Prevention of cytogenetic, histochemical and biochemical alterations in Oreochromis niloticus by dietary supplement of sorbent materials

The current study was conducted to evaluate the ability of Egyptian bentonite (EB) and montmorillonite (EM) for the prevention of genotoxicity, histochemical and biochemical changes induced by aflatoxin B1 (AFB1) using the micronucleus (MN) assay, chromosomal aberrations and DNA fragmentation analysis in Tilapia fish. Six groups of fish were treated for 3 weeks and included the control group, AFB1-treated group and the groups treated with EB or EM alone or in combination with AFB1. At the end of experiment period, blood samples were collected for MN, testosterone and biochemical assays. Chromosomal aberrations were determined in kidney tissues, DNA fragmentation test was determined in liver and testis, whereas histochemical study was carried out on liver, testis and gills. The results indicated that a significant decrease in total protein, albumin, globulin, testosterone and DNA content in liver, gills and testis accompanied with a significant increase in number of micronucleated erythrocytes (MnRBCs), total chromosomal aberrations in kidney and DNA fragmentation in testis and liver of fish received AFB1 alone. Fish treated with EB or EM alone were comparable to the control regarding the biochemical parameters except testosterone in EB-treated group which was significantly decreased. Both clays did not induce any significant differences in number of MnRBCs, chromosomal aberrations in the kidney, DNA fragmentation in testis, but not in liver of EB-treated group. The combined treatment with AFB1 and EB or EM succeeded to improve all the tested parameters towards the control values although it did not normalize them. Moreover, the improvement was pronounced in the group received EM plus AFB1. It could be concluded that EB and EM have the ability to tightly bind AFB1 in the gastrointestinal tract of fish resulting in decreasing its bioavailability. Moreover, the two tested clays were safe and can be used as potential aflatoxin binders in animal feed.