TNF-Α, IL-6, HSP-70, fish growth hormone, and growth performance of sea trout, Salmo trutta (Actinopterygii: Salmoniformes: Salmonidae) after long-term dietary administration of β-glucan and BGN-2

Abstract

The presently reported study intended to examine the effect of the oral administration of an immunomodulator β-glucan and β-glucan-containing product (BGN-2) on the levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), fish heat shock protein 70 (HSP-70), and fish growth hormone (GH) as well as growth performance of cultured sea trout juveniles. The sea trout is a migratory sea-run brown trout, Salmo trutta Linnaeus, 1758. The fish (total of 15 000) were divided into four experimental and one control group including control (consisting of basal diet) (D1); basal diet + 1 g kg–1 β-glucan (D2); basal diet + 3 g kg–1 β-glucan (D3); basal diet + 6 g kg–1BGN-2 (D4); basal diet + 14 g kg–1BGN-2 (D5). The fish fed D4 and D5 diets showed significantly higher IL-6, HSP-70, and GH expression levels than other treatments (P < 0.05). Sea trout fed D4 and D5 diets showed significant improvements in growth performance compared to the fish fed the control diet. In conclusion, our results suggest that dietary supplementation with the product BGN-2 provides great immunostimulation and could be used as an effective measure to improve growth performance in juvenile sea trout.