RESUMO
There is a growing interest to understand the capacity of farmed fish species to biosynthesise the physiologically important long-chain (≥C20) n-3 and n-6 polyunsaturated fatty acids (LC-PUFAs), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ARA), from their C18 PUFA precursors available in the diet. In fish, the LC-PUFA biosynthesis pathways involve sequential desaturation and elongation reactions from α-linolenic acid (ALA) and linoleic acid (LA), catalysed by fatty acyl desaturases (Fads) and elongation of very long-chain fatty acids (Elovl) proteins. Our current understanding of the grass carp (Ctenopharyngodon idella) LC-PUFA biosynthetic capacity is limited despite representing the most farmed finfish produced worldwide. To address this knowledge gap, this study first aimed at characterising molecularly and functionally three genes (fads2, elovl5 and elovl2) with putative roles in LC-PUFA biosynthesis. Using an in vitro yeast-based system, we found that grass carp Fads2 possesses ∆8 and ∆5 desaturase activities, with ∆6 ability to desaturase not only the C18 PUFA precursors (ALA and LA) but also 24:5n-3 to 24:6n-3, a key intermediate to obtain DHA through the "Sprecher pathway". Additionally, the Elovl5 showed capacity to elongate C18 and C20 PUFA substrates, whereas Elovl2 was more active over C20 and C22. Collectively, the molecular cloning and functional characterisation of fads2, elovl5 and elovl2 demonstrated that the grass carp has all the enzymatic activities required to obtain ARA, EPA and DHA from LA and ALA. Importantly, the hepatocytes incubated with radiolabelled fatty acids confirmed the yeast-based results and demonstrated that these enzymes are functionally active.
Assuntos
Carpas , Ácidos Graxos Dessaturases , Ácidos Graxos Insaturados , Animais , Carpas/genética , Carpas/metabolismo , Ácidos Docosa-Hexaenoicos/biossíntese , Ácido Eicosapentaenoico/biossíntese , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Elongases de Ácidos Graxos , Ácidos Graxos Insaturados/biossíntese , Saccharomyces cerevisiaeRESUMO
Macroalgae have been recently described as a potential ingredient for aquafeeds, exerting several physiological benefits. Grass carp (Ctenopharyngodon idella) is a freshwater species, which has been the major fish species produced in the world in the last years. In order to determine the potential use of macroalgal wracks in fish feeding, C. idella juveniles were fed with an extruded commercial diet (CD) or the CD supplemented with 7% of a wind dried-powder (1 mm) from either a multispecific macroalgal wrack (CD + MU7) or a monospecific macroalgal wrack (CD + MO7) obtained from Gran Canaria island (Spain) coasts. After 100 days of feeding, survival, fish weight, and body indexes were determined, and muscle, liver, and digestive tract samples were collected. The total antioxidant capacity of macroalgal wracks was analyzed by assesing the antioxidant defense response and digestive enzymes activity in fish. Finally, muscle proximate composition, lipid classes (LC), and fatty acid (FA) profiles were also studied. Our results suggest that dietary inclusion of macroalgal wracks does not have negative effects on growth, proximate, and lipid composition, antioxidative status, or digestive capacity of C. idella. In fact, both macroalgal wracks caused a general lower fat deposition, and the multispecific wrack enhanced catalase activity in the liver.
RESUMO
Fish vary in their ability to biosynthesise long-chain polyunsaturated fatty acids (LC-PUFA) depending upon the complement and function of key enzymes commonly known as fatty acyl desaturases and elongases. It has been reported in Solea senegalensis the existence of a Δ4 desaturase, enabling the biosynthesis of docosahexaenoic acid (DHA) from eicosapentaenoic acid (EPA), which can be modulated by the diet. The present study aims to evaluate the combined effects of the partial replacement of fish oil (FO) with vegetable oils and reduced environmental salinity in the fatty acid composition of relevant body compartments (muscle, hepatocytes and enterocytes), the enzymatic activity over α-linolenic acid (ALA) to form n-3 LC-PUFA through the incubation of isolated hepatocytes and enterocytes with [1-14C] 18:3 n-3, and the regulation of the S. senegalensis fads2 and elovl5 in the liver and intestine. The presence of radiolabelled products, including 18:4n-3, 20:4n-3 and EPA, provided compelling evidence that a complete pathway enabling the biosynthesis of EPA from ALA, establishing S. senegalensis, has at least one Fads2 with ∆6 activity. Dietary composition prevailed over salinity in regulating the expression of fads2, while salinity did so over dietary composition for elovl5. FO replacement enhanced the proportion of DHA in S. senegalensis muscle and the combination with 20 ppt salinity increased the amount of n-3 LC-PUFA in hepatocytes.
