No abstract

The nutritive quality of Nannochloropsis gaditana cultured semicontinuously with different daily renewal rates was tested as a diet for short-term enrichment of the rotifer Brachionus plicatilis. After 24 h, dramatic differences in the survival, dry weight, and biochemical composition of the rotifers depending on the renewal rate of microalgal cultures were observed. Survival after the feeding period increased with increasing renewal rates. Rotifers fed microalgae from low renewal rate, nutrient-deficient cultures showed low dry weight and organic contents very similar to those of the initial rotifers that were starved for 12 h before the start of the feeding period. On the contrary, rotifers fed nutrient-sufficient microalgal cells underwent up to twofold increases of dry weight and protein, lipid, and carbohydrate contents with regard to rotifers fed nutrient-depleted N. gaditana. Consequently, feed conversion rate decreased in these conditions, indicating a better assimilation of the microalgal biomass obtained at high renewal rates. No single microalgal biochemical parameter among those studied can explain the response of the filter feeder. Similarly to gross composition, EPA and n-3 contents in rotifers fed microalgae from nutrient-sufficient cultures were double than the contents found in rotifers fed nutrient-limited microalgae. In addition, very high positive correlations between the contents of EPA and n-3 in N. gaditana and B. plicatilis were observed. These results demonstrate that selecting the appropriate conditions of semicontinuous culture can strongly enhance the nutritional value of microalgae that is reflected in the growth and biochemical composition of the filter-feeder even in short exposure periods.

EU aquaculture produces only a small fraction of the internal demand of aquatic foods, but boosting this activity must be done in compliance with high standards of environmental protection and social benefits, as fostered by the policies on circular economy recently launched by the EU. Nevertheless, the assessment of the environmental sustainability of aquaculture and other food production systems is complex, due to the different tools and approaches available. Moreover, the current EU regulatory framework may be restricting the options to implement some circular solutions. This paper examines the controversies related to the assessment of environmental impacts of aquaculture processes and the different available circular solutions, with a focus on the best options to valorize aquaculture side streams and how current regulatory burdens and gaps should be solved.

No abstract

The present work is focused on the development of a TaqMan multiplex real-time PCR method for the detection of Salmonella, Shigella and L. monocytogenes in seafood, meat and ready-to-eat products. The aim of this study is to detect the three pathogens in one single test including an enrichment medium for the simultaneous growth of the bacteria of interest and an Internal AmpliWcation Control (IAC) to monitor PCR inhibitors. For this purpose, three genes were selected, invA for Salmonella, ipaH for Shigella and hlyA for L. monocytogenes. Also, no. 17 broth without dextrose and further modiWed by adding Tween 80 was used for the enrichment step. SpeciWcity of the method was checked against a panel of 24 non-target bacterial strains. RT-PCR eYciency obtained for the simultaneous ampliWcation of all three pathogens was 102.5% for Salmonella, 108.9% for Shigella and 106.4% for L. monocytogenes. The limit of detection (LOD) was evaluated in seafood, meat and ready-to-eat products, being established within 3 and 22 cfu in 25 g of sample for the three bacteria analyzed. Seventy-eight samples were analyzed with multiplex RT-PCR including spiked and natural samples collected from diVerent laboratories. Even though several RT-PCR methods have been developed for the detection of Salmonella, Shigella and L. monocytogenes, as far as we know this is the Wrst method developed for the simultaneous detection of these three pathogens, coupling RT-PCR with an enrichment in the same broth and being tested in a wide range of diVerent processed food samples with a low LOD. The application of this method can signiWcantly reduce costs and time of analysis in laboratories, what would be reXected in a faster response in those risk situations when they are detected.