| dc.description.abstract | An experiment to determine Thai catfish's (Pangasius hypophthalmus Fowler) immunity was carried out using different levels of ascorbic acid (0. 1.000. 2.000 and 3.000 mg/kg feed). Fish of 15-20 g in weight were kept in aquaria tor 6 weeks with density of 15 fish/aquaria. Peed was given at 5-10 % of total biomass with frequency of three times a day. The blood sampling was taken every week and the challenge test with Aeromonas hydrophila (106cells/mrtr) injection intramuscular was done on the 30"" day. The result of this experiment shown that feed with ascorbic acid of 2.000 mg/kg was elevated the cellular responses such as: leucocyte total (34.850 cels/mm'). differential of leucocyte (lymphocyte: 72,2%, monocyte: 8,0%, neutrophyl: 7,8%), phagocytic index (13%) and humoral response (tttrc antibody: 0.829 serum aglutination unit), which at the same time proves high level of survival rate against the artificial injection using A. hydrophila. | en |
