Immunosuppressive effects of aflatoxin B1 in Indian major carp (Labeo rohita)

Aflatoxin B-1 (AFB(1)) is a potent immunomodulator in endotherms. The experiment was carried out to study the immunosuppressive nature of AFB(1) in one 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.) injected 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 were collected from the control group as well as the AFB(1) injected fish and were screened for nitroblue tetrazolium (NBT) assay, serum total protein, albumin, globulin, albumin-globulin ratio (A:G), serum bactericidal activity and bacterial agglutination titre against Edwardsiella tarda. The aflatoxin-treated fish revealed a reduction of total protein, globulin levels, bacterial agglutination titre, NET and serum bactericidal activities, as well as an enhanced A:G ratio without change in albumin concentration, irrespective 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 dose (1.25 mg/kg body weight) of toxin treatment. This could be of economic significance in intensive culture systems of rohu. (C) 2001 Elsevier Science Ltd. All rights reserved.