Abstract Several investigations have investigated the gut microbiota in shellfish species, but less information is available on the favorable gut bacteria colonizing the GI tract, the lactic acid bacteria (LAB), and these studies have revealed the presence of Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, Streptococcus, Vagococcus, and Weissella. Identification of LAB in shellfish digestive tract are equally distributed between culture methods and culture-independent techniques. In the majority of the studies, the LAB are identified from the whole intestine or intestinal contents, while less studies have evaluated the autochthonous LAB. Some LAB isolated from shellfish are able to produce antibacterial substances towards different potential fish pathogenic bacteria. They also play an important role in improving the feed utilization and act as effective growth promoters in shellfish, and increase diseases resistance of shellfish culture against infectious bacteria and virus. In addition, enhancement of rearing water quality and increase the resistance against stressful condition have been recorded in shellfish fed LAB diets. LAB effects on the shellfish innate immune system are mostly studied in shrimp. In addition to LAB species studied in finfish or mammal systems, autochthonous strains of LAB are also used for studies. Generally, LAB-treated shellfish (crustaceans, mollusk, and Echinodermata) significantly improve innate immune parameters and display an increased survival rate from pathogen infections. Some of the studies indicate that the treatment of LAB mixture shows better immunomodulatory effects than that of a single strain of LAB. Studies of the underlying mechanisms of shellfish innate immune regulation are required for the identification of species-specific probiotics and the correct assessment of immunological effects. The present review paper focuses on recent findings in the field of isolation and detection of LAB in the GI tract of shellfish, some information on their presence in hepatopancreas and in muscle, their administration as probiotic, their mode of action, and their interaction with shellfish immune responses.

中文翻译：

---

贝类中的乳酸菌：可能性和挑战

摘要 几项调查研究了贝类物种的肠道微生物群，但关于在胃肠道定植的有益肠道细菌乳酸菌 (LAB) 的信息较少，这些研究表明存在肉芽孢杆菌、肠球菌、乳杆菌、乳球菌。 、明串珠菌、片球菌、链球菌、迷走球菌和韦氏菌。贝类消化道中 LAB 的鉴定在培养方法和独立培养技术之间平均分布。在大多数研究中，LAB 是从整个肠道或肠道内容物中识别出来的，而很少有研究评估了本土 LAB。从贝类中分离出的一些乳酸菌能够对不同的潜在鱼类致病菌产生抗菌物质。它们在提高饲料利用率方面也发挥着重要作用，是贝类的有效生长促进剂，提高了贝类养殖对传染性细菌和病毒的抗病能力。此外，在贝类喂养的 LAB 日粮中，已经记录了养殖水质的提高和对压力条件的抵抗力的增强。LAB 对贝类先天免疫系统的影响主要在虾中进行研究。除了在有鳍鱼或哺乳动物系统中研究的 LAB 物种外，本地的 LAB 菌株也用于研究。一般而言，经 LAB 处理的贝类（甲壳类、软体动物和棘皮动物）可显着改善先天免疫参数，并显示出更高的病原体感染存活率。一些研究表明，LAB 混合物的处理显示出比单一菌株 LAB 更好的免疫调节作用。贝类先天免疫调节的潜在机制需要对物种特异性益生菌的鉴定和免疫效应的正确评估进行研究。本综述论文侧重于贝类胃肠道中 LAB 的分离和检测领域的最新发现、有关它们在肝胰腺和肌肉中的存在、它们作为益生菌的给药、它们的作用方式以及它们与贝类的相互作用的一些信息免疫反应。贝类先天免疫调节的潜在机制需要对物种特异性益生菌的鉴定和免疫效应的正确评估进行研究。本综述论文侧重于贝类胃肠道中 LAB 的分离和检测领域的最新发现、有关它们在肝胰腺和肌肉中的存在、它们作为益生菌的给药、它们的作用方式以及它们与贝类的相互作用的一些信息免疫反应。贝类先天免疫调节的潜在机制需要对物种特异性益生菌的鉴定和免疫效应的正确评估进行研究。本综述论文侧重于贝类胃肠道中 LAB 的分离和检测领域的最新发现、有关它们在肝胰腺和肌肉中的存在、它们作为益生菌的给药、它们的作用方式以及它们与贝类的相互作用的一些信息免疫反应。