一株海水来源的弧菌拮抗菌的筛选、应用以及抑菌机制初探OA北大核心

Biological antagonism is an effective,environmentally friendly,and sustainable method for the preven-tion and treatment of Vibrio parahaemolyticus(VpAHPND)infection,which causes acute hepatopancreatic necrosis disease in Litopenaeus vannamei.This study collected samples from seawater used for the industrial aquaculture of shrimp in Dongying City,Shandong,China.The target strains were screened using plate confrontation and drilling methods and were identified using 16SrDNA and gyrB-ropD gene sequence alignment.The target strain's ability to antagonize VpAHPND was evaluated using the drilling method,and the mechanism of its resistance to VpAHPND was preliminarily explored through the localization of antibacterial compounds and co-culture experiments.A soaking method was used to determine the biological safety of this strain in post-larva12 shrimp.The effect of adding this antagonistic bacterium to water on the survival rate of L.vannamei and the number of Vibrio spp.was explored through aquaculture experiments.The results showed that Pseudoalteromonas spp.strain 1125(hereafter referred to as Ps1125)had a good ability to inhibit VpAHPND,with the antibacterial effect requiring contact with live cells,in-dependent of the supernatant and dead cells.Ps1125 is safe for shrimp post-larva12,and adding it to the water dur-ing the early stage of aquaculture reduced the number of Vibrio spp.in the aquaculture water and shrimp hepato-pancreas.The number of Vibrio spp.in the shrimp hepatopancreas was markedly reduced in the early stage of the challenge,whereas a significant increase in the shrimp survival rate was observed in the later stage.Results show that Ps1125 from marine sources inhibits antibacterial activity through live cell contact.When added to aquaculture water,the number of Vibrio spp.in the shrimp hepatopancreas and Vibrio spp.in the water can be suppressed.Thus,Ps1125 has excellent application prospects for the biological control of V.parahaemolyticus in L.vannamei.