Influences of makiang (Syzygium nervosum) seed powder on growth performance, immunological response, antioxidant and immune related gene expression in juvenile Nile tilapia (Oreochromis niloticus)

Abstract

A makiang seed powder (MSP) feeding trial was performed on Nile tilapia (Oreochromis niloticus) for eight weeks to evaluate the effects on growth performance, immune response, and gene expression. Three hundred fingerlings (13.20 ± 0.04 g) were fed five diets with various amounts of MSP at 0, 5, 10, 20 and 40 g kg−1. After four and eight weeks of the feeding trial, growth rates and immune responses were tested, while relative immune and antioxidant gene expression were performed after eight weeks of MSP feeding. Accordingly, the growth indices (SGR, WG) and immune activity (skin mucus and serum lysozyme, skin mucus and serum peroxidase, alternative complement, phagocytosis and respiratory burst activities) in Nile tilapia were significantly increased in the treated diets compared with the control diet (P < 0.05). The maximum (P ≤ 0.05) growth and immune activity values were noted in fish fed 5 g kg−1 MSP. IL1, IL8, LBP, GPX, GSTa and GSR gene expressions were also shown to be upregulated in fish on MSP diets, with the highest value reported in fish fed 5 g kg−1 MSP. Finally, MSP has the potential to be employed as a feed supplement in the biofloc system for the cultivation of Nile tilapia.