The probiotic yeast Debaryomyces hansenii and a characterized essential oil from Mexican oregano Lippia graveolens (OEO) were assayed, separately or in combination, as feed additives in Longfin yellowtail Seriola rivoliana. Effects on skin mucosal immunity and gene expression were studied after a 6‐week experimental test, also carrying out routine histological examination of key organs (gut, liver and head kidney). Four diets were administered to fish: control (basal diet without additives); yeast (1.1% of live D. hansenii); OEO (0.05% of oregano essential oil); and Yeast + OEO (1.1% of live D. hansenii and 0.05% of OEO). Histological examination of key organs revealed a normal pattern from a healthy situation with any of the treatments. Skin mucosal immunity (protease, antiprotease, myeloperoxidase, lysozyme, superoxide dismutase, catalase and immunoglobulin M (IgM)) were evaluated. Furthermore, gene expression of two immune‐related genes (tumour necrosis factor alpha (TNF‐α) and piscidin) was analysed at head kidney and spleen by real‐time PCR. Interestingly, the Yeast diet produced an increase in most skin mucus immune‐related parameters—except for myeloperoxidase—and also an up‐regulation of TNF‐α expression. Meanwhile, the fish fed the Yeast + OEO and OEO diets had significantly higher values of IgM (both), lysozyme (OEO diet), antiprotease, myeloperoxidase and superoxide dismutase (Yeast + OEO diet), and both down‐regulated TNF‐α expression in spleen. Based on our results, D. hansenii and Mexican oregano essential oil, to a lesser extent, can improve the humoral immunity of skin mucus of Longfin yellowtail juveniles. Nevertheless, the combination of both has no synergistic effect.

中文翻译：

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汉逊德巴利酵母和牛至精油对龙尾黄tailSeriola rivoliana皮肤黏液体液免疫的调节作用

益生菌酵母汉逊酵母（Debaryomyces hansenii）和来自墨西哥牛至的Lippiagravolens（OEO）的特征性香精油分别作为饲料添加剂或在Longfin黄尾S Seriola rivoliana中进行了测定。经过6周的实验测试，研究了对皮肤黏膜免疫力和基因表达的影响，还对关键器官（肠，肝和头肾）进行了常规组织学检查。对鱼类采用四种饮食：对照（无添加剂的基础饮食）；酵母菌（占汉逊D. hansenii的1.1％）; OEO（0.05％的牛至精油）；和酵母+ OEO（占汉逊D. hansenii的1.1％和0.05％的OEO）。关键器官的组织学检查显示，任何一种治疗方法均能使健康状况正常。评估了皮肤粘膜免疫力（蛋白酶，抗蛋白酶，髓过氧化物酶，溶菌酶，超氧化物歧化酶，过氧化氢酶和免疫球蛋白M（IgM））。此外，通过实时PCR分析了两个免疫相关基因（肿瘤坏死因子α（TNF-α）和piscidin）在头部肾脏和脾脏的基因表达。有趣的是，酵母饮食能增加大多数皮肤粘液免疫相关参数（除髓过氧化物酶外），并能上调TNF-α的表达。同时，饲喂酵母+ OEO和OEO日粮的鱼的IgM（均），溶菌酶（OEO日粮），抗蛋白酶，髓过氧化物酶和超氧化物歧化酶（酵母+ OEO日粮）的值明显较高，并且都下调了脾脏中TNF-α的表达。根据我们的结果，D. hansenii和墨西哥牛至精油在较小程度上可以改善Longfin黄尾鱼幼鱼皮肤粘液的体液免疫力。但是，两者的组合没有协同作用。