Relación entre el nivel de grasa e ingestión y la excreción urinaria de nitrógeno y energía, en gazapos en crecimiento-cebo

Se determinó la excreción urinaria de nitrógeno (NU, %) y de energía (EU, kcal/100g), en la última semana de vida, de 36 conejos alimentados, desde el destete (a los 28 d) hasta el sacrificio a los dos meses de edad, con tres piensos conteniendo 0, 3 y 6 % de grasa añadida (G0, G3 y G6); y administrados a dos niveles de ingestión: ad libitum (IL) y restringido (IR) al 70 % de IL. El NU y la EU estuvieron influidos positivamente tanto por el nivel de ingestión (P<0,001) como por el % de grasa ingerida (P<0,05). En estos resultados puede estar involucrado el metabolismo tan elevado de las lipoproteínas transportadoras de lípidos, implicadas en el metabolismo de las grasas, ya sean de origen alimentario o de la lipogénesis de novo. La relación entre la EU y el NU aporta valores muy superiores a los que podría corresponder a las materias orgánicas nitrogenadas, por lo que se podría pensar, como posible causa, en la intervención de materia orgánica no nitrogenada. Asimismo, la cuantificación de la EM del pienso se ve afectada por el incremento del valor calórico de la orina, con el nivel de ingestión y/o el 6 % de grasa añadida. Con ello se evidencia la desigualdad entre ED y EM de la grasa en las raciones que las incluya. Asimismo, el hecho de que la movilización grasa —bien sea de origen alimentario o de la lipogénesis— altere la excreción nitrogenada y/o energética a través de la orina, pone de manifiesto la importancia de su consideración, especialmente cuando dicha pérdida puede afectar a los rendimientos de algunas producciones animales.Energy (EU, kcal/100g) and nitrogen (NU, %) urinary excretion were determined, during the week prior to slaughter, in an experiment carried out with 36 rabbits fed from weaning (28 d of age) to two months of age. Three diets were utilized consisting of: 0 %, 3 % and 6 % fat (G0, G3 and G6); and two levels of intake: ad libitum (IL) and restricted to 70 % of IL (IR). Both NU and EU were incremented by level of feed intake (P < 0.001) and fat level (P < 0.05) in the diet. These increment can be explained by the high metabolism of the remnant lipoprotein particles lipids transporters implied in the metabolism of the fats. The relationship between the EU and the NU contributes with high values to those that it could correspond to the nitrogen organic matters (NOM), that would be thought as a possible cause to the intervention of non NOM. Likewise, dietary metabolizable energy (ME) was affected by the increased caloric content in the urine, in the fattening diets, mainly in the IL. Fat metabolism affected urinary excretion of N, thus suggesting that when fat is added to the diet, this effect should be taken into consideration

Dietary erythrodiol modifies hepatic transcriptome in mice in a sex and dose-dependent way

Erythrodiol is a terpenic compound found in a large number of plants. To test the hypotheses that its long-term administration may influence hepatic transcriptome and this could be influenced by the presence of APOA1-containing high-density lipoproteins (HDL), Western diets containing 0.01% of erythrodiol (10 mg/kg dose) were provided to Apoe-and Apoa1-deficient mice. Hepatic RNA-sequencing was carried out in male Apoe-deficient mice fed purified Western diets differing in the erythrodiol content. The administration of this compound significantly up-regulated 68 and down-regulated 124 genes at the level of 2-fold change. These genes belonged to detoxification processes, protein metabolism and nucleic acid related metabolites. Gene expression changes of 21 selected transcripts were verified by RT-qPCR. Ccl19-ps2, Cyp2b10, Rbm14-rbm4, Sec61g, Tmem81, Prtn3, Amy2a5, Cyp2b9 and Mup1 showed significant changes by erythrodiol administration. When Cyp2b10, Dmbt1, Cyp2b13, Prtn3 and Cyp2b9 were analyzed in female Apoe-deficient mice, no change was observed. Likewise, no significant variation was observed in Apoa1-or in Apoe-deficient mice receiving doses ranging from 0.5 to 5 mg/kg erythrodiol. Our results give evidence that erythrodiol exerts a hepatic transcriptional role, but this is selective in terms of sex and requires a threshold dose. Furthermore, it requires an APOA1-containing HDL

Dietary squalene increases high density lipoprotein-cholesterol and paraoxonase 1 and decreases oxidative stress in mice

