The Effects of Grapevine (Vitis vinifera L.) Leaf Extract on Growth Performance, Antioxidant Status, and Immunity of Zebrafish (Danio rerio)

Abstract

An 8-week feeding trial was carried out to evaluate the effects of grapevine (Vitis vinifera) leaf extract (GLE) on the growth, oxidative enzymatic activities, immunity, and expression of antioxidant genes in zebrafish (Danio rerio). Three hundred and sixty zebrafish were supplied and fed with different levels of GLE: 0, 0.5, 1, and 2 g kg−1. The dietary administration of 1 g kg−1 of GLE significantly increased growth parameters in fish. Fish fed diets with GLE showed increased total protein. The total Ig and lysozyme activity significantly changed in the whole-body serum, but not in skin mucus. GLE significantly increased Catalase (CAT), Superoxide Dismutase (SOD), and Glutathione Peroxidase (GPx) activities compared to the control diet. GLE treatments caused a significant decrease in the malondialdehyde (MDA) content. In the skin mucus, only CAT and SOD activities significantly increased. The highest expression of Toll-like receptor-1 (TLR-1) and Tumor Necrosis Factor-α (TNFα) genes was achieved in fish fed 2 g kg−1 of GLE. CAT and SOD gene expressions were significantly higher in fish fed 1 and 2 g kg−1 of GLE. GPx gene expression was significantly higher in fish fed 1 g kg−1 of GLE. In conclusion, the results of the present study revealed that GLE affects growth performance and regulates antioxidant and immune gene expression. The determination of the optimum dosage merits further research.