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 B-1 (AFB(1)) 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 AFB(1) and/or NS for 10 weeks. Aflatoxin B-1 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 AFB(1)-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 AFB(1), total histopathological score was lowered; however, this protective effect was not evident when fish were exposed to 3.0 ppm AFB(1). Denaturing gradient gel electrophoresis was performed to assess the effects of both AFB(1) and NS on gut microbiota, but no significant differences were found among treatment groups. (C) 2012 Elsevier B.V. All rights reserved.