益生芽孢杆菌对草鱼肠黏膜结构的保护作用

为了研究益生菌对草鱼(Ctenopharyngodon idellus)肠道黏膜结构的保护作用, 选取健康草鱼随机分成3组: ①对照组: 口灌无菌PBS 0.2 mL/尾后第2和第4天分别口灌无菌PBS 0.1 mL/尾; ②嗜水气单胞菌组(Ah组): 口灌嗜水气单胞菌(Aeromonas hydrophila)菌液0.2 mL/尾(1.0×107 cfu/mL)后第2和第4天分别口灌无菌PBS 0.1 mL/尾; ③枯草芽孢杆菌保护组(Ah+Bs组): 口灌嗜水气单胞菌菌液0.2 mL/尾后第2和第4天分别口灌枯草芽孢杆菌(Bacillus subtilis)菌液0.1 mL/尾(1.0×107 cfu/mL); 连续7d取中肠中部, 通过检测草鱼肠黏膜形态及肠上皮细胞微丝骨架的变化, 旨在研究益生枯草芽孢杆菌对嗜水气单胞菌造成的肠黏膜结构损伤的保护作用。结果表明: Ah组病变主要表现为肠道黏膜上皮细胞变性, 坏死, 大量脱落; 固有层出血、水肿变粗; 大量炎性细胞浸润; 超微结构变化表现为紧密连接缝隙明显变宽; 微绒毛萎缩变短, 稀疏, 排列紊乱; 线粒体可见明显肿胀、嵴减少, 内质网明显扩张; 肠上皮细胞中的微丝呈绿色雾状, 微丝荧光强度逐渐减弱, 明显低于对照组。与Ah组相比, Ah+Bs组上述病变有明显改善, 肠道黏膜上皮细胞轻微脱落, 炎症和出血等症状明显减轻; 紧密连接缝隙明显变窄; 微绒毛数量多且排列较整齐; 线粒体无明显肿胀; 肠上皮细胞中的微丝荧光强度高于Ah组。结果说明益生芽孢杆菌对嗜水气单胞菌造成的肠黏膜结构损伤有一定的保护作用。

THE PROTECTIVE EFFECT OF PROBIOTIC BACILLUS ON THE INTESTINAL MUCOSAL STRUCTURE OF CTENOPHARYNGODON IDELLUS

To study the protective effect of probiotics on the intestinal mucosal structure ofC. idellus, the protective role ofBacillus subtilis on the intestinal mucosal structure damage byAeromonas hydrophila infection inC. idellus were randomly divided into three groups:① The control group: each fish was firstly orally administrated with 0.2 mL of aseptic phosphate buffer solution, and then orally administrated with 0.1 mL of aseptic Phosphate Buffer solution at day 2 and 4;② The Ah group: each fish was firstly orally administrated with 0.2 mL of isotonic saline suspension con-tainingA. hydrophila (1.0×107cfu/mL), and then orally administrated with 0.1 mL of aseptic phosphate buffer solution at day 2 and 4;③ The Ah+Bs group: each fish was firstly orally administrated with 0.2 mL of isotonic saline suspen-sion containingA. hydrophila, and then orally administrated with 0.1 mL of isotonic saline suspension containingB. subtilis (1.0×107cfu/mL) at day 2 and 4. Middle portion of midgut were collected every day for 7 days to observe intesti-nal mucous morphology and microfilament cytoskeleton of epithelial cells ofC. idellus. The results showed that the pathological characters in the Ah group mainly included degeneration, necrosis and shedding of the intestinal epithelial cells, hemorrhage, edema and thicker of the lamina propria. A large number of inflammatory cells were infiltrated and gap of TJ widened obviously. Microvilli became short, sparse and disorder. Mitochondria became obviously swollen and crest reduced, and endoplasmic reticulum expanded. Microfilament of intestinal epithelial cells appeared green va-porous, and the fluorescence intensity of microfilament gradually weakened, which were significantly lower than that in the control group. TheB. subtilis reduced damages of intestinal mucosal, including intestinal mucosa slightly shed;hemorrhage and inflammation phenomenon significantly reduced; Gap of TJ obviously narrowed; the number of mi-crovilli increased; the microvilli arranged regularly; mitochondria had no obvious swelling. The fluorescence intensity of microfilament in the Ah+Bs group was higher than that in the Ah group. The results indicated thatB. subtilis reduce the structural damage of intestinal mucosal byA. hydrophila infection.