Assuntos
Gorduras na Dieta/metabolismo , Ecossistema , Ácidos Graxos Ômega-3/biossíntese , Óleos de Peixe/metabolismo , Linguados/metabolismo , Óleos de Plantas/metabolismo , Ração Animal , Animais , Aquicultura , Gorduras na Dieta/administração & dosagem , Enterócitos/metabolismo , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Elongases de Ácidos Graxos/genética , Elongases de Ácidos Graxos/metabolismo , Óleos de Peixe/administração & dosagem , Hepatócitos/metabolismo , Músculos/metabolismo , Óleos de Plantas/administração & dosagem , Salinidade , Fatores de Tempo , Água/químicaRESUMO
Type 2 diabetes mellitus represents 30-50% of the cases of end stage renal disease worldwide. Thus, a correct evaluation of renal function in patients with diabetes is crucial to prevent or ameliorate diabetes-associated kidney disease. The reliability of formulas to estimate renal function is still unclear, in particular, those new equations based on cystatin-C or the combination of creatinine and cystatin-C. We aimed to assess the error of the available formulas to estimate glomerular filtration rate in diabetic patients. We evaluated the error of creatinine and/or cystatin-C based formulas in reflecting real renal function over a wide range of glomerular filtration rate (from advanced chronic kidney disease to hyperfiltration). The error of estimated glomerular filtration rate by any equation was common and wide averaging 30% of real renal function, and larger in patients with measured glomerular filtration rate below 60 mL/min. This led to chronic kidney disease stages misclassification in about 30% of the individuals and failed to detect 25% of the cases with hyperfiltration. Cystatin-C based formulas did not outperform creatinine based equations, and the reliability of more modern algorithms proved to be as poor as older equations. Formulas failed in reflecting renal function in type 2 diabetes mellitus. Caution is needed with the use of these formulas in patients with diabetes, a population at high risk for kidney disease. Whenever possible, the use of a gold standard method to measure renal function is recommended.
RESUMO
Objetivo: Se efectúa un estudio prospectivo para tratar de relacionar los parámetros antropométricos de la talla, el peso, el índice de masa corporal, así como la edad, con los patrones mamográficos obtenidos de las pacientes y obtener un perfil antropométrico. Material y método: Se realizó el estudio en 1.000 mujeres a las que se le efectuó una mamografía, en proyección cráneo-caudal y oblicua medio lateral de ambas mamas, independientemente que fuera de cribado o diagnóstica. Antes de la realización de la mamografía, se obtuvo el peso y la talla, realizados siempre por los mismos técnicos, y se les preguntó la talla de sujetador que usaban, para deducir el volumen mamario. Con los datos del peso y la talla se calculó el índice de masa corporal de Quetelet (peso/kg)/altura2 (m)).Después de leer la mamografía, se le asignó uno de los cuatro patrones mamográficos considerados en el BIRADS (Breast Imaging Reporting and Data System) establecido por el ACR (American College of Radiology): tipo I (graso), tipo II (densidades fibroglandulares dispersas), tipo III (densidades fibroglandulares distribuidas de forma heterogenea), tipo IV (denso). Se introdujeron los resultados en una base de datos del ordenador y se aplicó el programa estadístico SPSS 8.0, utilizando el modelo estadístico de regresión logística multivariante. Resultados: En las mujeres menores de 40 años, con normopeso, el patrón mamario denso supone el 67,8 por ciento y a medida que aumenta el índice de masa corporal (IMC) dicho patrón disminuye al 25,1 por ciento. El patrón graso es del 20 por ciento y a medida que aumenta el IMC, sube hasta al 80 por ciento. En las mujeres de 40 a 60 años, con peso normal, el patrón denso supone el 44 por ciento y disminuye hasta el 20,9 por ciento en las obesas grados II, III y IV; el patrón graso es el 11,1 por ciento y aumenta al 53,7 por ciento en las obesas grados II, III y IV. En las mujeres de más de 60 años con normopeso, el patrón denso supone el 19,3 por ciento y disminuye al 13 por ciento en las obesas grado III; el patrón graso es del 5,3 por ciento y asciende al 20,2 por ciento en el grado III de obesidad. Conclusiones: A mayor edad, mayor es la probabilidad de presentar un patrón mamográfico graso. A mayor IMC mayor es la probabilidad de presentar un patrón mamográfico graso. A mayor volumen mamario aumenta la probabilidad de presentar un patrón mamográfico graso (AU)