一对虾养殖场的多病原跟踪

Tracking of Shrimp Multiple Pathogens in a Shrimp Farm

本研究通过对一对虾养殖场定期采样,采用分子生物学鉴定方法,分别对对虾体内及水环境中弧菌(Vibrio sp.)、虾肝肠胞虫(Enterocytozoon hepatopenaei, EHP)及主要病毒性病原进行了跟踪检测,同时,检测了水环境中的氨氮及亚硝基氮含量的变化趋势。结果显示,该对虾养殖场中存在的主要病原为多种致病弧菌和EHP,未检测出对虾白斑综合征病毒(WSSV)、传染性肌肉坏死病毒(IMNV)、偷死野田村病毒(CMNV)及传染性皮下和造血组织坏死病毒(IHHNV);该养殖场中弧菌检出种类达到16种,其中,主要的弧菌种类有副溶血弧菌(Vibrio parahaemolyticus)、溶藻弧菌(V.alginolyticus)、欧文氏弧菌(V.owensii)、创伤弧菌(V.vulnificus)、哈维氏弧菌(V.harveyi),且存在导致急性肝胰腺坏死病的副溶血弧菌(VPAHPND);养殖中期大棚养殖池水体氨氮及亚硝氮浓度分别达到(3.5±2.0)、(8.2±0.7) mg/L,显著高于室外养殖池水体氨氮及亚硝基氮浓度(P<0.05)。养殖期跟踪的7个虾池中,出现严重对虾病害的大棚养殖池比例达到100%,而室外养殖池仅出现轻度对虾病害,发病池比例为25%。根据研究结果推测,造成大棚养殖池对虾发病死亡的主要原因为养殖对虾感染弧菌及虾肝肠胞虫,同时,养殖密度大、水体氨氮及亚硝基氮浓度过高等在对虾病害发生中起到了协同作用。本研究结果可为当前对虾养殖病害防控技术提供理论支持和科学依据。

In order to clarify the shrimp disease occurred currently in the shrimp farms, shrimp pathogens including vibrio, Enterocytozoon hepatopenaei (EHP) and four viral pathogens(WSSV、 IMNV、CMNV and IHHNV) were detected using molecular biological detect methods under a regular sampling pattern, meanwhile the concentration of ammonia nitrogen and nitrogenous nitrogen in water body were also detected. The results showed that the main pathogens in the shrimp farm comprised various pathogenic vibrio and EHP. However the shrimp virus WSSV、IMNV、CMNV and IHHNV were not detected. The vibrio species isolated and identified reached 16 totally, and the main species were Vibrio parahaemolyticus, V. alginolyticus, V. owensii, V. vulnificus, V. harveyi. Furthermore the V. parahaemolyticus that could cause acute hepatopancreatic necrosis disease (VAHPND) was found out. The concentration of ammonia nitrogen and nitrate nitrogen in the indoor pond reaching (3.5±2.0) mg/L and (8.2±0.7) mg/L, were significantly higher than that in the outdoor pond respectively (P < 0.05) in the medium-term (July 24) of crop cycle. The intensity of infection of VAHPND and EHP show a growing trend in the culture period. In the seven ponds monitored, the ponds indoor had a higher incidence rate (100%), while the ponds outdoor had a lower incidence rate (25%). The results indicated that shrimp disease onset in the pond indoor might be caused by the infection of various vibrio and EHP, also the higher stocking density, higher concentration of the ammonia nitrogen and nitrate nitrogen in the water body played a synergy role in outbreak of shrimp disease. The results of this study could provide theoretical support and scientific data for the prevention and control of shrimp diseases.