Current applications, selection, and possible mechanisms of actions of synbiotics in improving the growth and health status in aquaculture: A review.
Synbiotics, a conjunction between prebiotics and probiotics, have been used in aquaculture for over 10 years. However, the mechanisms of how synbiotics work as growth and immunity promoters are far from being unraveled. Here, we show that a prebiotic as part of a synbiotic is hydrolyzed to mono- or disaccharides as the sole carbon source with diverse mechanisms, thereby increasing biomass and colonization that is established by specific crosstalk between probiotic bacteria and the surface of intestinal epithelial cells of the host. Synbiotics may indirectly and directly promote the growth of aquatic animals through releasing extracellular bacterial enzymes and bioactive products from synbiotic metabolic processes. These compounds may activate precursors of digestive enzymes of the host and augment the nutritional absorptive ability that contributes to the efficacy of food utilization. In fish immune systems, synbiotics cause intestinal epithelial cells to secrete cytokines which modulate immune functional cells as of dendritic cells, T cells, and B cells, and induce the ability of lipopolysaccharides to trigger tumor necrosis factor-α and Toll-like receptor 2 gene transcription leading to increased respiratory burst activity, phagocytosis, and nitric oxide production. In shellfish, synbiotics stimulate the proliferation and degranulation of hemocytes of shrimp due to the presence of bacterial cell walls. Pathogen-associated molecular patterns are subsequently recognized and bound by specific pattern-recognition proteins, triggering melanization and phagocytosis processes.
Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung 912, Taiwan, ROC; College of Aquaculture and Fisheries, CanTho University, CanTho, Viet Nam.
Truong-Giang
TG
Huynh
Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung 912, Taiwan, ROC.
Ya-Li
YL
Shiu
College of Aquaculture and Fisheries, CanTho University, CanTho, Viet Nam.
Thanh-Phuong
TP
Nguyen
College of Aquaculture and Fisheries, CanTho University, CanTho, Viet Nam.
Quoc-Phu
QP
Truong
Department of Aquaculture, College of Life Sciences, National Taiwan Ocean University, Keelung 202, Taiwan, ROC.
Jiann-Chu
JC
Chen
Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung 912, Taiwan, ROC. Electronic address: chliu@mail.npust.edu.tw.
Chun-Hung
CH
Liu
D000818:Animals; D017756:Aquaculture; D003445:Crustacea / Q000502:physiology; D005399:Fishes / Q000502:physiology; D008974:Mollusca / Q000502:physiology; D056692:Prebiotics / Q000032:analysis*; D019936:Probiotics / Q000032:analysis*; D058616:Synbiotics / Q000032:analysis*
D056692:Prebiotics
Aquaculture; Growth; Immunity; Prebiotic; Probiotic; Synbiotic metabolites