Application Of Xiphophorus Helleri In The Research Of Aquatic Pharmaceutical Clinical Experiment

At present, the main problem existing in the clinical tests of aquaculture drug is that the stability, homogeneity and repeatability of tests are relatively lower. The key is loss of standard laboratory animals. The objective of this paper is to discuss the application foreground utilizing the pure-line swordtail fish as laboratory animals in the clinical tests of aquaculture drug.1. The virulence tests of bacteria. Swordtail fishes were able to be infected with Aerornonas hydrophila strain LY1 by means of muscle injection, intraperitioneal injection, immersion, daub on body or gill, and so on, but the muscle injection was the best means. Swordtail fish were infected with 10 strains of bacteria isolated from sensitive fishes. The results showed that the virulence of bacteria to the swordtail fishes was comparatively identical with sensitive fishes. In addition, the sensitive reaction of the high generation inbreeding swordtail fish to Aeromonas hydrophila was more identical than the prime generation, and its course of death after infection was relatively centralized. So there is much hope that the pure-line swordtail fish is regarded as the aquatic laboratory animals model of artificial infection to examine virulence of bacteria instead of the other kind of fishes.2. The acute toxicity tests of antibacterial. The common fish antibacterials LD₅₀ such as lactate nofusaxine powder and ulfamycine were tested in swordtail fish, crucian carp and grass carp The following results were that oral lactate nofusaxine powder 96h LD₅₀ for above tjree fishes was＞2000mg/kg and its safe dosage was 25mg/kg; oral ulfamycine 96h LD₅₀ for those was＞4000mg/kg and its safe dosage was 350mg/kg. The obnonnity or death fish did not be found during the cours of tests.3. The acute toxicity tests of Chinese herbal medicine. The acute toxicity of Chinese herbal medicine rhuhard powder was tested in swordtail fish, crucian carp, Macrobrachium rosenbergii. The rhuhard powder 96h LC₅₀ for swordtail fish was 64.56mg/L and its safety concentration was 6.64mg/L. Its 96h LC₅₀ for crucian carp was 97.72mg/L and its safety concentration was 9.77mg/L. Its 96h LC₅₀ for Macrobrachium rosenbergii was 57.54mg/L and its safety concentration was 9.06mg/L. The safety dosage of rhuhard powder was 2～4 mg/L. According to above, swordstail fish is sensitive to Chinese herbal medicine and it is able to determine the guideline of acute toxicity instead of crucian carp and Macrobrachium rosenbergii.4. The acute toxicity tests of insecticide and the pathology of bluestone toxicity. Bluestone and trichlorphon were widely applied to curing fish parasite disease, but matters often happened because of drug abuse and overcommit leading to poisoning. Swordtail fishes with different character and different generation were utilized to do acute toxicity experiments for common insecticide such as bluestone and trichlorphon and its LC₅₀ was determined, at same time zebra-fish and crucian carp acted as control animals. Bluestone and trichlorphon 96h LC₅₀ for swordtail fish respectively was 0.79mg/g and 26.Smg/g, safety usage concentration respectively was 0.456mg/g and 2.68mg/g.The sensitivity of high generation swordtail fish to above insecticide was stronger than the prime generation, and between swordtail fishes with red-eyes-red-body and red-eyes-white-body there was a little difference to insecticide sensitivity. Bluestone and trichlorphon 96h LC₅₀ for Zebra-fish respectively was 1.47mg/g and 52.50mg/g. Bluestone and trichlorphon 96h LC₅₀ for crucian carp respectively was 2.14mg/g and 58.29mg/g. Comparing to Zeb-fish and crucian carp, the swordtail fish was more sensitive to trichlorphon.The toxicity and cumulation of bluestone in swordtail fish were investigated by lentic breed with water-supplement and drug-exchange. On the 7th, 14th,21th and 28^thday tissue samples were collected and analysed by means of pathology. The results indicated that the different concentration of bluestone is able to do gradually pathologic harm to swordtail fish's gill and so on. 5. The acute toxicity tests