Daniel González-Silvera

Mediterranean fouling communities assimilate the organic matter derived from coastal fish farms as a new trophic resource

Currently, the lipid content of fish feeds includes high amounts of terrestrial vegetable oils, rich in n-6 fatty acids and poor in n-3 fatty acids. Sinking organic matter in the shape of fragmented pellets and fish faeces could be ingested by the surrounding fauna attracted to the submerged structures of aquaculture facilities or living in natural benthic habitats. Fatty acids contained in feed pellets were used as trophic markers to shed light on the assimilation and incorporation of aquaculture wastes by the invertebrate fauna associated to sea-cages. Eighteen macroinvertebrate species, and zooplankton, seaweeds and sediments were collected from two fish farms, one of which (control) had not been used as such for two years. This study demonstrates that macroinvertebrate fauna present in fouling can take up sinking organic matter from farms. Further research should be directed at assessing the potential implications of aquaculture production for the surrounding ecosystem.

The freshwater alga Chroothece richteriana (Rhodophyta) as a potential source of lipids

During an ecological study of Chroothece (Rhodophyta) in a small river in a semi-arid region of south-east Spain it became clear that most of these cells had a high lipid content. This suggested potential uses in biotechnology, which has been investigated further. The colonies, which occur in full sunlight, are typically orange-brown. Most, perhaps all, the yellow-orange colour is associated with their high carotenoid content, with the carotenoid to chlorophyll ratio up to 2.7. The polyunsaturated fatty acyl composition of the glycerides was 35.3% of the dry weight. This consisted mainly of omega-3 (5.9%) and omega-6 (29.4%) fats. The relatively high proportion of docosahexaenoyl (1.78%), eicosapentaenoyl (14.15%), arachidonoyl (0.92%) and γ-linolenoyl (0.78%) suggests use for medical and dietary purposes. All cells have a high phycocyanin content whilst phycoerythrin is absent. The alga has a wide distribution globally and hence provides scope for selecting strains with optimum properties.

Cell-Based Assay To Quantify the Antioxidant Effect of Food-Derived Carotenoids Enriched in Postprandial Human Chylomicrons

We developed a new method to evaluate the antioxidant effect of food products in a biological system. The antioxidant status of HepG2 cells was quantified after incubation with postprandial human chylomicrons after the intake of vegetable products. Three subjects consumed in a meal a vegetable soup containing 8.4 mg of β-carotene and 9 mg of lycopene. After 5 h, the subjects consumed a second meal without carotenoids. Blood samples were collected at basal time and every hour for 9 h. Chylomicrons were isolated from serum samples and used for both carotenoid quantification and HepG2 stimulation. Carotenoid in chylomicrons followed an inter-individual and bimodal carotenoid response. We demonstrated the antioxidant effect of postprandial chylomicrons in HepG2 at the time of maximum carotenoid concentration of chylomicrons with respect to basal time. This cell-based assay seems to be a useful method to evaluate the antioxidant effect of fruit and vegetable products in a biological system.

Caracterización y valor nutritivo de un alimento artesanal: el pastel de carne de Murcia

OBJECTIVES The main aims of this study are to describe the characteristics of the meat pie, a typical product of the regional gastronomy of Murcia and to determine its nutritional and energy values, fatty acid profile and fat quality. METHODS There were studied 24 samples of Murcias meat pie from the six best-selling retail establishments in this Region (four units per establishment).The moisture, protein, fat, carbohydrates, fibre and minerals, contents and the energy value, fatty acid profile and fat quality were analyzed using the Official Analysis Methods of Foods. All analyses were performed by triplicate. RESULTS AND DISCUSSION The average weight of this product was 192.3 ± 11.8 g, with three differentiated parts (base, filling and pastry lid). All ingredients were natural raw materials: wheat flour, lard, ground beef, sliced boiled egg and chorizo, water and spices (salt, pepper, garlic, paprika and nutmeg). Most of its organoleptic attributes are due to the type and amount of fat or lard. The combination of the other ingredients and the particular formulation of the spices are also responsible of other attributes. Due to its protein content (11.0%), this meat pie can replace other meat dishes, and be incorporated into a balanced diet. However, it is necessary to take into account its fat and energy contents (17.3 g and 317 kcal/100 g, respectively). Unlike many common pastry products, it contains no trans fatty acids. CONCLUSIONS The results of the research show that the studied product remains, at present, an artisan food, and offer reliable information that it is representative of the energy and nutritional values of the Murcias meat pie, a typical product of the gastronomy of the Region of Murcia.

