Fatty acid metabolism in isolated enterocytes from salmonid fish.

Considering the results found, through in vivo experimentation, that intestine of trout and specifically pyloric caeca was an important site of metabolic activity (Bell et al., 2003c), it was contemplated to begin with a research project to demonstrate and establish the rate in which n-3 HUFA are synthesised by intestinal cells using in vitro assays. The aim of the research work was to determine the importance of intestine and caecal enterocytes in fatty acid metabolism in salmonids, focusing on their potential role in HUFA synthesis and the effects of replacement of fish oil (FO) with vegetable oils (VO) in the diets. The results of the investigation gave answer to the most important questions about intestinal metabolism of fatty acids and brought suggestions for future research work. A simple method for the isolation of viable enterocytes from salmonids suitable for use in both laboratory and fish farm conditions was established, and a method to analyse desaturation/elongation and P-oxidation activities in a single combined assay was developed. Pyloric caeca enterocytes were found to be more active than other intestinal tissues tested in terms of HUFA synthesis capacity and they were used for the evaluation of the following dietary trials. The performance of the HUFA synthesis assay in the enterocyte preparations was determined under a variety of parameters to standardize an assay protocol for use in all comparative studies. Regarding the effect of replacing FO with VO in diets for salmonids on fatty acid metabolism in enterocytes it was found that VO (a blend) can be good substitute for FO and can be use by the salmon industry without compromising the standard of quality of the product. Caecal enterocytes were not more active than hepatocytes and, irrespective of the diet, the primary fate of the substrate was P-oxidation rather than HUFA synthesis. HUFA synthesis in enterocytes and hepatocytes, increased in fish fed VO compared to fish fed FO and fish fed VO increased fatty acid oxidation activity in enterocytes whereas there was no dietary effect in hepatocytes

Protein hydrolysate from Pterygoplichthys disjunctivus, armoured catfish, with high antioxidant activity

Pterygoplichthys disjunctivus locally named as armored catfish ” is a by-catch of tilapia fishing which accounts for up to 80% of total captured fish in the Adolfo Lopez Mateos dam, in Michoacán, México affecting the economy of its surrounding communities. This invasive fish is discarded by the fishermen since native people do not consume it; partly due to its appearance yet is rich in protein. The aim of this study was to produce hydrolysates from armoured catfish using food grade proteases (neutrases HT and PF and alcalase PAL) and investigate process conditions (pH and temperature) that lead to high degree of hydrolysis, antioxidant activity, and Angiotensin I-Converting Enzyme (ACE) Inhibitory activity. No other similar research has been reported on this underutilized fish. The antioxidant activity was measured by three different methods, ABTS, FRAP, ORAC with relevance to food and biological systems in order to obtain a more comprehensive assessment of the activity. In addition, main peptide sequences were identified. All enzymes produced hydrolysates with high antioxidant activity. In particular, the protease HT led to the highest antioxidant activity according to ABTS (174.68 mol Trolox equivalent/g fish) and FRAP (7.59 mg ascorbic acid equivalent/ g fish) methods and almost the same as PAL according to the ORAC method (51.43 mol Trolox equivalent/g fish). Moreover, maximum activities were obtained at mild pH and temperature conditions (7.5; 50 °C). Interestingly, the ORAC values obtained here were higher than others previously reported for fish hydrolysates and similar to those reported for fruits such as, blueberries, apples and oranges. The peptide sequence IEE(E) was present in several peptides in both hydrolysates; this sequence may be partly responsible for the high antioxidant activity particularly for the one based on the iron reducing power. These findings will be relevant to the valorization of other fish/fish muscle discards and could contribute to the production of food supplements and nutraceuticals

Effects of dietary lipid level and vegetable oil on fatty acid metabolism in Atlantic salmon (Salmo salar L.) over the whole production cycle

Changes in fatty acid metabolism in Atlantic salmon (Salmo salar) induced by vegetable oil (VO) replacement of fish oil (FO) and high dietary oil in aquaculture diets can have negative impacts on the nutritional quality of the product for the human consumer, including altered flesh fatty acid composition and lipid content. A dietary trial was designed to investigate the twin problems of FO replacement and high energy diets in salmon throughout the entire production cycle. Salmon were grown from first feeding to around 2 kg on diets in which FO was completely replaced by a 1:1 blend of linseed and rapeseed oils at low (14-17%) and high (25-35%) dietary oil levels. This paper reports specifically on the influence of diet on various aspects of fatty acid metabolism. Fatty acid compositions of liver, intestinal tissue and gill were altered by the diets with increased proportions of C18 polyunsaturated fatty acids and decreased proportions of n-3 highly unsaturated fatty acids (HUFA) in fish fed VO compared to fish fed FO. HUFA synthesis in hepatocytes and enterocytes was significantly higher in fish fed VO, whereas β-oxidation was unaltered by either dietary oil content or type. Over the entire production cycle, HUFA synthesis in hepatocytes showed a decreasing trend with age interrupted by a large peak in activity at seawater transfer. Gill cell prostaglandin (PG) production showed a possible seasonal trend, with peak activities in winter and low activities in summer and at seawater transfer. PG production in seawater was lower in fish fed the high oil diets with the lowest PG production generally observed in fish fed high VO. The changes in fatty acid metabolism induced by high dietary oil and VO replacement contribute to altered flesh lipid content and fatty acid compositions, and so merit continued investigation to minimize any negative impacts that sustainable, environmentally-friendly and cost-effective aquaculture diets could have in the future.This article was subsequently updated, see revised version on Springer: http://dx.doi.org/10.1023/B:FISH.0000045722.44186.e

