Pangasius are generally resistant to disease during the grow-out period as long as culture conditions are good. Deteriorating water quality, handling stress or low water temperatures are all likely to increase the parasitic or bacterial infections. Common diseases encountered in Pangasius culture are:
• Protozoan infestations on the skin or gills
• Bacterial infections from handling or environmental stress.
• Asafishwith no scales, Pangasius is also highly susceptible to the protozoan parasite icthyopthirius multifilus.
The following diseases occur commonly in Pangasius :
BNP(Bacillary necrosis of pangasius)
Fingerlings and juvenile fish are affected most, although fish of all ages are prone to this disease which is caused by a bacterium Edwardsiella ictaluri, that can survive for very long periods in pond water and substratum
Reason
• High stocking densities, pollutants, health problems and crowding are the main reasons for the onset of the disease. It is usually fatal, and mortality rates increase rapidly.
Symptoms
• The fish become lethargic and swim slowly at the surface of the water, and look pale with internal white spots on the liver, kidney and spleen.
Red spot disease
This disease is caused by a motile bacterium aeromonas septicaemia. This disease occurs in fingerlings during the grow-out phase.
Reason
• High stocking densities, environmental pollutants and organic mud in ponds are the causative agents. Red Spot Disease is more likely to occur when the fish are stressed, for example during handling or transportation
Symptoms
• include slow swimming, poor food intake, haemorrhages on the head, mouth and base of the fins and possible gas in the gut.
Parasite diseases
This disease is caused by Trichodina spp and Epistylis spp.
Reason
• They are prone to bacterial infections. Fluctuations in temperature due to adverse climate conditions, such as downpours of rain followed immediately by sunshine, trigger the onset of disease apart from poor water quality and high stocking densities.
Symptoms
• include lethargic swimming at the surface of the water, disorientation, lesions, fin rot, white spots on the body and difficulty in breathing.
• Thefish loses appetite, stops the feed intake and become very weak.
Prevention and treatment
The potential pathogens that cause diseases in pangasius take advantage of stress caused by Inadequate feed and a reduced oxygen level
• Goodbiosecurity practices are essential in preventing disease outbreaks
• Antibiotic agents are used widely for prevention and cure and to treat bacterial infections
• At very low water quality or very high stocking densities the fish can be infected.
• Ifantibiotic agents are not applied properly, the fish could be harmed by antibiotic residue affecting the final product quality.
• Probiotics can act as a growth promoter, increase disease resistance, enhance the immune response in fish, and improve water quality for better survival.
The spread of disease is countered by good aquaculture practices.
Blogger:
Dr. Sathish Prasad
Senior Scientist – Aquatic Animal Health
Growel Innovation Center,
RS NO.57, Chevuru Village, Sriharipuram Panchayat, Mudinepalli Mandal, Krishna District – Andhra Pradesh India – 521329
Email: [email protected]