Dietary aflatoxin impairs flesh quality through reducing nutritional value and changing myofiber characteristics in yellow catfish (Pelteobagrus fulvidraco)

Abstract Dietary contamination of aflatoxin is commonly detected in aquafeeds, and its adverse effects on growth and health of farmed fish have been frequently reported. However, the effects of dietary aflatoxin on flesh quality in fish has not been well demonstrated. To evaluate these effects, in the present study, 360 yellow catfish (25 g ± 0.05 g) were randomly divided into three groups and fed with the diets containing different concentration of aflatoxin B1(AFB1) (Control diet; AFB44 diet: 44 μg/kg; AFB234 diet: 234 μg/kg) for 8 weeks. The results showed that the dietary AFB1 exposure didn’t significantly change fish growth, organ weights, fatty acid and amino acid composition, and AFB1 residues in muscle. However, the dietary AFB1 exposure with 234 μg/kg significantly increased the total lipid and triglycerides (TG) contents in muscle, while decreased flesh contents of moisture, total protein and phospholipids (PL), and reduced myofiber diameter. Moreover, the reduced myofiber number and increased connective tissue ratio were observed in the both AFB groups. The expressions of the genes related to myofibers structural proteins were reduced with the increase of dietary AFB1 concentration. Taken together, the present results demonstrated that the 8-week dietary exposure of AFB1 with 44 or 234 μg/kg in yellow catfish would not inhibit growth or cause high AFB1 residues in flesh, but could reduce the protein content and PL/TG ratio in flesh, and significantly change the characteristics of myofibers, thereby impaired the nutritional value, flavor and sensory quality of fish flesh.