Dietary supplementation of black mulberry (Morus nigra) syrup improves the growth performance, innate immune response, antioxidant status, gene expression responses, and disease resistance of Nile tilapia (Oreochromis niloticus)

Abstract

The present study investigated the effects of black mulberry (Morus nigra) syrup supplementation on growth performance, hematological, serum biochemical, innate immune parameters, immune and antioxidant related gene expression responses, and disease resistance of Nile tilapia, Oreochromis niloticus. Five isonitrogenous and isoenergetic diets were formulated to contain black mulberry syrup at levels of 0%, 0.75%, 1.5%, 2.0%, and 3.0%. Fish were fed experimental diets for 60 days. Dietary black mulberry syrup increased activities of serum lysozyme, myeloperoxidase, superoxide dismutase and catalase, and increased the expression levels of immune-related genes (interleukin 1, beta, tumor necrosis factor, immunoglobulin M, interferon gamma and heat shock protein 70) in the spleen and antioxidant-related genes (superoxide dismutase, catalase and glutathione peroxidase) in the liver of fish fed especially with 1.5%, 2.0%, and 3.0% black mulberry syrup supplemented diets. Furthermore, at 2.0% incorporation level, growth performance increased.The findings of the present study indicate that Nile tilapia fed with diet containing 2.0% black mulberry might be adequate to improve the growth performance, innate immune parameters, antioxidant related gene expression responses, and disease resistance against Aeromonas veronii.