Influence of quercetin loaded mesoporous silica nanoparticles (QMSNs) on immunity and diseases resistance in Nile tilapia (Oreochromis niloticus)

ABSTRACT The aim of the present study is to scrutinize the potentiality of Quercetin loaded mesoporous silica nanoparticles (QMSNs) to improve the disease resistance and immune response in Nile tilapia (Oreochromis niloticus). The study used five experimental groups of fish with a mean weight of 0.69 ± 0.31 g; three groups were fed quercetin loaded mesoporous silica nanoparticles (QMSNs) incorporated diets (0.25 g kg−1 – QMSNs 0.25, 0.50 g kg−1 – QMSNs 0.50, 1 g kg−1 – QMSNs 1), while the control group was fed an additive-free basal diet. The fifth group was a strict quercetin-only diet (0.25 g kg−1 – QMD). Feeding trial was done for 90 days prior to the experimental challenge with Klebsiella pneumoniae and Streptococcus agalactiae. Dietary quercetin loaded mesoporous silica nanoparticles (QMSNs) especially at 0.50 g kg−1 significantly increased digestive enzymes, phagocytic index, potential killing activity, respiratory burst activity, and Serum antibacterial activity. Furthermore, antioxidant-related genes [superoxide dismutase (SOD) and catalase (CAT)] and metabolic enzymes [serum glutamic oxaloacetic transaminase (AST) and serum glutamic pyruvic transaminase (ALT)] were found to be upregulated in the muscle and hepatopancreases of fish fed with 0.50 g kg−1 QMSNs. Survival rates were significantly higher in the 0.50 g kg−1 QMSNs group at the end of the 15th day challenge period compared to all other treatment groups. As a result, feeding Nile tilapia with 0.50 g kg−1 QMSNs for 90 days may be sufficient to improve fish immune response, antioxidant status, and survival rate against Klebsiella pneumoniae and Streptococcus agalactiae. As a result, quercetin loaded mesoporous silica nanoparticles (QMSNs) can be recommended as a dietary substitute against K.pneumoniae and S. agalactiae in Nile tilapia.