Effects of the water-soluble fraction of diesel oil on the sera biochemical indicators, histological changes, and immune responses of black rockfish Sebastes schlegelii.

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-1ß, 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.

Comparative study of peripheral blood cells in two marine fishes (Synechogobius hasta and Sebastes schlegelii): Morphological and cytochemical characterization.

The morphology, cell size and relative number of peripheral blood cells in two teleosts, Synechogobius hasta and Sebastes schlegelii, were compared using different staining methods. The results showed significant differences in cell size. The percentage of monocytes in S. hasta was greater than that in S. schlegelii (P < 0.01); however, the opposite results were obtained in the percentage of lymphocytes and thrombocytes. The two fishes shared common cytochemical-staining results, which showed that both erythrocytes were negative for all cytochemical staining; monocytes were strongly positive for PAS and positive for SBB and NAE; lymphocytes were negative for SBB, POX and NAE; neutrophils were positive for SBB and NAE; and thrombocytes were negative for SBB, ALP, POX and NAE. However, species specificity existed in the cytochemical properties. For S. hasta, monocytes were strongly positive for ALP and ACP; lymphocytes were strongly positive for ALP and weakly positive for ACP; neutrophils were strongly positive for ACP and POX; and thrombocytes were weakly positive for PAS and positive for ACP. Unlike S. hasta, monocytes were strongly positive for ACP and positive for ALP in S. schlegelii; lymphocytes were positive for ALP and partially positive for PAS; neutrophils were positive for ACP and POX; and thrombocytes were negative for PAS and ACP. The POX activity of monocytes in S. hasta was greater than that in S. schlegelii (P < 0.05), while the POX activity of neutrophils and the NAE activity of monocytes in S. hasta were significantly greater than those in S. schlegelii (P < 0.01). The results of this study can be used as a reference for the construction of haematological parameters in S. hasta and S. schlegelii for the assessment of fish health and can provide a research basis for fish diseases and immunity.