The pathogenesis of red gill disease in river shrimp and its prevention and treatment methods

Red gill disease in river shrimp is a disease caused by infection with Aeromonas hydrophila that makes the gills of river shrimp turn red. Red gill disease in river shrimp has caused serious trouble for river shrimp farmers. Below we will look at what red gill disease in river shrimp is all about and how to treat it.

Pathogen of red gill disease in river shrimp

According to a report by Shen Jinyu et al. (2000), the pathogens of red gill disease in river shrimp are Aeromonas hydrophila, Gram-negative short bacilli, motile, oxidase-positive, fermentative, gas-producing, and positive for β—galactosidase, arginine dihydrolase, citrate utilization, indole test, acetoin test, gelatinase, glucose, mannitol, and sucrose, while negative for lysine, ornithine, hydrogen sulfide, urease, tryptophanase, inositol, sorbitol, melibiose, and amygdalin. When healthy river shrimp weighing 4-5 grams were injected with 0.1 mL of bacterial suspension into the third somite, with each mL containing 3×106 bacteria, and kept at a water temperature of 18-21°C, all died within 4-22 hours, and the median lethal dose was 1.68×104 - 3.95×103 bacteria per shrimp.

Epidemiology of red gill disease in river shrimp

The disease has a long epidemic period and occurs throughout the year, with a peak from August to October. The onset is chronic, and the mortality rate is generally 30%, while in severely affected farms the mortality rate can reach as high as 70%, mainly harming adult shrimp.

Symptoms of red gill disease in river shrimp

The main symptom is that the gills on both sides are red, and the red color is caused by the deposition of red pigment.

Diagnosis of red gill disease in river shrimp

(1) Make a preliminary diagnosis based on symptoms and epidemic conditions.

(2) For confirmation, testing can be carried out using the pathogenic Aeromonas hydrophila examination protocol developed and established by the College of Veterinary Medicine, Nanjing Agricultural University.

Treatment methods for red gill disease in river shrimp

(1) Externally splash disinfectants 2-3 times, preferably choosing residue-free disinfectants such as aquatic protection spirit, chlorine dioxide, and povidone-iodine.

(2) When the disease is severe, it is necessary to simultaneously administer medicated feed orally for 5-7 days. The pathogen is sensitive to norfloxacin, and it can be made into pelleted medicated feed with good stability in water and fed continuously for 5-7 days.

(3) After the disease is cured, 2 days later splash quicklime over the whole pond once to adjust the pond water to weakly alkaline, then 2 days later splash compound photosynthetic bacteria over the whole pond and mix compound photosynthetic bacteria into the feed for feeding, to accelerate the recovery of the shrimp.