The short-term effects of farmed fish food consumed by wild fish congregating outside the farms

We simulated in the laboratory the possible effects on fatty acids and immune status of wild fish arriving for the first time in the vicinity of a sea-cage fish farm, shifting their natural diet to commercial feed consumption, rich in fatty acids of vegetable origin. The flesh fatty acid profile of golden mullet specimens was altered after 2weeks of commercial feed consumption, showing an increase in fatty acids of vegetable origin. The serum peroxidase and bactericidal activities, and head-kidney leucocyte phagocytic capacity, increased after eight weeks of the new diet, while the respiratory burst activity decreased. The extent of these changes cannot be considered large enough to regard them as compromising the health status of fish. More research is needed in order to elucidate whether the rapid assimilation of the dietary fatty acids could harm the immune status of fish when feeding for longer periods than two months.

EFFECT OF LONG TERM INTAKE OF WHITE TEA ON ACUTE OXIDATIVE STRESS IN RATS.

INTRODUCTION the well known antioxidant properties of white tea include the prevention of cancer, neurodegenerative diseases and oxidative stress. Adriamycin can generate an amount of oxidative stress in vivo. OBJECTIVE evaluate long term intake of white tea on plasma antioxidant capacity and on the fatty acid profile of liver and heart microsomes in animals subjected to acute oxidative stress. METHODS rats were given distilled water (controls), 15 mg/d (dose 1) or 45 mg/d (dose 2) of solid white tea extract/per kilogram of body weight for 12 months. After this time, all the animals received an injection of adriamycin (ADR) (10 mg/kg body weight), except half of the control group, which were given an injection of saline solution. Samples of plasma and liver and heart were taken. The antioxidant activity, the carbonyl groups and hydroperoxide concentration were analyzed in plasma, and the fatty acid profiles of liver and heart microsomes were obtained. RESULTS & DISCUSSION only the hydroperoxides showed significant changes, while slight tendencies were observed in antioxidant activity and the carbonyl groups. Although the long term intake of white tea and the administration of adriamycin did not change the fatty acid profile, slight tendencies existed for the SFAs, MUFAs and PUFAs.

Effects of global change factors on fatty acids and mycosporine-like amino acid production in Chroothece richteriana (Rhodophyta)

Under natural conditions, Chroothece richteriana synthesizes a fairly high proportion of fatty acids. However, nothing is known about how environmental changes affect their production, or about the production of protective compounds, when colonies develop under full sunshine with high levels of UV radiation. In this study, wild colonies of C. richteriana were subjected to increasing temperature, conductivity, ammonium concentrations and photosynthetically active radiation (PAR), and UV radiations to assess the potential changes in lipid composition and mycosporine‐like amino acids (MAAs) concentration. The PERMANOVA analysis detected no differences for the whole fatty acid profile among treatments, but the percentages of α‐linolenic acid and total polyunsaturated fatty acids increased at the lowest assayed temperature. The percentages of linoleic and α‐linolenic acids increased with lowering temperature. γ‐linolenic and arachidonic acids decreased with increasing conductivity, and a high arachidonic acid concentration was related with increased conductivity. The samples exposed to UVB radiation showed higher percentages of eicosapentaenoic acid and total monounsaturated fatty acids, at the expense of saturated fatty acids. MAAs accumulation increased but not significantly at the lowest conductivity, and also with the highest PAR and UVR exposure, while ammonium and temperature had no effect. The observed changes are probably related with adaptations of both membrane fluidity to low temperature, and metabolism to protect cells against UV radiation damage. The results suggest the potential to change lipid composition and MAAs concentration in response to environmental stressful conditions due to climate change, and highlight the interest of the species in future research about the biotechnological production of both compound types.