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.

Influence of Production Strategy on Gross Waste Output and Temporal Pattern of Gilthead Seabream (Sparus Aurata) Farming: Implications for Environmental Management

“…Another portion of the F s can be wasted due to inefficient control when dispensing the feed (feed supplied but unused: F u ). This is normally the consequence of inaccurate feed distribution over the cage surface or a feed delivery rate that is too rapid for the fish to ingest the feed properly [20,21]. The actual ingested feed (F i ) is equal to the difference between F s and the sum of the feed wasted in both ways (F ch + F u ).…”

“…How effectively aquaculture companies manage their waste has a considerable influence on long-term sustainability [19]. Waste output and environmental impact can be minimized through on-farm feeding management [20,21] and site selection [22]. The Mediterranean fish farming industry is in the process of changing its production strategy.…”

“…The expansion of aquaculture over the next few years should be accompanied by technical and management improvements to minimize environmental and social concerns [21,24]. Over the past few decades, several models have been developed to deal with different aspects related to the environmental management of aquaculture.…”

Probiotics Have the Potential to Significantly Mitigate the Environmental Impact of Freshwater Fish Farms

“…The optimal feeding of farmed fish necessitates an understanding of the digestion process, the digestive system, and the parameters that affect fish metabolism and why these parameters can influence feed conversion and the organic load generated by fish farms. Feed conversion varies significantly depending on the feed composition and management practices used in a fish farm [33]. The organic load and impact of freshwater fish farms in the aquatic ecosystem can be reduced by manipulation of the dietary regimes, for example, by adjusting the quantity of feed according to feed manufacturer feeding tables and by reducing the phosphorus content in the feed [24,29,[32][33][34][35].…”

“…Feed conversion varies significantly depending on the feed composition and management practices used in a fish farm [33]. The organic load and impact of freshwater fish farms in the aquatic ecosystem can be reduced by manipulation of the dietary regimes, for example, by adjusting the quantity of feed according to feed manufacturer feeding tables and by reducing the phosphorus content in the feed [24,29,[32][33][34][35]. The feed conversion ratio (FCR) is the common measure that quantifies the efficiency by which fish convert feed with respect to weight increase.…”