CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266400, China.
Fish Shellfish Immunol. 2019 Sep;92:119-124. doi: 10.1016/j.fsi.2019.06.003. Epub 2019 Jun 6.
Our previous work showed that Lactobacillus pentosus HC-2 has high antibacterial and adhesion activity, and as a probiotic could improve the nutrients and immunomodulatory effects in the Litopenaeus vannamei farming. In order to further investigate the influence of HC-2 surface protein on its probiotic effects, the immune and digestion related genes expression and enzymes activities, the colonization numbers of HC-2, and the histologic characteristics were analysis in shrimp hepatopancreas after feeding either the intact surface proteins, the probiotic treated with lithium chloride (LiCl) to remove noncovalently bound surface proteins or no probiotic for four weeks. The results showed that the immune genes expression of lysozyme, proPO, LGBP, Penaeidins-3α, crustin and C-type lectin, the immune enzymes activities of superoxide dismutase, catalase and Alkaline phosphatase, and the digestion enzymes of Trypsin, Lipase and α-Amylase were significantly higher in hepatopancreas of shrimp fed with intact HC-2 than that in shrimp fed with base diet or striped surface proteins HC-2 post feeding and challenge. In addition, the shrimp fed with intact HC-2 leads to the bacteria cells adhesion to hepatopancreas was significantly higher than that in shrimp fed with no surface proteins HC-2. Furthermore, the tissue damages of hepatopancreas caused by pathogenic vibrio were obviously observed in shrimp fed with base diet or no surface proteins HC-2, but no signs of damages were found in shrimp fed with intact HC-2. These results demonstrate that surface proteins are important components for HC-2 to execute probiotic effect that improve hepatopancreas immune response and nutrition digestion to protect shrimp against pathogen damage.
我们之前的工作表明，戊糖片球菌 HC-2 具有很高的抗菌和黏附活性，作为益生菌可以改善凡纳滨对虾养殖中的营养和免疫调节作用。为了进一步研究 HC-2 表面蛋白对其益生菌作用的影响，本研究分析了投喂完整表面蛋白、经氯化锂（LiCl）处理以去除非共价结合表面蛋白的益生菌和无益生菌 4 周后对凡纳滨对虾肝胰腺中免疫和消化相关基因表达和酶活性、HC-2 的定植数量以及组织学特征的影响。结果表明，投喂完整 HC-2 的对虾肝胰腺中溶菌酶、原卟啉氧化酶、LGBP、Penaeidins-3α、几丁质酶和 C 型凝集素的免疫基因表达、超氧化物歧化酶、过氧化氢酶和碱性磷酸酶的免疫酶活性以及胰蛋白酶、脂肪酶和α-淀粉酶的消化酶活性均显著高于投喂基础饲料或经 striped 处理的 HC-2 表面蛋白的对虾。此外，投喂完整 HC-2 的对虾导致细菌细胞黏附到肝胰腺的数量明显高于投喂无表面蛋白 HC-2 的对虾。此外，在投喂基础饲料或无表面蛋白 HC-2 的对虾中明显观察到肝胰腺组织受到致病性弧菌的损伤，但在投喂完整 HC-2 的对虾中未发现损伤迹象。这些结果表明，表面蛋白是 HC-2 发挥益生菌作用的重要组成部分，可提高肝胰腺免疫反应和营养消化，从而保护对虾免受病原体的损害。
