1.Biotechnology Institute，Fujian Academy of Agricultural Sciences，Fuzhou 350003，China；2.Institute of Agricultural Quality Standards and Testing Technology，Fujian Academy of Agricultural Sciences，Fuzhou 350003，China；3.School of Marine Sciences，Ningbo University，Ningbo 315211，China
Abstract: To probe into effects of Panaxnotoginseng saponins (PNS) on the resistance of large yellow croaker (Larimichthyscrocea ) against Pseudomonasplecoglossicida, the inhibitory effect of PNS on P.plecoglossicida was detected in vitro, and mortality, relative pathogen load and expression level of immune related factors such as TNF-α were determined in the spleen and hind kidney of large yellow croaker weighing from 20 g to 30 g intraperitoneously injected with PNS solution before and after infection with P.plecoglossicida. On the third day post injection, the fish was infected with P.plecoglossicida at a concentration of 1.02×109 CFU/L by immersion. The results showed that PNS at a concentration of 50.00 mg/mL and 25.00 mg/mL had significant antibacterial effect in vitro (P<0.05); the survival rate of fish injected with PNS (PNS group) was 18.46% higher than that of fish injected with sterile saline solution (control group) 8 days after infection with P.plecoglossicida (P>0.05); As for the PNS group, the protein expression level of TNF-α in the spleen tissue was consistently lower than that in the control group (P<0.05), while the mRNA level was higher than that in the control group after infection (P<0.05). The finding indicated that PNS could inhibit P.plecoglossicidainvitro, injection of PNS could enhance the resistance of large yellow croaker against P.plecoglossicida, reduce bacterial load in spleen and hind kidney, regulate the expression of TNF-α, and improve the survival rate after infection.
2023, Vol. 38 
