Analysis of precocious mortality of Pangasius hypophthalmus larvae (Siluriformes, Pangasiidae) during the larval rearing and propostion of appropriate treatments 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" Subagja, J. /Slembrouck, Jacques Hung, L.T. /Legendre, Marc POISSON D'EAU DOUCE PISCICULTURE LARVE MORTALITE TAUX DE SURVIE AGENT PATHOGENE BACTERIE CANNIBALISME METHODE DE LUTTE ANTIBIOTIQUE ETUDE EXPERIMENTALE OXYTETRACYCLINE Both in Indonesia and Vietnam, larval rearing of Pangasius hypophthalmus remains problematic due to variable and generally low survival rates obtained. The first week represents the most critical period for these larvae and up to now the cannibalistic behaviour was considered as the main cause of mortality. In the present study, two experiments were carried out in order to better understand the evolution and causes of mortality of P. hypophthalmus larvae from hatching up to 8 days of age and find out measures to improve survival rates. The first experiment was designed to evaluate the importance of cannibalism and differences in mortality when larvae from two different females were reared either in groups of 30 individuals or in isolated conditions (30 larvae reared separately). In both cases, the culture was carried out either with or without antibiotic. The aim of the second experiment was to test Oxytetracycline and different disinfectants (Chloramine-T, formalin and "formalin + Malachite Green Oxalate") at different dosges to prevent bacterial outbreaks in the culture. The results indicated that the survival rates of P. hypophthalmus larvae was dependant on the initial quality of larvae or eggs and that larval mortality was more a consequence of pathogenic infection than a direct effect of cannibalism. The present study demonstrated that the survival rates of larvae were systematically improved when rearing as carried out in water containing antibiotic (Oxytetracycline at a dose of 5 to 20 mg/L). Survival rates and final mean body weights of larvae as high as those obtained using antibiotic were also reached with applications of disinfectants such as Chloramine-T and formalin. The use of these disinfectants is recommended for an application in commercial P. hypophthalmus hatcheries. (Résumé d'auteur) IRD Can Tho University /Legendre, Marc (ed.) /Pariselle, Antoine (ed.) 1998 text https://www.documentation.ird.fr/hor/fdi:010020353 fdi:010020353 Subagja J., Slembrouck Jacques, Hung L.T., Legendre Marc. Analysis of precocious mortality of Pangasius hypophthalmus larvae (Siluriformes, Pangasiidae) during the larval rearing and propostion of appropriate treatments. In : Legendre Marc (ed.), Pariselle Antoine (ed.), . 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" IRD ; Can Tho University, 1998, 147-155 Characterisation, Utilisation and Maintenance of Biological Diversity for the Diversification and Sustainability of Catfish Culture in South East Asia, Can Tho (VNM), 1998/05/11-15 EN INDONESIE VIET NAM