The Effect of Aflatoxin-B1 on Red Drum (Sciaenops ocellatus) and Assessment of Dietary Supplementation of NovaSil for the Prevention of Aflatoxicosis

Aflatoxin B-1 (AFB(1)) is a potent carcinogen that causes growth stunting, immunosuppression and liver cancer in multiple species. The recent trend of replacing fishmeal with plant-based proteins in fish feed has amplified the AFB(1) exposure risk in farm-raised fish. NovaSil (NS), a calcium montmorillonite clay, has previously been shown to reduce AFB(1) bioavailability safely and efficaciously in several mammalian species. This study was designed to: (1) evaluate AFB(1) impact on cultured red drum, Sciaenops ocellatus, over the course of seven weeks; and (2) assess NS supplementation as a strategy to prevent aflatoxicosis. Fish were fed diets containing 0, 0.1, 0.25, 0.5, 1, 2, 3, or 5 ppm AFB(1). Two additional treatment groups were fed either 5 ppm AFB(1) + 1% NS or 5 ppm AFB(1) + 2% NS. Aflatoxin B-1 negatively impacted red drum weight gain, survival, feed efficiency, serum lysozyme concentration, hepatosomatic index (HSI), whole-body lipid levels, liver histopathological scoring, as well as trypsin inhibition. NovaSil inclusion in AFB(1)-contaminated diets improved weight gain, feed efficiency, serum lysozyme concentration, muscle somatic index, and intraperitoneal fat ratios compared to AFB(1)-treated fish. Although not significant, NS reduced AFB(1)-induced histopathological changes in the liver and decreased Proliferating Cell Nuclear Antigen (PCNA) staining. Importantly, NS supplementation improved overall health of AFB(1)-exposed red drum.