地衣芽孢杆菌对鲫鱼免疫功能、抗氧化能力及肠、肝组织结构的影响.

In order to study the effect of adding Bacillus licheniformis to the diet on the liver and intestinal tissue structure, antioxidant capacity and immune function of crucian carp, a total of 360 healthy crucian carp selected for the experiment, which were divided into blank control group (CK group), Bacillus licheniformis test group (DY group), Aeromonas hydrophila attack group (CKG group) and Bacillus licheniformis treatment group (DYG group), CK group and CKG group were fed with basic diet, the DY and DYG groups added Bacillus licheniformis to the basic feed. Each group had three replicates, each with 30 crucian carp. After the 6-week feeding test, the CKG group and DYG group crucian carp were challenged by intraperitoneal injection of Aeromonas hydrophila to determine the cumulative death rate within 14 days. The results showed as follows: compared with CK group, DY group significantly increased the activity of acid phosphatase (ACP) and the contents of complement 3 (C3), complement 4 (C4) and immunoglobulin M (IgM) in serum of carp (P<0.05) and the activity of alkaline phosphatase (AKP) had an increasing trend but not significant. DY group significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT) in serum and decreased the content of malondialdehyde (MDA) (P<0.05), after challenge, DYG group significantly inhibited oxidative damage and improved immune ability. Compared with the CK group, the length, width and muscular thickness of intestinal villus in DY group were significantly increased(P<0.05). After challenge, intestinal damage occurred in CKG group, intestinal villi were broken, intestinal epithelial cells were arranged disordered, striatum was arranged irregularly, and intestinal epithelial cells were vacuolated. Compared with CKG group, DYG group had less damage, striatum and epithelial cells were arranged neatly, and cell boundaries were obvious. The histological results of liver showed that there was no significant difference between the CK group and DY group. After the challenge, the liver nuclei were displaced and disordered, hepatocytes were damaged, nucleolysis occurred, vacuolation occurred, and hepatic sinus congestion occurred. Compared with CKG group, the liver cells in DYG group were better, the damage was reduced, the arrangement was gradually clear, and the vacuolation was relieved. The cumulative mortality of crucian carp in DYG group was significantly lower than CKG group(P<0.05). The addition of Bacillus licheniformis to the diet can not only effectively improve the antioxidant capacity of crucian carp serum, improve its immune function, but also increase the intestinal villus height and muscle layer thickness of crucian carp, and improve the damage of liver tissue structure. [ABSTRACT FROM AUTHOR]