变色拟青霉(丝状真菌),由于其高营养价值,是鱼饲料中一种有前途的新型蛋白质来源。此外,变形杆菌具有微生物相关分子模式(MAMPs),如葡聚糖和核酸,可以调节宿主的免疫反应。为了了解这种真菌在大西洋鲑鱼(Salmosalar)中的潜在生物活性,我们的研究是为了评估免疫相关生物标志物的基因表达(例如,细胞因子,效应分子和受体)在暴露于紫外线灭活的鲑鱼头肾(HLL)和脾白细胞(SL)的原代培养物中,或在有或没有灭活的粘菌(沙门氏菌中的皮肤病原体)的情况下,来自变形杆菌的部分。此外,研究了发酵条件和下游加工对变形杆菌物理超微结构和细胞壁葡聚糖含量的影响。结果表明,干燥对真菌细胞壁超微结构有显著影响,发酵方式的选择对变形杆菌中β-葡聚糖的数量有显著影响。此外,用变形杆菌及其部分刺激大西洋鲑鱼HKL和SL诱导与促炎相关的基因表达(tnfα,IL1β)和HKL中的抗微生物反应(cath2),而SL中的反应与促炎反应和调节反应有关(tnfα,il6和il10)。同样,单独用灭活的粘胶分枝杆菌进行刺激导致与促炎相关的基因上调(tnfα,IL1β,il6)抗菌反应(cath2),粘胶分枝杆菌的细胞内信号传导和识别(sclra,sclrb)和抑制HKL和SL中的调节反应(il10)。有趣的是,在48h时,细胞与变形杆菌和粘虫的共刺激诱导了SL中的免疫稳态(il6,tgfβ)和抗微生物反应(cath2)。因此,变形虫在大西洋鲑鱼HKL和SL中诱导免疫激活和细胞通讯,并调节SL中粘胶分枝杆菌诱导的促炎反应。一起来看,来自真菌的物理和化学表征的结果,以及关键免疫生物标志物的差异基因表达,为设计以变形虫为大西洋鲑鱼功能性新型饲料原料的饲喂试验和优化日粮提供了理论依据。
Paecilomyces variotii (a filamentous fungus), is a promising novel protein source in fish feeds due to its high nutritional value. Also, P. variotii has Microbial-Associated Molecular Patterns (MAMPs) such as glucans and nucleic acids that could modulate the host\'s immune response. To understand the potential bioactive properties of this fungus in Atlantic salmon (Salmo salar), our study was conducted to evaluate the gene expression of immune-related biomarkers (e.g., cytokines, effector molecules and receptors) on primary cultures from salmon head kidney (HKLs) and spleen leukocytes (SLs) exposed to either UV inactivated or fractions from P. variotii with or without inactivated Moritella viscosa (a skin pathogen in salmonids). Moreover, the effect of the fermentation conditions and down-stream processing on the physical ultrastructure and cell wall glucan content of P. variotii was characterized. The results showed that drying had a significant effect on the cell wall ultrastructure of the fungi and the choice of fermentation has a significant effect on the quantity of β-glucans in P. variotii. Furthermore, stimulating Atlantic salmon HKLs and SLs with P. variotii and its fractions induced gene expression related to pro-inflammatory (tnfα, il1β) and antimicrobial response (cath2) in HKLs, while response in SLs was related to both pro-inflammatory and regulatory response (tnfα, il6 and il10). Similarly, the stimulation with inactivated M. viscosa alone led to an up-regulation of genes related to pro-inflammatory (tnfα, il1β, il6) antimicrobial response (cath2), intra-cellular signalling and recognition of M. viscosa (sclra, sclrb) and a suppression of regulatory response (il10) in both HKLs and SLs. Interestingly, the co-stimulation of cells with P. variotii and M. viscosa induced immune homeostasis (il6, tgfβ) and antimicrobial response (cath2) in SLs at 48h. Thus, P. variotii induces immune activation and cellular communication in Atlantic salmon HKLs and SLs and modulates M. viscosa induced pro-inflammatory responses in SLs. Taken together, the results from physical and chemical characterization of the fungi, along with the differential gene expression of key immune biomarkers, provides a theoretical basis for designing feeding trials and optimize diets with P. variotii as a functional novel feed ingredient for Atlantic salmon.