Background and Purpose: Squalene, the main hydrocarbon in the unsaponifiable fraction of virgin olive oil, is involved in cholesterol synthesis and it has been reported to own antiatherosclerotic and antiesteatosic effects. However, the squalene’s role on lipid plasma parameters and the influence of genotype on this effect need to be addressed. Experimental Approaches: Three male mouse models (wild-type, Apoa1- and Apoe- deficient) were fed chow semisynthetic diets enriched in squalene to provide a dose of 1 g/kg during 11 weeks. After this period, their plasma parameters and lipoprotein profiles were analyzed. Key Results: Squalene administration at a dose of 1 g/kg showed decreased reactive oxygen species in lipoprotein fractions independently of the animal background and caused an specific increase in high density lipoprotein (HDL)-cholesterol levels, accompanied by an increase in phosphatidylcholine and paraoxonase 1 and no changes in apolipoproteins A1 and A4 in wild-type mice. In these mice, the cholesterol increase was due to its esterified form and associated with an increased hepatic expression of Lcat. These effects were not observed in absence of apolipoprotein A1. The increases in HDL- paraoxonase 1 were translated into decreased plasma malondialdehyde levels depending on the presence of Apolipoprotein A1. Conclusions and Implications: Dietary squalene promotes changes in HDL- cholesterol and paraoxonase 1 and decreases reactive oxygen species in lipoproteins and plasma malondialdehyde levels, providing new benefits of its intake that might contribute to explain the properties of virgin olive oil, although the phenotype related to apolipoproteins A1 and E may be particularly relevant

Caracterización del proceso de secado con aire caliente de piensos experimentales

Los piensos experimentales empleados en investigaciones biomédicas difieren considerablemente respecto a los comerciales; en este caso, se elaboran con ingredientes purificados (almidón, caseína, grasas, celulosa, etc.) y pueden estar suplementados con un determinado compuesto, droga o medicamento. Otra diferencia sustancial es su proceso de elaboración, en este caso, al ser “casero” debe añadirse agua a la harina para conseguir una masa homogénea, que pueda compactarse en pellets o gránulos y posteriormente secarse para eliminar el agua. En este estudio, se han elaborado dos tipos de piensos con ingredientes purificados, uno de control denominado Chow y otro, denominado West, basado en el anterior, pero con un 20% de grasa de palma añadida. Ambos piensos se suplementaron con escualeno (1% en masa). Los objetivos del trabajo han sido: (i) deducir el tiempo mínimo de secado necesario para alcanzar la humedad del sólido correspondiente a un valor de actividad de agua (aw) de 0,6, y (ii) evaluar la posible degradación del escualeno debido al tratamiento de secado de los piensos. Para ello, los piensos se sometieron a un tratamiento de secado con aire caliente en un túnel de bandejas en las que se variaron las condiciones de temperatura (50; 65 y 80 ºC) y velocidad de aire (0,60; 1,10 y 1,65 m/s). Para conocer la humedad de equilibrio que debían alcanzar los piensos durante el secado para conseguir la estabilidad microbiológica (aw =0,6), se determinó la isoterma de sorción sometiendo los piensos a unas condiciones de ambiente saturado (a 20 ºC) en presencia de soluciones de MgCl2, K2CO3, NaCl, Mg(NO3)2 y CuCl2, de humedad relativa conocida. El contenido de escualeno se determinó por cromatografía de gases y espectrometría de masas en muestras tomadas a la salida del túnel de secado. Las diferencias en la cantidad de agua y grasa entre ambos piensos originaron diferencias significativas en las curvas de secado entre piensos Chow y West, mientras que de las condiciones impuestas para el secado, solo la temperatura afectó significativamente al tiempo de secado necesario para alcanzar la humedad crítica, obteniéndose valores de 4,85a ± 0,45, 2,32b ± 0,21 y 1,69ab ± 0,25 horas para piensos Chow para temperaturas de 50, 65 y 80 ºC, respectivamente; para piensos West los tiempos de secado fueron de 21,0a ±1,90, 23,1a ±0,37 y 11,6b ±0,83 horas a 50, 65 y 80 ºC, respectivamente. No se ha observado ningún efecto significativo de la velocidad del aire. Las conclusiones más importantes deducidas del presente trabajo son las siguientes: (1) únicamente la temperatura de secado influyó de forma significativa en el tiempo necesario para alcanzar la humedad crítica y en el tiempo total de secado; (2) la diferencia en la composición entre ambos piensos provoca diferencias en las pautas de secado; y (3) la mayor concentración de grasa saturada del pienso West compensa parcialmente la pérdida de escualeno por efecto del secado en comparación con el pienso Chow.<br /

Thioredoxin Domain Containing 5 Suppression Elicits Serum Amyloid A-Containing High-Density Lipoproteins

Thioredoxin domain containing 5 (TXNDC5) is a protein disulfide isomerase involved in several diseases related to oxidative stress, energy metabolism and cellular inflammation. In a previous manuscript, a negative association between fatty liver development and hepatic Txndc5 expression was observed. To study the role of TXNDC5 in the liver, we generated Txndc5-deficient mice. The absence of the protein caused an increased metabolic need to gain weight along with a bigger and fatter liver. RNAseq was performed to elucidate the putative mechanisms, showing a substantial liver overexpression of serum amyloid genes (Saa1, Saa2) with no changes in hepatic protein, but discrete plasma augmentation by the gene inactivation. Higher levels of malonyldialdehyde, apolipoprotein A1 and platelet activating factor-aryl esterase activity were also found in serum from Txndc5-deficient mice. However, no difference in the distribution of high-density lipoproteins (HDL)-mayor components and SAA was found between groups, and even the reactive oxygen species decreased in HDL coming from Txndc5-deficient mice. These results confirm the relation of this gene with hepatic steatosis and with a fasting metabolic derive remedying an acute phase response. Likewise, they pose a new role in modulating the nature of HDL particles, and SAA-containing HDL particles are not particularly oxidized. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Proteomics and gene expression analyses of squalene-supplemented mice identify microsomal thioredoxin domain-containing protein 5 changes associated with hepatic steatosis

