Abstract
Prebiotics as a new approach in aquaculture are long-chain complex carbohydrates that provide energy to beneficial microorganisms/probiotics to improve growth, immunity, disease resistance, and animal tolerance to stressors. Plant-based products (beans, seaweed, fruits, microalgae, and vegetables), edible mushrooms, yeast, and animal dairy products are major prebiotic sources. Although prebiotics can increase feed utilization efficiency, such functions can be largely influenced by type, dosage, and duration use of prebiotics. Gut microbiota of aquatic organisms plays many functions including growth promotion, pathogen reduction, nutrient- and receptor competition, antimicrobial production, and metabolic activities, but various factors can influence their immune-physiological modulation. Endogenous bacteria of Gram-positives, especially lactic acid bacteria and Bacillus, are the most used probiotics in aquaculture. Diversity of beneficial products by probiotics for improving nutrient utilization, immunity modulation, disease resistance, and bioremediation of aquaculture water quality has been developed, but some detailed mechanisms of actions warranted future studies. Probiotics efficacy to the host nutrition and health status is through providing sources of macro- and micro-nutrients, vitamins, digestive enzymes, and secretion of diverse antimicrobials. Use of prebiotic and probiotics in aquaculture can provide a desirable condition to produce chemical/antibiotic-free aquaculture product.