The effect of NovaSil dietary supplementation on the growth and health performance of Nile tilapia (Oreochromis niloticus) fed aflatoxin-B1 contaminated feed

The objective of this study was to evaluate the ability of NovaSil (NS) clay to sorb and mitigate the toxic effects of aflatoxin B1 (AFB1) in Nile tilapia (Oreochromis niloticus). Growth performance, targeted innate immunological function, intestinal microbial community and histology were evaluated after feeding tilapia diets with or without AFB1 and/or NS for 10 weeks. Aflatoxin B1 at concentrations of 1.5 and 3.0 ppm significantly (P < 0.05) decreased weight gain, feed efficiency, hepatosomatic index and macrophage extracellular superoxide anion production in tilapia, regardless of NS addition to the diet. The overall results regarding the efficacy of NS were mixed; however, there was a trend (P = 0.157) towards AFB1-toxicity prevention in regards to macrophage extracellular superoxide anion production. Additionally, when 0.5 and 1% NS was included in diets containing 1.5 ppm AFB1, total histopathological score was lowered; however, this protective effect was not evident when fish were exposed to 3.0 ppm AFB1. Denaturing gradient gel electrophoresis was performed to assess the effects of both AFB1 and NS on gut microbiota, but no significant differences were found among treatment groups.

► Biological effects of Aflatoxin B1 were examined in Nile tilapia.
► The efficacy of NovaSil, a montmorillonite clay, was assessed as an aflatoxin binder.
► Aflatoxin B1 at 1.5 and 3.0 ppm negatively impacted tilapia over 10 weeks.
► NovaSil provided a degree of protection, but was not as efficacious as hypothesized.