12、24和48 h检测了谷胱甘肽(GSH)含量以及谷胱甘肽S-转移酶(GST)、谷胱甘肽过氧化物酶(GPX)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性变化。结果表明,MC-LR对崇仁麻鸡的LD50值为34.67 μg·kg-1体重(bw),95%的置信限为33.51~35.83 μg·kg-1 bw。在MC-LR的作用下,鸡肝出现了氧化应激现象。3个染毒组鸡肝中GSH含量呈现先下降而后上升恢复至正常水平的趋势,GST酶活力表现为先上升而后下降至正常值的趋势,这说明GSH和GST共同参与了鸡肝中MC-LR的解毒;鸡肝中GPX酶活性在前3小时先保持不变(除了1 h的高剂量组),随即显著上升,这说明GPX和GSH共同参与了鸡肝中过量活性氧自由基(ROS)的清除,GPX可以作为监测MC-LR引起鸡毒性作用的生物标志物。CAT酶活力表现为先显著下降(P<0.05)而后快速上升至正常值的趋势,SOD酶在整个实验期间几乎保持稳定,这可能与SOD酶活性较高所致。
Abstract:
Cyanobacteria contains much protein, though it can produce toxic biotoxins. To explore the probability of utilizations of cyanobacteria as feed products, antioxidant stress and the median lethal dose (LD50) of microcystin-LR (MC-LR) in Chongren Chicken were examined. Chongren Chicken were injected intraperitoneally (i.p.) with pure MC-LR at doses of 0, 5, 10, and 20 μg·kg-1 bodyweight (bw), respectively. The glutathione (GSH), glutathione S-transferase (GST), glutathione peroxide (GPX), superoxide dismutase (SOD), and catalase (CAT) were tested at 1, 3, 12, 24, and 48 h after injection. The single-dose intraperitoneal LD50 value of MC-LR in Chongren Chicken was 34.67 μg·kg-1 bw (95% confidence interval is from 33.51 to 35.83 μg·kg-1 bw). Results showed that MC-LR significantly induced the oxidative stress in liver of chicken. The GSH content decreased firstly and then increased gradually to normal level in three dose groups, while the GST demonstrated a reverse trend, suggesting that GSH and GST play important roles in the detoxification of MC-LR. The GPX remained stable (excluding the highest dose group) at the initial 3 hours, followed by a significant increase after injection, indicating that the GPX and the GSH participate in eliminating excessive reactive oxygen species (ROS). The CAT decreased significantly firstly, and then increased to the normal level quickly. The SOD remained stable during the whole experimental period, which might be owing to the high basic SOD level in livers of Chongren Chicken.