Immunosuppressive effects of aflatoxin B-1 in Indian major carp (Labeo rohita)

Aflatoxin B-1 (AFB(1)) is a potent immunomodulator in endotherms. The exper iment was carried out to study the immunosuppressive nature of AFB(1) in on e ectothermic species of Indian major carp. Graded levels (0, 1.25, 5.00 mg /kg of body weight) of purified AFB(1) were intraperitoneally (i.p.) inject ed into rohu (Labea rohita) fingerlings weighing 30-50 g, and the fish were observed for a period of 90 days. At the end of the trial, blood samples w ere collected from the control group as well as the AFB(1) injected fish an d were screened for nitroblue tetrazolium (NBT) assay, serum total protein, albumin, globulin, albumin-globulin ratio (A:G), serum bactericidal activi ty and bacterial agglutination titre against Edwardsiella tarda. The aflato xin-treated fish revealed a reduction of total protein, globulin levels, ba cterial agglutination titre, NET and serum bactericidal activities, as well as an enhanced A:G ratio without change in albumin concentration, irrespec tive of dose levels of toxin treatment, when compared to the control group. Thus, AFB(1) proved to be immunosuppressive in rohu even at the lowest dos e (1.25 mg/kg body weight) of toxin treatment. This could be of economic si gnificance in intensive culture systems of rohu. (C) 2001 Elsevier Science Ltd. All rights reserved.