Catfish sleeve syndrome is common after winter culture and is high in March to May. In 2017, there were a large number of deaths of artificially farmed spotted forktail catfish in Sichuan Province, Hubei Province and Jiangsu Province, especially in individual breeding ponds in Dafeng City, Jiangsu Province, where the average number of dead fish per day even exceeded 10,000 catties.
On March 6 this year, the first case of spotted fork-tail catfish intestinal syndrome has appeared in the Leshan area of Sichuan Province: the farmer's 25-acre pond stocking 60,000 catties, on February 26 began to appear sick and dead, the initial death of 2-3 fish, from 28 to March 2 daily loss of fish to more than a dozen fish, from March 3 to March 6 loss of fish increased to more than 60 catties (about 100 fish), the overall trend of fish loss increased; as of March 11, the pond daily loss of fish about 1500 pounds, since March 13, the daily loss of fish has reached tens of thousands of catties The diseased fish in the pond have been closed and cannot be administered.
As temperatures rose in mid-to-early March, the outbreak of catfish diseases in the region became more and more serious, and the epidemic situation in Leshan Jingyan and Qingping areas was urgent. According to the survey, these outbreaks of fish disease fish ponds are generally transferred to the pond last year, the beginning of the year began to appear water mold symptoms, until the beginning of March with body ulcers, intussusception as the main clinical symptoms of dead fish, with the rise in temperature, the incidence of death more serious, mortality rate is generally 30-50%. Most farmers have been using different aquatic antimicrobial and antimicrobial drugs for treatment during the onset of the disease, but the effect is not good, and the treatment cost of individual farmers for one month has even reached more than 10,000 yuan. The speed of onset is so fast that there is not enough treatment time, and the incidence and death are serious, and the adult catfish and seedlings are no exception.
<b>Spotted forktail catfish onset site</b>
The main clinical symptoms of diseased catfish are swimming edges, whirling, loss of appetite, cracking of the top of the head of some diseased fish, showing "a little red" symptoms, abnormal enlargement and bleeding of liver, spleen and kidneys, with typical intussusception symptoms, and a small amount of water mold on the body surface.
<b>Illustration Of the main clinical manifestations of diseased spotted catfish</b>
Note: A, B: multiple ulcer foci on the surface of the body (water mold); C: cracking of the top of the head; A, D: rotten fins, edema at the base of the fins; E: clear ascites in the abdominal cavity; F: snout, jaw redness, needle-tip bleeding; G-H: intussusception, intestinal wall bleeding; I: bleeding and ulceration of the mucosa of the lining of the stomach
<b>Figure shows electrophoresis of rapid diagnostic results of CCV virus PCR isolated strains and tissue samples of diseased forktail catfish</b>
We further conducted laboratory diagnosis for isolated strains and tissue samples, and the results showed that the PCR test of spotted forktail catfish virus (CCV) was negative; at the same time, through the isolation, culture and identification of pathogens in diseased fish, the same strain of pathogenic bacteria was separated from the internal organs and brain parts of the diseased catfish, and then the isolated strains were subjected to in vitro drug-sensitive screening, and the market was fed back to the market line in the first time. The incidence of the disease in the areas visited has reached the middle and late stages, and the incidence is very serious. Combined with the laboratory diagnosis results, the outbreak has been basically confirmed to be caused by the weak constitution of catfish, secondary infection of bacteria, and had to use antibiotics, but the resistance of catfish isolated disease strains varies from household to household. Therefore, combined with the results of each household's drug susceptibility, the following scheme was formulated:
Internal administration: Sensitive antimicrobials are selected for internal administration, mixed with peptide exertion and vitamin C, and used for seven days until the damage is controlled.
External consumption: Considering this survey, it is found that most diseased fish have more gill filament mucus, swelling and hyperemia, and it is recommended to use povidone iodine + benzalkonium bromide.
<b>Figure shows the results of drug-sensitive screening for diseased fish body isolation</b>
At present, under the guidance of the technical staff of Tongwei Company, some spotted forktail catfish farmers in Leshan district of Sichuan Have adopted an emergency prevention and control plan, and the prevention and control effect has been shown to a certain extent. As can be seen from the figure below, seven days after the emergency plan was applied to the three catfish ponds with serious epidemics, two of the damaged fish were significantly controlled, and one household lost fish did not continue to increase and had a certain control effect.
