Combined Effects of Temperature and Dietary Lipid Level on Body Composition, Growth, and Freshness Profile in European Seabass, Dicentrarchus labrax

Simple Summary The effects of increasing temperature and dietary lipid level on the body composition, growth performance, and freshness profile of the European seabass (Dicentrarchus labrax) were evaluated through a fish trial lasting 56 days. Findings demonstrated that fish reared at 24 degrees C presented a lower lipid level and a higher daily growth index than those reared at 20 degrees C. On the other hand, the sea bass condition index did not change among treatments. Additionally, sensory analysis (the Quality Index Method) and microbiological analysis revealed that fish reared at 24 degrees C showed better freshness conditions than those at 20 degrees C. Nevertheless, the dietary lipid level did not have any influence on fish freshness conditions. Therefore, our data suggest that the increase in temperature to 24 degrees C is beneficial for the growth and freshness profile of this particular species in aquaculture. A fish trial was carried out to evaluate the combined effects of temperature and dietary lipid level on the body composition, growth performance, and freshness profile of the European seabass (Dicentrarchus labrax). Fish were kept for 56 days at 20 degrees C and 24 degrees C and fed on two diets, with 16% and 20% lipid. At the end of the trial, fish were euthanized at two temperature conditions (0.6 degrees C or -0.6 degrees C) and kept on ice for 10 days at 4 degrees C to evaluate their freshness condition. Findings demonstrated that fish reared at 24 degrees C presented a lower lipid level and a higher daily growth index than those at 20 degrees C. Additionally, sensory analysis (Quality Index Method-QIM) and microbiological analysis revealed that fish reared at 24 degrees C showed better freshness conditions than those at 20 degrees C. However, the 16S rRNA metabarcoding analyses revealed a higher proliferation of genera associated with fish-spoiling bacteria in the skin microbiome of fish reared at 24 degrees C, i.e., Vibrio and Acinetobacter, which was not observed in the skin microbiome of fish reared at 20 degrees C. Nevertheless, the dietary lipid level did not have any influence on fish freshness. Therefore, our data suggest that the increase in temperature to 24 degrees C is beneficial for the growth and freshness profile (lower QIM and lower CFUs/cm(2)) of this particular species. Additionally, the lower euthanasia temperature (-0.6 degrees C) seems to lead to higher fish freshness than the normal temperature (0.6 degrees C).

Automated summary

A fish trial was conducted to assess the effects of temperature and dietary lipid level on the body composition, growth performance, and freshness profile of the European seabass. The study showed that fish reared at 24 degrees C had lower lipid levels and higher daily growth index compared to fish reared at 20 degrees C. Sensory and microbiological analysis further revealed better freshness conditions in fish reared at 24 degrees C. However, dietary lipid level did not impact fish freshness. These findings suggest that increasing the temperature to 24 degrees C is beneficial for the growth and freshness profile of this particular species in aquaculture.