Effects of tartrazine consumption on liver and intestine structure, antioxidant indices and intestinal microbiota in crucian carp (Carassius auratus)

Tartrazine (TZ), a synthetic food dye, is widely used in food, cosmetics and textiles to improve the sensory properties of final products. In recent years, there are reports on detecting azo dyes in the aquatic environment, so the impact of these compounds on aquatic organisms could not be ignored. In the present study, we aimed to evaluate the effects of different doses (0, 1.4, 5.5 and 10 mg/kg) of TZ consumption on health by using a teleost, crucian carp (Carassius auratus) as the experimental fish. The effects of TZ on liver and intestinal tissue structure, antioxidant properties and intestinal microbiota of crucian carp were analyzed. The results showed that the intake of 1.4 mg/kg of TZ led to the vacuolization of intestinal epithelial cells and decreased the height of intestinal villi. The intake of 5.5 mg/kg caused the rupture of intestinal villi, while the pathological phenomenon was more serious in the 10 mg/kg treatment group;It also showed that TZ consumption, even at 1.4 mg/kg resulted in hepatocyte injury, nuclear atrophy, deformation and even dissolution, and with the increase of TZ, the vacuolization of hepatocytes increased. Moreover, with the increase of TZ concentrations, the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH-Px) in serum and liver were downregulated, while the contents of MDA elevated. In addition, the intestinal contents sequencing results showed that TZ consumption also affected the community of the intestine microbiota structure of crucian carp. Compared with the control group, the number of effective OTUs, Chao1, Shannon and Simpson diversity indexes increased significantly in the treated groups. The number of some beneficial bacteria (Bacillus and Clostridium) decreased significantly, while the number of some pathogenic microorganisms (such as Bdellovibrio and Shewanella) increased markedly. The above results indicate that the addition of TZ in diet could damage the liver and intestinal tissue structure of crucian carp.