Feeding frequency for dusky grouper Epinephelus marginatus juveniles with automatic feeding system

Abstract

Salt-water recirculation systems using automatic feeders are a new frontier for marine aquaculture. The definition of the feed frequency is fundamental for the correct use of automatic feeders. Different feeding frequencies (1, 3, 6, 12 and 18 times a day) using automatic feeders were evaluated in two experiments on the performance of the dusky grouper (Epinephelus marginatus) in salt-water recirculation system. In the first experiment, three feeding frequencies were evaluated: feeding once a day; three times a day and six times a day. In the second experiment, three feeding frequencies were evaluated: feeding six times a day; 12 times a day and 18 times a day.Waters parameters (temperature, salinity, oxygen level, total ammonia, pH and oxidation-reduction potential) were maintained at specific ranges for the species. Among all the evaluated frequencies, 12 times a day provided the best productive performance, obtaining superior results for final weight, final biomass, specific growth rate and daily weight gain. For juveniles of the dusky grouper, the ideal feeding frequency is regular feedings every 2 hours, which is impractical to run without the use of automatic feeders.

Performance of juvenile dusky grouper ( Epinephelus marginatus Lowe, 1834) fed different practical diets in an indoor water‐recirculation system

“…; Shapawi et al, 2011). Present FCR values observed in treatments fed the reference fish meal diet (AQT) were lower compared with previously reported values for dusky grouper using dry or moist diets (López & Castello-Orvay, 2003;Ramos et al, 2012;Sanches et al, 2007;Sousa et al, 2019) and were similar to other consolidated farmed marine fish species (Aas et al, 2019;Company et al, 1999;Raggi et al, 2019;Rosenlund et al, 2004;Tacon & Metian, 2015). As expected, FCR was lower for dry diets compared with semi-moist and fresh fish diets, which is in agreement with previously reported for tropical carnivorous marine fish (Bunlipatanon et al, 2014;Ma et al, 2020;Raggi et al, 2019), including grouper species (Muyot et al, 2021;Nugraha & Rozi, 2020;Ramos et al, 2012;Shapawi et al, 2011;Sim et al, et al, 1991).…”

“…The species is known to be docile, sedentary and having low energy expenditure as previously showed (Sanches et al, 2014;Sousa et al, 2019;Souza et al, 2014). Dusky grouper is an emerging species in Brazil with high market value (Lobo, 2021), whose grow-out cycle in Southeast region comprises 1.5 year to reach 1 kg fish.…”

“…The bulk of literature on dusky grouper farming, Epinephelus marginatus, reports experiments on species adaptation to farming and management, reproduction and feeding (Kerber et al, 2012;López & Castello-Orvay, 2003;Sousa et al, 2019;Yoshimini et al, 2019).…”

“…These studies often use generic commercial diets, formulated for other marine fish species and include testing fish, crustacean-and mollusk-based moist diets (Araújo et al, 2018;Kerber et al, 2012;López & Castello-Orvay, 2003;Ramos et al, 2012;Sanches et al, 2007;Sousa et al, 2019). In addition, these studies mostly employed fish collected from the wild which may have affected grouper performance.…”

“…To date, the culture of the dusky grouper is still in its infancy, as is information concerning its dietary nutrient requirements. As such, studies conducted to date have been limited to test the efficacy of fresh diets such as fresh fish, mussels and other non-specific commercial fish diets (López & Castello-Orvay, 2003;Ramos et al, 2012;Sanches et al, 2007Sanches et al, , 2014 and to determine optimum feeding frequencies (Sousa et al, 2019).…”