What are the prevention and treatment methods for rotten foot disease in soft-shelled turtles?

Rotten foot disease in soft-shelled turtles is a turtle disease with a relatively high mortality rate in factory-style turtle farming in recent years. It not only has a long course and is difficult to cure, but even if cured, it easily leaves scars that affect its @#@136@#@ appearance. It is one of the turtle diseases that currently gives turtle farming enterprises the most headaches. Based on many years of practice combined with relevant research, the author introduces the causes and prevention and treatment methods of rotten foot disease in soft-shelled turtles for reference and application by farming units.

I. Symptoms of rotten foot disease in soft-shelled turtles

At the beginning of the disease, the sick turtle eats normally. As the disease progresses, activity decreases, reactions become sluggish, appetite declines, and it may even stop eating. The surface of the sick turtle's feet becomes ulcerated and deteriorated; in severe cases, the claws fall off, the four feet show grayish-white or pale-yellow tissue necrosis, and some have swollen four feet and lose the ability to crawl. At death, they mostly lie at the edge of the feeding platform or in the corners of the pond. Necropsy shows an enlarged liver that is grayish-white, empty intestines, and in severe cases a large amount of ascites; other organs show no abnormalities.

II. Causes of rotten foot disease

The main cause of rotten foot disease is infection by pathogenic bacteria after the body surface is damaged during activity, forming stubborn lesions. During the farming process, the parts of the turtle's body that move most frequently are the feet and the head and neck, so the chance of injury is relatively greater, such as when crawling, swimming, climbing, or grasping food. Once the epidermis is damaged in water, infection readily occurs. Because of the high frequency of activity, after medication the lesions often shrink slightly but become reinfected due to renewed damage. In particular, the capillaries and peripheral nerves of the turtle's four feet are relatively well developed, so once infection occurs it can trigger systemic symptoms, thereby affecting the turtle's appetite and making treatment difficult. Therefore, it is said that rotten foot disease is not easy to cure and deaths are not many but continuous; however, when totaled up, the losses are not small.

III. Prevention of rotten foot disease

According to the occurrence characteristics and causes of rotten foot disease, the following measures can be taken for prevention.

1. Adopt a reasonable farming model. Although there are currently many models for factory-style turtle farming in China, the relatively ideal one is still the light-transmitting shed with sand-free stacked-board sunning platform type. Its advantages are a large range for resting and activity, and it has no facilities that can damage the epidermis, such as sand or mesh bags. In particular, using a sunning platform allows the turtles to rest above water, reducing contact time with pathogens in the water and increasing the time for light exposure and sunning the back. This not only protects the skin but also promotes skin renewal, so allowing turtles sufficient time to sun their backs is the key to preventing rotten foot disease.

2. Be sure to stock with fertilized pond water during release

In the fertilized water of the turtle pond, there is not only abundant biological feed, but mainly all the facilities in the pond can be covered with a layer of smooth green biofilm, making it less likely for turtles to damage their body surface during activity.

3. In farming management, do not perform large water changes; instead, adopt the method of minor adjustments, because large water changes will disturb the turtles and cause them to cluster and pile up. Therefore, each time the water is adjusted, the amount of water changed should preferably not exceed 1/3 of the original pond water.

4. Usually, some disease-preventing Chinese medicines should be splashed irregularly, such as Chinese herbal medicines including gallnut, skullcap, notoginseng, and violet herb, splashed at a concentration of 10×10-6 in the pond water, which both saves money and is effective.

5. During the rapid growth period of the seedlings (generally between 100 g and 50 g), a certain amount of vitamin C and vitamin P should be added to the feed to promote skin contraction and renewal.

IV. Treatment

1. Remove those with severe disease, wash the lesions with dichlorine water, apply tetracycline ointment, then place them in a pond with a better environment for isolated individual rearing, and feed high-quality fresh live feed.

2. Those with milder disease should also be removed promptly, and 1% commercially available gentian violet solution should be applied to the lesions. After drying, return them to the original pond and add some antibiotics and vitamins to the feed for 6 days of feeding, which can control the staged progression of the disease.