Mannan oligosaccharides supplementation enhanced head-kidney and spleen immune function in on-growing grass carp (Ctenopharyngodon idella)

• DOI: 10.1016/j.fsi.2020.08.035
• Publication Date: 2020-08-22T05:43:27Z
• Authors: Zhi-Yuan Lu; Wei-Dan Jiang; Pei Wu; Yang Liu; Sheng-Yao Kuang; Ling Tang; Juan Yang; Xiao-Qiu Zhou; Lin Feng
• Keywords: 0301 basic medicine; Carps; Dose-Response Relationship, Drug; Oligosaccharides; Head Kidney; Animal Feed; Aeromonas hydrophila; Diet; Mannans; Fish Diseases; Random Allocation; 03 medical and health sciences; Dietary Supplements; Animals; Gram-Negative Bacterial Infections; Spleen; Signal Transduction

This research investigates the influences of dietary mannan oligosaccharides (MOS) on the head-kidney and spleen immune function in on-growing grass carp (Ctenopharyngodon idella) and its related mechanism. Fish were fed during 60 days at different levels of MOS (0, 200, 400, 600, 800 and 1000 mg kg-1). Subsequently, 14 days after the feeding trial was injected intraperitoneally with Aeromonas hydrophila, the immune function was studied. The results are as follows: (1) appropriate MOS supplementation could increase the content of antibacterial compound and immunoglobulin (Ig), up-regulate antimicrobial peptides transcriptional levels in these two organs; (2) appropriate MOS supplementation attenuated inflammatory response in these two organs by regulating cytokines (pro- and anti-inflammatory cytokines) and related signalling pathways (NF-κB and TOR). The interesting points though, was, no differences were found in liver-expressed antimicrobial peptide (LEAP)-2A, interleukin (IL)-8, IL-4/13B, IκB kinase (IKK) α and nuclear factor kappa B (NF-κB) p52 gene expression in these two organs. Consequently, the present research suggests that MOS supplementation can enhance head-kidney and spleen immune function. Finally, we obtained these appropriate MOS dose (538.5 and 585.8 mg kg-1) by quadratic regression analysis of lysozyme activity (head-kidney) and phosphatase activity (spleen), respectively.