Effect of Feed Delivery Rate and Pellet Size on Rearing Performance, Feed Wastage and Economic Profitability in Gilthead Seabream (Sparus Aurata) Ongrowing

Abstract

Gilthead seabream (Sparus aurata) displays a particular eating behaviour that involves considerable oral manipulation and feed waste. We assess the influence of feed delivery rate and pellet size on seabream growth and size variability, feed wastage and economic profitability for a full production cycle. Batches of seabream were fed twice a day according to three different treatments (T1, T2, T3). T1 and T2 fish were fed with the same regime of pellet sizes: 2 mm pellets until the fish reached 0.1 kg, and 4 mm pellets from then on; the feeding rate in T1 was twice that of T2 (20 and 10 g min−1, respectively). T3 fish were fed with pellets of 2 mm until they reached 0.07 kg, with pellets of 4 mm until the fish reached 0.22 kg, and with 6 mm pellets from then on, with a feeding rate of 10 g min−1. T2 showed increased growth, low variability in fish size during the ongrowing and at harvest, less feed wastage both related to the delivery and the chewing behaviour, lower feed costs and improved profitability. Seabream wasted more feed during the second meal. Controlling the feeding process is essential to reduce wastage and increase profitability, which can be achieved by process monitoring and suitable feed pellet management.