Resumen de Millora de la salut i condició de les mucoses en peixos mitjançant l'ús de dietes funcionals en aqüicultura: fitogénicos com a additius per a aliments aqüícoles
Aquaculture growth will unavoidably involve the implementation of innovative and sustainable production strategies, being functional feeds among the most promising ones. A wide spectrum of phytogenics, particularly those containing terpenes and organosulfur compounds, have been gaining increasing interest in aquafeeds, due to their growth promoting, antimicrobial, immunostimulant, antioxidant, anti-inflammatory and sedative properties. Although the impact of phytogenics upon fish mucosal immunity has been extensively evaluated, most of the studies fail in addressing the mechanisms underlying their pharmacological effects. Under this context, the set of studies gathered in this thesis aims to provide insights on how fish mucosal tissues are immunomodulated by phytogenics, in particular by the administration of a microencapsulated feed additive composed by garlic essential oil, carvacrol and thymol. A holistic approach integrating both key performance indicators and the transcriptional immune response of three selected mucosal tissues – gill, intestine and skin – was applied in one of the most important marine fish species farmed in the Mediterranean Sea, the gilthead seabream (Sparus aurata). The overall analysis of the results indicated that the dietary supplementation of garlic, carvacrol and thymol promote the gilthead seabream mucosal innate immunity and the mucus protective capacity, decreasing the mucosal tissues susceptibility to be infested by parasites and colonized by pathogenic bacteria, without compromising somatic growth or microbiota homeostasis. Therefore, the strategy evaluated is an effective and safe tool to be used in functional diets for aquaculture. Besides solving scientific questions, the overall results and added knowledge obtained from this industrial thesis aim to drive the development and consolidation of new nutritional tools that may be used to hamper emergent disease outbreaks related to the growth in intensive production systems and the increasing pressure of climate change.
