Sea Bream: Enhanced feeding recommendations and seasonal feed programs

August 15 2018

BioMar's recent research confirms and expands the knowledge about the effects of temperature on sea bream performance. The findings will soon be applied in our feeding recommendations for sea bream, in the BioMar Feeding Tool and in a complete seasonal feed program for sea bream.

- Sea water temperature has a direct impact on chemical reactions in the fish body and a direct influence on oxygen available for the fish. In the Mediterranean environment, temperatures vary from as low as 9 °C up to above 30 °C, in some areas. This of course affects farming performance. That is why this topic has been the focus of BioMar's R&D for a number of years, says Iannis Karacostas, Product Manager for the marine segment in BioMar EMEA.

New and thorough research is currently being carried out at BioMar's Aquaculture Technology Center (ATC) in Hirtshals, Denmark. This research looks into the relation between temperature and digestible energy of the feed on fish performance of sea bass, sea bream and trout. Results for sea bream are already available.

- Back in 2012, we had strong results showing how fish growth is independent from the digestible energy in the feed, at a given energy intake level and for a given temperature range. The new trials have a more developed set up and include wider ranges of water temperatures and of digestible energy levels on the feed. The outcome is a more detailed knowledge: irrespective of level of digestible energy (DE) in the feed, there is a clear division in the performance of sea bream at 16°C and below and at 20 °C and above, especially when using low energy feeds, said Iannis Karacostas.

With the hypothesis that the influence of temperature on the speed of growth of the fish does not depend on the size of the fish, the test allowed for calculating the correction curves for both SGR and FCR. - In fact, by applying temperature corrections to the curves for FCR and SGR, we now can establish curves for feeding tables that increase the accuracy of our feeding guides, stated Iannis Karacostas.

The trials also came with another very interesting finding: the digestibility coefficients of different components in the diet vary with temperature. This means that also the DE level of a given feed varies with temperature.
- This actually helps to explain why the growth of sea bream is reduced at low temperature, said Iannis Karacostas. - A practical conclusion is that in order to secure some remaining growth during winter time, it will help the fish if we use feed components with a higher digestibility. This can be done by the use of a feed with a higher digestible protein / digestible energy ratio and a lower overall energy level.

Iannis Karacostas comments that all the data from the trial strongly support the benefits of seasonal feed programs in which BioMar now incorporate these latest research results:

– BioMar offers feed types that cover the needs of the fish during the different periods of the year. I can proudly say that we have a rounded and well-documented feed program. Our program combines higher energy feeds when temperatures are optimal, feed with immune-boosting properties during periods of rapid changes - like spring and autumn- , and in cold water the program proposes lower energy feeds that have shown to perform well and even better than high energy diets. And of course for sea bream, the program also includes feeds targeted for the ectoparasites outbreaks' periods, concluded Karacostas.