Diversification of substrate specificities in teleostei Fads2: characterization of Δ4 and Δ6Δ5 desaturases of Chirostoma estor

Currently existing data show that the capability for long-chain PUFA (LC-PUFA) biosynthesis in teleost fish is more diverse than in other vertebrates. Such diversity has been primarily linked to the subfunctionalization that teleostei fatty acyl desaturase (Fads)2 desaturases have undergone during evolution. We previously showed that Chirostoma estor, one of the few representatives of freshwater atherinopsids, had the ability for LC-PUFA biosynthesis from C18 PUFA precursors, in agreement with this species having unusually high contents of DHA. The particular ancestry and pattern of LC-PUFA biosynthesis activity of C. estor make this species an excellent model for study to gain further insight into LC-PUFA biosynthetic abilities among teleosts. The present study aimed to characterize cDNA sequences encoding fatty acyl elongases and desaturases, key genes involved in the LC-PUFA biosynthesis. Results show that C. estor expresses an elongase of very long-chain FA (Elovl)5 elongase and two Fads2 desaturases displaying Δ4 and Δ6/Δ5 specificities, thus allowing us to conclude that these three genes cover all the enzymatic abilities required for LC-PUFA biosynthesis from C18 PUFA. In addition, the specificities of the C. estor Fads2 enabled us to propose potential evolutionary patterns and mechanisms for subfunctionalization of Fads2 among fish lineages

Effects of diets containing linseed oil on fatty acid desaturation and oxidation in hepatocytes and intestinal enterocytes in Atlantic salmon (Salmo salar)

We hypothesized that replacing fish oil with 18:3n-3-rich linseed oil may enable salmon to maintain the levels of tissue n-3HUFA levels through a combination of increased desaturation activity and increased substrate fatty acid provision. To this end we investigated desaturation/elongation of [1-14C18:3n-3 in hepatocytes and intestinal enterocytes, and determined the extent to which 18:3n-3 was oxidized and desaturated by measuring both simultaneously in a combined assay. Salmon smolts were stocked randomly into five seawater pens and fed for 40 weeks on diets in which the fish oil was replaced in a graded manner by linseed oil. At the end of the trial, fatty acyl desaturation/elongation and oxidation activities were determined in isolated hepatocytes and intestinal enterocytes using [1-14C]18:3n-3 as substrate, and samples of liver and intestinal tissue were collected for analysis of lipid and fatty acid composition. The results showed that, despite increased desaturation of [1-14C]18:3n-3 in hepatocytes, provision of dietary 18:3n-3 did not prevent the decrease in tissue n-3HUFA in fish fed linseed oil. Intestinal enterocytes were a site of significant fatty acid desaturation but, in contrast to hepatocytes, the activity was not increased by feeding linseed oil and was generally lower in fish fed linseed oil compared to fish fed only fish oil. In contrast, oxidation of [1-14C]18:3n-3 in enterocytes was generally increased in fish fed linseed oil compared to fish fed the diet containing only fish oil. However, oxidation of [1-14C]18:3n-3 in hepatocytes was 4- to 8-fold lower than in enterocytes and was not affected by diet. Furthermore, oxidation of [1-14C]18:3n-3 in enterocytes exceeded desaturation irrespective of dietary treatment, whereas similar amounts of [1-14C]18:3n-3 were desaturated and oxidized in hepatocytes from fish fed only fish oil and desaturation exceeded oxidation by 3-fold in fish fed the diet containing 100% linseed oil. The molecular mechanisms underpinning these results were discussed

Rubus adenotrichus fruit extracts phytochemical characterization and antioxidant power evaluation for dermocosmetic formulations

