Aquaculture Feed and Fertilizer Resources Information System

European seabass - Feed production

Use of live food during early larval rearing

Under farming conditions, following the mouth opening (days 3 to 5 post-hatch), the larvae are fed live prey such as rotifers with or without algae, and Artemia, which are also normally enriched using different enrichment media before weaning onto formulated commercial feeds. The feeds distributed at this stage are extremely small particles, corresponding to the mouth opening: 50–250 μm for larvae of 8–10 mm, 180–400 μm for larvae of 20 mm and 315–600 μm for juveniles of 25 mm.

The rough scheme for the production of larvae is as follows:

Efforts over the years have been towards reducing some sequences, such as feeding rotifers and reducing the duration of total feeding with live prey through co-feeding or “weaning” to dry particulate feeds at an early date. It is not uncommon these days to have the whole sequence reduced to less than 40 days instead of more than two months, which was prevailing earlier. An example of a feeding sequence of live feeds is given in Table 3. The proximate/nutrient composition of live prey can vary considerably, and both rotifers and Artemia are enriched with different enrichment media to improve their nutritional values.

There has also been much progress accomplished in recent years in order to develop formulated complete feeds for rearing European seabass larvae right from the first feeding onwards (Cahu et al., 1998). Based on knowledge gained from different species on the ontogenetic changes occurring in the digestive system, it has been possible to develop specific feeds capable of ensuring as good growth and survival as with live prey (Cahu and Zambonino Infante, 2001). A few examples of larval microdiets are given in Table 4.

Formulated feeds

Industrially processed feeds are used to grow European seabass right from weaning larvae to feeding broodstock fish. These feeds are produced either using a simple pelleting process or most often, by using an extrusion process. The diameter of the pellets can vary from 60–80 µm to more than 9–10 mm (Table 5), depending on the size of fish. Most feeds used are sinking pellets, except in rare cases where floating pellets are used especially for purposes of feed management control. Feeds are delivered to the farms, packed as bags of 25 kg or as big (500 kg) bags (Figure 8). Following legal requirement, the label of each bag will list the major ingredients used and the proximate composition. Feeds are delivered to the farm sites using boats (Figure 9).

Feed ingredients

Feedstuffs of both marine and plant origin are used in the formulation of feeds for the European seabass. As regards protein sources, processed animal products are not commonly used in Europe. A short list of major ingredients used as protein/amino acid sources and their nutritional values are provided in Table 6. With regard to fatty acid sources, a list of oils and their major fatty acid profiles is also presented (Table 7).


A number of formulae are used by feed manufacturers, using the general nutritional constraints presented in Table 2. The feeds are formulated by the individual feed manufacturers using one of several least-cost formulation software programs. They generally contain a mixture of different protein/amino acid sources, fatty acid sources, vitamins, minerals and trace elements. The micronutrients are generally included in the form of premixes (Tables 8 and 9).  In recent years, much progress has been made in reducing the level of fishmeal in the feeds for European seabass (Kaushik et al., 2004). Feed formulae are generally determined by nutrient availability and digestible energy levels. Some data on the apparent digestibility coefficients of selected feed ingredients are reported in Table 10. A few feed formulae used at a large scale to demonstrate the possibility of reducing the fishmeal levels (Table 11) and on replacement of fish oil by a mixture of vegetable oils (Table 12) are reported.

Feed additives

A number of commercial additives are available that are used to a greater or lesser extent by different feed manufacturers; these include mould inhibitors, immunostimulants and pre- or probiotics. Addition of phytase in feeds containing phytic acid-rich plant ingredients has been found to be beneficial in improving phosphorus availability in European seabass (Oliva-Teles et al., 1998).

Feeding schedules

Larval feeds are distributed using belt feeders or other specially developed feed dispensers. In cage culture operations, both hand feeding based on feeding tables provided by feed manufacturers (Table 13) and the use of mechanical feed distributors occurs. Commercial cage farms (Figures 10 and 11) use hand feeding as well as automatic feeders combined with video monitoring of feeding behaviour.