<b>Figure shows the trend of the application effect of emergency control schemes for each household</b>
What we often call "set of intestine disease" is a comprehensive disease of the spotted forktail catfish mainly based on intestinal diseases, and it is currently the most serious disease that harms the breeding of spotted forktail catfish. The disease has the characteristics of acute onset, morbidity, high mortality, and rapid transmission, which can easily cause a large number of deaths, and once the disease occurs, it is difficult to control with existing drugs, which will cause major losses every year. The occurrence of such deaths in captive culture of spotted catfish is not a problem that has occurred in the past year or two. In recent years, many local cultured spotted forktail catfish have experienced a large number of fish losses in such diseases. How should we reflect on this recurring phenomenon of large numbers of dead fish?
Before and after the spring equinox to the Qingming Dynasty, the weather in various places generally has a large temperature difference between day and night, the water quality is unstable, and it is easy to induce the stress of catfish; after overwintering, the catfish have relatively poor physique and weak intestinal function, and most farmers blindly increase the amount of feeding in order to let the fish reach the market specifications as soon as possible, so that the digestive burden of nutrients in the intestine in a short period of time increases too quickly, and finally causes the disorder of the intestinal function of the forktail catfish and abnormal peristalsis. These factors, combined with stress caused by drastic changes in the environment, eventually induce fork-tailed catfish incision syndrome.
It can be said that changes in climate and environment, the reduction of fish immunity, low intestinal function after wintering, stress in the breeding environment, fungal infections, secondary bacterial infections, etc., are all related to the occurrence of the disease to varying degrees.
Although the application of this emergency plan has a more obvious effect, after all, there have been a large number of fish losses after the outbreak of the epidemic, and the intervention control effect is often unsatisfactory at this time. The focus of prevention and control of such diseases should still be on prevention. Before wintering and in the early spring after wintering, how to quickly and effectively restore the physique of the spotted forktail catfish, enhance immunity and anti-stress ability is the key to improving the survival rate of the spotted forktail catfish.
Therefore, during the critical April-May period, we recommend that the majority of caregivers:
<b>[No disease].</b>
The amount of food intake in the spring is low, the temperature and water temperature gradually rise, the fish body is weak after wintering, there are a large number of pathogens in the water, and it is easy to erupt into intussusception problems, so avoid excessive feeding, and excessive feeding is one of the main reasons for inducing the disease.
Physique recovery and intestinal health care after the opening of spring: It is recommended to use Tongwei "peptide power" with tongwei other animal protection products, which is conducive to the recovery of fish's physique and intestinal function, and improves the anti-stress and anti-infection ability of catfish. Peptide power (5kg/10,000 kg of fish, 2 times/month, 7 days/time), can be fed in the opening of spring, and pay attention to the key stage of April-May;
With the temperature rise, the catfish immune function and intestinal skills are weak, choose tongwei high-quality, nutritionally balanced spotted forktail catfish special feed, should gradually and slowly restore the feeding amount, remember to blindly add feeding, so as not to cause intestinal dysfunction caused by excessive intestinal load.
After the beginning of spring, it is necessary to improve the substrate and water quality in time to avoid weather instability, and the stress hazard caused by the upward flipping of harmful substances at the bottom after the exchange of the upper and lower layers on the catfish.
<b>[Initial onset].</b>
For those who have become ill or who are in the early stages of the disease:
Antibiotics (screening according to susceptibility) + peptide exertion (8 kg/10,000 kg of fish) + vitamin C
Disinfection with water (it is recommended to use povidone iodine irritating small disinfection drugs, according to the instructions for medication only)
*If there is no susceptibility test condition, Tongwei Aquatic Animal Disease Prevention and Control Engineering Laboratory can undertake related services to the outside world*
National and local joint engineering laboratory of aquaculture animal disease prevention and control technology (<b>This article is transferred from [</b><b>Tongwei Agriculture and Animal Husbandry Information</b><b>]. If you have copyright questions, please contact</b> [email protected]<b>. </b>）