Mandarin fish

Case 1 (Zhong Tailai)

1. Case details

Background information: 10000 fish weighing around 1 kilogram of feed for Mandarin fish in Shunde, Foshan, Guangdong Province

Case process: The feed mandarin fish in the farm died continuously, with 20-60 deaths per day. Disease samples were taken multiple times for testing, and the test results showed strong positive for spleen kidney necrosis virus nucleic acid (CT value of about 10) and negative for frog rainbow virus nucleic acid. It was confirmed that the feed mandarin fish were infected with spleen kidney necrosis virus disease.

2. Handling plan

Feed 2 packs of Zhongtailai mixed feed once a day for 5 consecutive days.

3. Effect feedback

After taking Zhongtailai orally with mixed feed, the number of deaths of mandarin fish showed a stepwise decrease until the 8th day, when the number of deaths was zero. The infectious spleen and kidney necrosis disease was effectively controlled, and the test result was negative for spleen and kidney necrosis virus nucleic acid. The farmers were very satisfied with the treatment results. Please refer to the following figure for specific data

Case 2 (Shen Tailai)

The protective test against the neurotoxic virus (NNV) in feed for mandarin fish was divided into a control group and a treatment group, with 30 fish in each group. The treatment group received oral administration of nerve necrosis virus binding protein mixed with feed for 5 consecutive days, while the control group was fed with feed without binding protein. Both groups received intramuscular injection of NNV virus.

The experimental results showed that the cumulative mortality rate of the control group fed mandarin fish was as high as 100% on the 10th day; On the 8th day, the cumulative mortality rate of the experimental group was 33.3%, and the condition was effectively controlled thereafter.

Case Three (ISKNV Oral Vaccine)

The oral vaccine for spleen and kidney necrosis virus (ISKNV) was used to protect against viral infections. There were two groups: an immune challenge group (ISKNV subunit orally immunized feed mandarin fish) and an challenge control group (same batch of feed mandarin fish not immunized with ISKNV subunit), with 30 mice in each group. Both groups were injected with ISKNV virus intramuscularly. The experimental results showed that the cumulative mortality rate of feed mandarin fish in the control group was as high as 100% on the 9th day; The cumulative mortality rate of the immune challenge group was 50% on the 12th day, and the condition was effectively controlled thereafter.

Case Four (Hongtailai)

At a joint experimental site in Foshan, Guangdong, where 30000 fish were fed with 15-20cm sized feed, the mandarin fish had just experienced an outbreak of frog rainbow virus disease, with about 300 fish dying every day. Disease samples were taken for testing, and the test results showed negative nucleic acid for spleen kidney necrosis virus and positive nucleic acid for frog rainbow virus, confirming that the feed mandarin fish had been infected with frog rainbow virus disease. Feeding feed containing frog rainbow virus binding protein for 7 consecutive days, starting from the use of binding protein, after 15 days, the death rate of the mandarin fish decreased to 6, indicating effective control of frog rainbow disease. The specific data is shown in the following figure.

Case 5 (Double RNA Virus Binding Protein)

At the Sanshui Mandarin Fish Joint Experimental Field in Foshan, Guangdong, there was a recent outbreak of double RNA virus disease in Mandarin fish, resulting in approximately 1000 deaths per day. Disease samples were taken and tested, and the test results showed strong positive nucleic acid for double RNA virus with a CT value of 23.77, confirming the infection of feed fed Mandarin fish with double RNA virus disease. Feeding feed containing double RNA virus binding protein for 7 consecutive days, starting from the use of binding protein, the number of deaths of the mandarin fish decreased to about 100 after 7 days, and the retest result was negative for double RNA virus nucleic acid. This indicates that the double RNA viral disease has been effectively controlled. The specific data is shown in the following figure.

Case Six (Zhong Tailai)

A 6.6 acre feed mandarin fish farm in Foshan City, Guangdong Province, tested positive for spleen kidney necrosis virus, leading to a sharp increase in the number of feed mandarin fish deaths. Starting from the seventh day, the farm began feeding feed supplemented with spleen kidney necrosis virus binding protein, with one meal per day for 7 days. Successfully controlled the upward trend of mortality in mandarin fish and observed a downward trend in their numbers. Subsequently, four days of supplementary feeding were conducted. By the 26th day, the number of dead fish had dropped to zero. After sampling and testing, the results showed that the nucleic acid test for splenic and renal necrosis virus was negative.