NUTRITION
Plant extracts support oxidative balance and promote growth in fish larvae and postlarvae Maria J. Xavier, Sofia Engrola, Luísa M.P. Valente, Luís Conceição, Sparos, CCMAR, CIIMAR, ICBAS
Nutrition has tremendous impacts on the growth, survival and health status of farmed fish, with both short- and long-term effects. Larvae rearing still holds a constrain in the development of marine fish production, as survival rates are often low or highly variable and growth potential is, in most cases, not fully utilized. Moreover, larval stages are sensitive periods, and correct ontogenesis will influence the quality of the juveniles. Therefore, optimizing microdiets formulation is a possible strategy to promote farm’s profitability. Microdiet optimization may encompass both fulfillment of the nutritional requirements of the fish species and also the inclusion of bioactive compounds. The use of plant extracts in fish diets has been gaining attention, due to the fact that they are economically attractive, environmentally friendly and present a wide spectrum of bioactive molecules. Polyphenols comprise the most abundant group of bioactive compounds and are present in a variety of plants, including seeds, spices and microalgae. The molecular structure of these phenolic compounds confers the antioxidant capacity. In addition, they can regulate the activity of the endogenous antioxidant system or synergize with it, promoting fish allostasis. This article summarizes a PhD study (Xavier M.J., 2021) aiming to provide a nutritional approach, with the use of plant extracts, to respond to the current challenges of marine hatcheries. Therefore, the potential of these natural additives as promoters of digestive capacity, oxidative status, and muscle growth in fish larvae and post-larvae was evaluated. The goal was to promote growth performance and health status at the early stages of development of two fish species, Senegalese
Hatchery Feed & Management Vol 10 Issue 1 2022
sole and gilthead seabream, important for SouthEuropean Aquaculture.
Screening of plant extracts as potential additives for microdiets A dietary screening of different plant extracts with high antioxidant capacity, such as curcumin, green tea and grape seeds, was performed in Senegalese sole. This initial trial was carried out at CCMAR facilities (Faro, Portugal) with 45 days after hatching (DAH) Senegalese sole postlarvae reared in a recirculating aquaculture system (RAS) and fed with experimental inert diets for 25 days. Postlarvae were fed with one of four diets: a commercial diet (CTRL treatment) and the other three
