Effects of zinc sulfate (ZnSO4) in diet on the growth performance and gene expression of Insulin-like growth factor-1 (IGF-1) and Ghrelin in goldfish (Carassius auratus)

The zinc element (Zn) is one of the micronutrients and an essential element of the body which has some deleterious and irreparable effects on growth in case of lack it. Thus, we aimed to assess IGF-1 in goldfish with Zn deficiency and to investigate the effect of Zn supplementation on these parameters. Goldfish  (Carassius auratus)  juvenile  (3.5 g)  were fed purified diets based on casein as a protein source and containing different levels of supplementary zinc sulfate (0, 25, 75 and 150 mg ZnSO4/kg diet) for 60 days. The results showed that fish fed with a diet supplemented with 150 mg kg-1 Zn had a significantly (P < 0.05) greater specific growth rate and lower feed conversion ratio than those fed with the diets of 0, 25 and 75 mg kg-1 ZnSO4. The results revealed that administration of zinc sulfate significantly (P < 0.05) up regulated Insulin-like growth factor-1 (IGF-1) gene expression. IGF-1 gene expression was significantly (P < 0.05) higher in zinc sulfate fed fish at the end of trial. Collectively, our results indicate that ZnSO4 stimulates Insulin-like growth factor-1 secretion from the liver at the post-transcriptional level.