Identify And Control Methods Of Symphysodon Aequfasciatus Saprolegnia

Saprolegniasis is one of the common diseases of freshwater aquaculture.It has a wide geographical area,no selectivity to host,and a variety of infections,which can occur at 5 ?-30 ?.Many domestic and foreign experts and scholars have made some progress.However,this kind of disease is still not well resolved,it is not yet clear what kind of water is the cause of the occurrence of the disease.The observation and identification of the life history of discus fish species of fungi,and study the control method of the urgent.In view of this,this paper through the extraction with saprolegniasis discus fish roe,obtained a strain of pathogenic strain YL2,modern molecular methods and the use of traditional morphological and ITS combination of the identification results showed that the pathogenic bacteria species,discus fish mould for Saprolegnia parasitica;the control methods of inquiry,were compared using the inhibitory effect of different drugs on YL2 were found,the inhibition effect of Kathan better,and then to discuss the discus fish safety;finally through the artificial infection test to verify its antibacterial effect.The results of this study are: 1.Isolation and identification of strain YL2Take the laboratory with saprolegniasis discus fish,by the method of separation and purification,to obtain a strain of pathogenic Saprolegnia,named YL2,by now the water is the most common fungal species identification methods,namely the traditional morphological and molecular biological sequence analysis of ITS technology as a method for identification of species.Besides the common test methods,the use of the most new microbial lysate,can be directly used for detecting PCR nucleic acid release reaction,as the above extraction method of YL2 strain DNA two methods,both strain YL2 was identified as Saprolegnia parasitica,DNA after extraction compared with a more efficient way,can reach PCR for the purpose of rapid microbiological detection,the new method can be used as water extraction of fungal DNA.2.Life history of strain YL2YL2 appearance of white cottony mycelia,the lactic acid dye in Medan fixed,observed under the microscope is a tubular structure,transparent;temperature controlled water was observed by inverted microscope and its life history,at different temperatures when cultured at 25 ? when the growth is the best,most suitable for the growth of strain YL2,and the discus fish growth incubation temperature is close to that of this speculation is the main reason for discus fish infected at hatching;at 20 ?-25 ?under the condition of constant temperature,the 3d rod sporangium formation,the 4d began to release spores,release for bacteria genus of typical water mold can produce a large number of sexual organs at 15 ? under the condition of constant temperature,the 5 d has a large spherical archegonium formation,and the main body for perigonial or the same branch,is the typical morphological characteristics of saprolegnia.3.Strain YL2 Drug sensitivity CharacteristicThe use of several different types of drugs to study the effect of saprolegnia,including probiotics,disinfectants,preservatives and enzymes.Through the comparative analysis of four types of drugs for saprolegnia YL2 mycelium growth inhibition and differences in inhibitory concentration between the germination of saprolegnia spores found: Probiotics and enzymes for inhibiting the mycelial growth of the effect is not obvious,antiseptic and disinfectant class can inhibit mycelium growth,among 3 concentration group of high,medium and low in comparison,found that the inhibitory effect in four kinds of drugs: Kathan> povidone-iodine> bronopol = peracetic acid,and with the concentration increase the antibacterial ability is strengthen,the rest is the best antibacterial effect of Kathan;probiotics and enzymes for fungal spore germination in water without inhibitory effect,preservatives and disinfectants can inhibit the spore germination among them,the saprolegnia spores can inhibit of the germination of 80% in the concentration of 16mg/L,but the other drugs of povidone-iodine,bronopol and peracetic,which can inhibit the germination of 80%,with a higher concentration than high concentration of usual.Therefore,it can be concluded that the effect of Kathan on saprolegnia is better.4.Effect of kathon on the prevention and cure of Symphysodon aequfasciatusKathon is internationally recognized as a broad-spectrum preservative for daily use,and it is safe to use for a long time in a safe range.The LC50 and the safe concentration(SC)of the Kathon in Symphysodon aequfasciatus were measured,on the basis of inhibitory effect of Kathon on the saprolegnia YL2 spores and mycelium growth,to study the preventive effect of Kathon on saprolegnia of Symphysodon aequfasciatus by artificial anti infection test.Finally,it was found that the concentration of 16mg/L can effectively inhibit the growth of Saprolegnia hyphae and spore germination,so as to achieve the purpose of inhibiting Saprolegnia effect,inhibit the effect of Saprolegnia,can be used as a preventive drug of saprolegnia.