Dietary aflatoxin B1 and zearalenone contamination affected growth performance, intestinal and hepatopancreas gene expression profiles and histology of the intestine and gill in goldfish, Carassius auratus

Abstract

The effects of dietary aflatoxin B1 (AFB1) and/or zearalenone (ZEA) contamination on goldfish, was investigated. Total of 540 fingerlings, 6.25 ± 0.12 g, were randomly allocated to experimental groups comprised of factorial designation of different dietary AFB1 (0, 50 and 100 ppb) and ZEA (0, 500 and 1000 ppb) concentrations for 60 days. Each treatment was conducted in triplicate. Results showed dietary AFB1 and/or ZEA depressed the growth performance of fish; the highest and lowest weight gain (WG), final body weight, thermal growth coefficient (TGC) and daily growth coefficient (DGC) were observed in control group and AFB50ZEA1000, respectively (P < 0.05). Moreover, dietary AFB1 and/or ZEA significantly affected the gene expressions of Caspase 3, Cytochrome P450 (CYP) 1A1, Glutathione S-transferases (GST) and Heat shock proteins 70 (HSP70) in a dose-dependent and tissue specific manner (hepatopancreas or intestine) (P < 0.05). In the hepatopancreas, the highest relative expression of Caspase 3 (2.08 ± 0.43), CYP1A1 (2.73 ± 1.18), GST (32.86 ± 4.03) and HSP70 (7.55 ± 2.35) genes were observed in AFB100ZEA1000, AFB50ZEA0, AFB0ZEA1000 and AFB0ZEA1000 groups, respectively (P < 0.05). However, the highest relative expression of Caspase 3 (39.70 ± 10.98), CYP1A1 (966.4 ± 68.6), GST (175.8 ± 37.1) and HSP70 (1.01 ± 0.22) genes in the intestinal tissue were observed in AFB100ZEA1000, AFB0ZEA1000, AFB100ZEA500 AFB0ZEA0 groups (P < 0.05). The highest scores of the intestine tissue inflammation (4.0 ± 0.75) and necrosis (4.0 ± 0.75) were observed in AFB100ZEA500 group (P < 0.05). The results indicated the significant contribution of the intestine in metabolism/excretion of the feed-born toxins. Furthermore, the results revealed that dietary AFB1 and/or ZEA contamination could negatively affect fish performance and detoxifying genes expression profiles at concentrations even lower than those indicated in the literature as the safe feed mycotoxin thresholds.