Optimizing Feeding Strategies for Growth and Profitability in Caged European Sea Bass (Dicentrarchus labrax)

Abstract

This study aimed to verify, under natural farm conditions, the effect of increasing the daily feeding frequency at different meal intervals on zootechnical performance and feeding efficiency in the cultivation of caged European sea bass (Dicentrarchus labrax) . Feeding cost calculations according to each performance allowed us to define the most cost-effective and optimal protocol. The experiments were conducted for 117 days in 12 small floating net cages attached to an offshore farm system under natural conditions. A total of 1440 farmed sea bass with an initial average body weight of 43.9 ± 0.9 g were divided into four batches of 360 fish. Each batch corresponded to the following feeding frequency and intervals between meals: two daily meals with a 6 h interval (F26) (control), two daily meals with a 3 h interval (F23), three daily meals with a 3 h interval (F33), and three daily meals with 6 h interval (F36). Each batch consisted of three replicates (cages). The results showed that two protocols distinguished themselves—F23 recorded a significantly higher survival rate SR (97.50 %) and a lower final weight variation coefficient (CV f ;12.42 ± 0.12 %) while F33 recorded the highest final body length (Bl f , 20.60 ± 0.17 cm), final body weight (W f , 122.72 ± 1.26 g), daily growth rate (0.67 ± 0.01 g/d), and weight gain (Wg, 78.75 ± 1.73 g). The specific growth rate was higher in F33 (0.88 ± 0.02 % d −1 ) but did not differ significantly from other protocols. F23 showed the best feed conversion rate (FCR, 1.68 ± 0.03). The number of daily meals significantly affected W f , CV f , and Bl f when the meal interval had a significant impact on W f , CV f , Wg, and FCR. The calculated total feeding cost (TFC) was significantly affected by the number of meals per day and the intervals between meals. Compared with the control (F26), F23 showed the highest economic performance, with a 7 % reduction in TFC, whereas F33 showed a 1 % reduction. TFC increased by 4 % in F36. The feeding patterns under the experimental conditions examined revealed that feeding twice a day with a 3 h interval could be the most efficient and profitable feeding protocol in the growth phase, with an average body weight of 40–120 g for caged Dicentrarchus labrax .