Effects of dietary garlic against cadmium induced immunotoxicity in sea bass head, kidney and liver tissues: A transcriptomic approach

The knowledge about the protective effects of garlic against heavy metals on fish immunotoxicity is very limited. Juvenile sea bass specimens where maintained under three food diets (diet1: normal without garlic supply, diet 2: 2% garlic powder; diet 3: 6% garlic powder). After 30 days of specific diets, each group was injected with 500 µg.kg-1of Cd. Glutathiones-transferase activity (GST) as well as its related gene expression (gst) levels were monitored after 1 and 3 days of Cd injection in liver and head kidney tissues. Moreover, the gene expression profile of genes related to apoptosis (Bcl2 associated X protein; bax) and immune response (heavy chain of immunoglobulin M (ighm), T-cell receptor beta chain (tcrb) and interleukin-1 beta (il1b)) were investigated in both tissues. 2% garlic powder specific diet reversed the Cd-induced inhibition of GST in liver and significantly promoted the upregulation of gst in liver and head kidney. While, Cd induced a significant up-regulation of bax and a down regulation of immune related genes in the investigated tissues, garlic diet rendered a reversion of the later effects. This study provides a transcriptomic approach for elucidating the protective effects of garlic against Cd toxicity, and particularly the immunotoxicity, in fish head kidney and liver.