of disinfector. Through acute toxicity experiments of se veral common aquaculture disinfectors on swordtail fishes with different character s,the sensitivity to disinfectors was compared between swordtails and zebra-fish, g oldfish,silver carp, crucian carp and so on. The results showed that the disinfectors 96h LC₅₀ for swordtail fish wasl. llmg/L, 4.52mg/L, 0.90mg/L, 5.20mg/L, 122.7mg/L, and the one for silver crucian was 0.57mg/L, 2.45mg/L, 0.62mg/L, 1.80mg/L, 57.6m g/L, that respectively was DCCNA, TCCNA, double-chain quaternary ammonium sal t complex iodin, bleaching powder, calcium oxide and so on. It was found that sw ordtail fish to above drug was similar to the control fishes,. So swordtail fish can be used as laboratory animals to evaluate the safety of aquaculture drug.6. The prevention and cure tests of drug. The experimental fishes were infected using muscle injection and immersion by Aeromonas hydrophila strain BK-10(serum 05). Crucian carp and grass carp being as control animals, the protection experiments in swordtail fish were done by oral drug administration or immersion bath with lactate nofusaxine powder, povidone-iodine and benzalkonlum bromide solution as well as compound bi-rhuhard powder respectively belonging to antibacterial, insecticide and Chinese herbal medicine. The experimental fishes were divided into four groups, respectively the prevention group(giving drug before infecting:involving two times dosage group,usage dose group and 0.5 times dosage group), the cure group(giving drug after infecting:groups were the same as the above),the negative control group(giving no drug after infecting),the blank control group(neither giving drug nor infecting). The protective ratio was gotten through three parallel repeat experiments and each experimental group contained 40 fishes.The prevention and cure tests of lactate nofusaxine powder.The experimental fishes were infected with Ah by muscle injection,and the oral dosage of lactate nofusaxine powder was 25mg/g.The average protective ratio of the prevention group to swordtail fish and crucian was 74% and 73% and the cure one was 67% and 65%,respectively.There was a notable difference by way of the X² analysis.The prevention and cure tests of insecticide. The experimental fishes infected with Ah by immersion were prevented and cured by immersion bath of povidone-iodine and benzalkonium bromide solution. The average protective ratio of the prevention group with povidone-iodine to swordtail fish and crucian carp was 74% and 77% and the cure one was 64% and 70%, respectively.With benzalkonium bromide solution,the average protective ratio of the prevention group to them was 64% and 70% and the cure one was 62% and 65%,respectively.Compared with crucian and grass carp,the individual difference of sensitivity of swordtail to pathogeny was smaller, and the course of death was relatively centralized after infection,moreover the repeat and comparison of experimental results were better. For three parallel groups of crucian carp the data was more inordinate and the difference of data among each group was larger.The prevention and cure tests of compound bi-rhuhard powder.The experimental fishes were infected with Ah by muscle injection,and the oral dosage of compound bi-rhuhard powder was 2g/kg.The average protective ratio of the prevention group to swordtails and grass carp was 62% and 66% and the cure one was 56% and 66%,respectively.7. The test of drug residue.The nofusaxine residue was tested in crucian carp and the 18th RR-B inbreed generation swordtail fish.On the 4th and 9th day after oral 25mg/lkg nofusaxine,residue in the swordtail fish tissues were determined,in the muscle respectively was 0.465μg/g,0.049μg/g and in the liver respectively was 0.514μg/g,0.039μg/g.In the same way, the residue in thecrucian carp muscle respectively was 0.434μg/g,0.018μg/g and in the liver was0.483μg/g,0.036μg/g.On the 15th day,there was no nofusaxine residue inthe muscles and livers of swordtail fish and crucian carp.Nofusaxine residuequantity in swordtail fish was similar to crucian carp,so swordtail fish can be used as the laboratory animals modle of aquaculture drug residue.