The biological diversity and aquaculture of clariid and pangasiid catfishes in South-East Asia : proceedings of the mid-term workshop of the "Catfish Asia project"

One of the main problems that has to be faced by #Pangasius hypophthalmus$ breeders is the high mortality of the larvae, which can be a consequence of both cannibalism and bacterial diseases. The aim of this study was to explore the possible sources of #Aeromonas hydrophila$ that may result in an infection of #Pangasius hypophthalmus$ larvae. Isolation of bacteria was made from water source, #Artemia$ culture medium, #Artemia$ nauplii used as feed, ova (unfertilised eggs), sperm, and fed as well as unfed larvae that were collected every day from hatching, up to the age of 7 days. Characterisation of bacteria was done on the basis of morphological, physical and biochemical characteristics. The serological method of identification using polyclonal #Aeromonas hydrophila$ antiserum was used. The results indicated an absence of bacteria from sperm. By contrast, bacteria #Alcaligenes$ sp. were isolated from source of water, unfertilised eggs and from 1-day-old larvae. #Proteus$ sp. were isolated from the 1st day of age in fed larvae and from the 7th day in unfed larvae. #Aeromonas hydrophila$ were isolated from larvae of 2 days of age, and #Aeromonas punctata$ from 2-days-old unfed larvae, meanwhile #Plesiomonas shigelloides$ were identified from fed larvae of 2 and 4 days of age, and from 2-days-old unfed larvae. (Résumé d'auteur