Search

Black rockfish (Sebastes schlegelii) is a marine fish with high financial value; however, the frequent occurrence of bacterial diseases has caused a production decline and economic losses. This study found that hyperemia, hemorrhage, and ascites were common in S. schlegelii during the V. parahaemolyticus infection. Inflammation, degeneration, and necrosis in the liver could be observed. The epithelial mucosal integrity, the intestine epidermis thickness, the villus heights, and the number of mucous cells in the intestine were decreased after infection. Apparent differences in most of the hematological parameters between the two groups were observed, such as the corpuscular volume (CV) and NaCl concentrations of the beginning hemolysis were decreased remarkably (P < 0.01) after infecting with V. parahaemolyticus. However, the white blood cell count (WBC), lysozyme (LZM), malondialdehyde (MDA), K+, Cl−, and Ca2+ were increased significantly (P < 0.01) after infection. In addition, the mRNA expressions in four tissues (gills, liver, blood, spleen) of eleven immune-related genes were investigated. The results showed that C1r, C1s, and C1inh expression varied considerably among tissues. Caspase 10 expression was reduced in four tissues after infection, but MyD88, TNF receptor, TNF-α, BAFF, IL-1β, IL-8, and IL-10 showed increased expression profiles within 24 h after infection. In particular, IL-1β expression in the liver and spleen increased 123.67 and 104.94-fold at 6 hpi, respectively. Therefore, in addition to pathology, the hematological detection and gene expression profiles could be used in the evaluation of healthy status in fish, and this study provided a preliminary basis for the diagnosis of S. schlegelii infecting with V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

In order to understand the physiological and immune responses of Sebastes schlegelii to the water-soluble fraction of diesel oil (WSD), S. schlegelii were used as the experimental objects to study the effect of WSD on the sera biochemical indicators, histological changes, and immune responses. Significant differences in sera biochemical indicators were observed in S. schlegelii after WSD exposure. The alkaline phosphatase (ALP), glucose (GLU), and globulin (GLB) were reduced by 3.51-fold, 3.12- fold, and 1.58-fold, respectively; however, K+ was increased by 3.55-fold. The results of HE staining showed that interstitial congestion was observed in the liver; the secondary lamellae deformity and hyperplasia, epithelial lifting, the primary lamellae hyperplasia, and aneurism were observed in the gill. Epidermis thickness increased, and epidermal hyperplasia in the skin was shown. The length of the secondary lamellae shortened significantly after WSD exposure. The results of AB-PAS staining showed that three different types of mucous cells were observed in the gill, and a significant increase in the number of all three types of mucous cells was observed after WSD exposure (P < 0.05). In addition, the results of the relative mRNA expressions in the liver of eleven immune-related genes showed that the relative expression levels of IL-1β, IL-8, TNF receptor, BAFF, C1s, C1r, and MyD88 in the WSD group were substantially higher than those in the LPS group (P < 0.05), and the relative expression of caspase 10 was significantly lower than that in the LPS group (P < 0.05). At the same time, no significant differences were observed in the relative expression levels of IL-1, TNFα, and C1inh between the two groups (P > 0.05). This study was expected to provide essential data for health assessments of S. schlegelii and establish the foundation for the immune-related researches of S. schlegelii after WSD exposure. • WSD negatively affected the sera biochemical indices, gill and skin integrity, and immune response in S. schlegelii. • Tissue incompleteness and immune disturbance of fish exposed to WSD may allow the pathogens to more easily entry. • It is necessary to accurately interpret the effects of WSD on the immune system of fish. [ABSTRACT FROM AUTHOR]