Line of action:

Status:

Execution date:

General Objective:

Design and validation of a suitable diet for mugylids (Chelon labrosus) that replaces fishmeal with by-products from the agri-food sector.

Specific objectives:

1. Proper project management
2. To increase scientific knowledge about nutrition, pathology and animal husbandry
3. Improving species growth rates
4. Increase animal welfare, health and immune status
5. To achieve the maximum inclusion of by-products in diets
6. Improve the nutritional quality of the final product
7. Train the sector (companies, scientists and students) about the results
8. Communicate and disseminate the project to the public
9. Continuity of the project after its execution

The MUGILDIET project has obtained juvenile liseta (Chelon labrosus, Liza aurata and Liza ramada) from the capture of wild specimens throughout the Bay of Cadiz. The survival rate for these species is over 40%. 6 experimental diets have been designed that, on the one hand, reduce the proteins provided by fishmeal and, on the other, allow a reduction in the cost of the diets, optimizing nutrient levels and covering the needs at each stage of growth of the fish.

For the production of the experimental feed, fishmeal, fish oil, macroalgae and different by-products of the brewing industry have been used as raw material. Six different diets have been formulated, ranging from a 30% replacement of fishmeal to a 70% reduction.

The results do not reflect significant differences in the growth of the specimens depending on the feed used. The satiety of the fish and their correct growth has made it possible to lower feeding rates to 1.5% per day. This represents a saving of between 2% and 2.5% per day in Kg feed/Kg of farmed fish over the total biomass. The costs of manufacturing experimental diets are around €480-500/tonne, significantly lower than the cost of other commercial feeds, with prices ranging from €962/tonne to €1,400/tonne. Four experiments have been carried out, two with Liza aurata and two with Liza ramada. The results have indicated that waste yeasts could be excellent candidates to replace fishmeal in mugilid diets.

The results of the salinity experiments indicated that the marine diet can help a perfect acclimatization to hypoosmotic environments of the specimens of Chelon labrosus, showing in turn a high metabolic plasticity, being able to adapt to environments of different salinity regardless of the diet used. The development of the immunological experiments has not reflected differences compared to the commercial diet.

The project has increased knowledge of alternatives to mugilid diets and progress has been made in the design and formulation of experimental diets, which have served to increase scientific knowledge in nutrition, pathology and zootechnics through the different tests and assessments carried out on the growth and nutritional and immunological responses of the individuals subjected to trials.