There are more than 700 species of the genus Rubus, popularly known as Mora (tropical highland blackberry). In Costa Rica, the species Rubus adenotrichus has been characterized by its high content of antioxidant substances, becoming one of the most cultivated species and that may have characteristics to be used in cosmetics or medicine. The objective of the present study is to identify the main phytochemical groups and to quantify the main markers in order to associate them with cosmetic or medicinal functions in pharmaceutical products. Ripe fruits of Rubus adenotrichius were fractionated with solvents of low, medium and high polarity, followed by a phytochemical screening according to the World Health Organization Guidelines for the Control of Quality of Products of Natural Origin. The antioxidant properties were evaluated by means of the H-ORAC and DPPH test; the concentration of total phenols by Folin-Ciocalteau and antocinanins by differential pH was determined. Finally, the physicochemical properties of the aqueous extract, such as pH, specific gravity, Brix grades, conductivity, and osmolarity was determined and an absorption spectrum from 260 to 700 nm was obtained. Phenolic compounds were found as condensed and non-condensed tannins, anthocyanins, flavonoids, terpenes, and alkaloids as major phytochemical groups, a high antioxidant power measured in H-ORAC 311 ± 7.63 μg/mol Trolox Equivalent/g of dry fruit, and EC 50 118.46 mg/L for the aqueous extract. The total phenols found was 20.85 ± 0.27 mg/g of dry sample of gallic acid equivalents which makes the Rubus adenotrichus fruit an excellent component for bacteriostatic, anti-aging, anti-wrinkle, nourishing and moisturizing formulations, and the astringent effect also allows its application to small superficial wounds on the skin. Likewise, the acidic pH of 3.55 ± 0.1 is beneficial for maintaining the cutaneous acid mantle thereby favoring the normal flora of the skin, but may be a problem for the formulation of carbomer-based gels or the incorporation of preservatives. The aqueous extract is hyperosmotic (559.66 ± 3.21 mOs/kg) and has a high electrical conductivity (285 ± 2 μS/cm) due to the presence of electrolytes and a considerable amount of sugars, according to Brix degrees (7.543° ± 0.005°). Finally, the 4% w/w aqueous extract shows an absorption of ultraviolet radiation of 25% in the wavelengths from 260 to 400nm, by which it also could be useful for formulating compositions for sun protection.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones Farmacéuticas (INIFAR

Nutritional and environmental regulation of the synthesis of highly unsaturated fatty acids and of fatty-acid oxidation in Atlantic salmon (Salmo salar L.) enterocytes and hepatocytes

The aim was to determine if highly unsaturated fatty acid (HUFA) synthesis and fatty acid oxidation in Atlantic salmon (Salmo salar L.) intestine was under environmental and/or seasonal regulation. Triplicate groups of salmon were grown through a full two-year cycle on two diets containing either fish oil (FO), or a diet with 75% of the FO replaced by a vegetable oil (VO) blend containing rapeseed, palm and linseed oils. At key points in the life cycle, fatty acyl desaturation/elongation (HUFA synthesis) and oxidation activities were determined in enterocytes and hepatocytes using [1-14C]18:3n-3 as substrate. As observed previously, HUFA synthesis in hepatocytes showed peak activity at seawater transfer and declined thereafter, with activity consistently greater in fish fed the VO diet. In fish fed FO, HUFA synthesis in enterocytes in the freshwater stage was at a similar level to that in hepatocytes. However, HUFA synthesis in enterocytes increased rapidly after seawater transfer and remained high for some months after transfer before decreasing to levels that were again similar to those observed in hepatocytes. Generally, enterocyte HUFA synthesis was higher in fish fed the VO diet compared to the FO diet. Oxidation of [1-14C]18:3n-3 in hepatocytes from fish fed FO tended to decrease during the freshwater phase but then increased steeply, peaking just after transfer before decreasing during the remaining seawater phase. At the peak in oxidation activity around seawater transfer, activity was significantly lower in fish fed VO compared to fish fed FO. In enterocytes, oxidation of [1-14C]18:3 in fish fed FO showed a peak in activity just prior to seawater transfer. In fish fed VO, other than high activity at 9 months, the pattern was similar to that obtained in enterocytes from fish fed FO with a high activity around seawater transfer and declining activity in seawater. In conclusion, fatty acid metabolism in intestinal cells appeared to be under dual nutritional and environmental or seasonal regulation. The temporal patterns for fatty acid oxidation were generally similar in the two cell types, but HUFA synthesis in enterocytes peaked over the summer seawater phase rather than at transfer, as with hepatocytes, suggesting possibly different regulatory cues

Memoria del II Coloquio Internacional sobre Diversidad Cultural y Estudios Regionales

Desde la Sede de Occidente y, específicamente, en el seno de la Coordinación de Investigación y con el apoyo de la Dirección de la Sede y las Coordinaciones de Docencia, Administración y Acción Social, así como de la Vicerrectoría de Investigación, se han celebrado en el 2011 y en el 2012 dos coloquios internacionales sobre diversidad cultural y estudios regionales. El propósito de ambos consistió principalmente en motivar a investigadores e investigadoras de las distintas unidades académicas de la Universidad de Costa Rica y de otras instituciones de Educación Superior, así como a representantes de Centros e Institutos de Investigación nacionales e internacionales, a presentar resultados de investigaciones que contribuyeran a un mayor conocimiento de los procesos culturales y que dieran a conocer resultados que permitieran la comprensión de las realidades de distintos sectores y regiones. En el 2011 se presentaron cuarenta y seis ponencias y se dictaron tres conferencias magistrales, y en el 2012 se expusieron cincuenta ponencias y se impartieron tres conferencias magistrales.UCR::Sedes Regionales::Sede de Occidente::Recinto San Ramón::Centro de Investigaciones sobre Diversidad Cultural y Estudios Regionales (CIDICER

Hipo persistente de 10 años de evolución

Sin financiaciónNo data (2017)UE