Squalene is an abundant hydrocarbon present in virgin olive oil. Previous studies showed that its administration decreased atherosclerosis and steatosis in male apoE-knock-out mice. To study its effects on microsomal proteins, 1 g/kg/day of squalene was administered to those mice. After 10 weeks, hepatic fat content was assessed and protein extracts of microsomal enriched fractions from control and squalene-treated animals were analyzed by 2D-DIGE. Spots exhibiting significant differences were identified by peptide fingerprinting and MSMS analysis. Squalene administration modified the expression of thirty-one proteins involved in different metabolic functions and increased the levels of those involved in vesicle transport, protein folding and redox status. Only mRNA levels of 9 genes (Arg1, Atp5b, Cat, Hyou1, Nipsnap1, Pcca, Pcx, Pyroxd2, and Txndc5) paralleled these findings. No such mRNA changes were observed in wild-type mice receiving squalene. Thioredoxin domain-containing protein 5 (TXNDC5) protein and mRNA levels were significantly associated with hepatic fat content in apoE-ko mice. These results suggest that squalene action may be executed through a complex regulation of microsomal proteins, both at the mRNA and post-transcriptional levels and the presence of apoE may change the outcome. Txndc5 reflects the anti-steatotic properties of squalene and the sensitivity to lipid accumulation

Hepatic subcellular distribution of squalene changes according to the experimental setting

Squalene is the main unsaponifiable component of virgin olive oil, the main source of dietary fat in Mediterranean diet, traditionally associated with a less frequency of cardiovascular diseases. In this study, two experimental approaches were used. In the first, New Zealand rabbits fed for 4 weeks with a chow diet enriched in 1% sunflower oil for the control group, and in 1% of sunflower oil and 0.5% squalene for the squalene group. In the second, APOE KO mice received either Western diet or Western diet enriched in 0.5% squalene for 11 weeks. In both studies, liver samples were obtained and analyzed for their squalene content by gas chromatography-mass spectrometry. Hepatic distribution of squalene was also characterized in isolated subcellular organelles. Our results show that dietary squalene accumulates in the liver and a differential distribution according to studied model. In this regard, rabbits accumulated in cytoplasm within small size vesicles, whose size was not big enough to be considered lipid droplets, rough endoplasmic reticulum, and nuclear and plasma membranes. On the contrary, mice accumulated in large lipid droplets, and smooth reticulum fractions in addition to nuclear and plasma membranes. These results show that the squalene cellular localization may change according to experimental setting and be a starting point to characterize the mechanisms involved in the protective action of dietary squalene in several pathologies

Dietary avian proteins are comparable to soybean proteins on the atherosclerosis development and fatty liver disease in apoe-deficient mice

Background and aim: The type and amount of dietary protein has become a topic of re-newed interest in light of their involvement in metabolic diseases, atherosclerosis and thrombosis. However, little attention has been devoted to the effect of avian proteins despite their wide human consumption. The aim was to investigate the influence of chicken and turkey as sources of protein compared with that of soybean on atherosclerosis and fatty liver disease. Methods and results: To this purpose, male and female Apoe-deficient were fed purified Western diets differing in their protein sources for 12 weeks. After this period, blood, liver, aortic tree and heart base samples were taken for analyses of plasma lipids and atherosclerosis. Plasma triglycerides, non-esterified fatty acids, esterified cholesterol levels and radical oxygen species in lipoproteins changed depending on the diet and sex. Females consuming the turkey protein-containing diet showed decreased athero-sclerotic foci, as evidenced by the en face atherosclerosis analyses. The presence of macrophages and smooth muscle cells in plaques were not modified, and no changes were observed in hepatic lipid droplets in the studied groups either. Paraoxonase activity was higher in the group consuming turkey protein without sex differences, but only in females, it was significantly associated with aor-tic lesion areas. Conclusions: Compared to soybean protein, the consumption of avian proteins depending on sex resulted in similar or lower atherosclerosis development and comparable hepatic steatosis. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

The calcium-Activated potassium channel KCa3.1 is an important modulator of hepatic injury

The calcium-Activated potassium channel KCa3.1 controls different cellular processes such as proliferation and volume homeostasis. We investigated the role of KCa3.1 in experimental and human liver fibrosis. KCa3.1 gene expression was investigated in healthy and injured human and rodent liver. Effect of genetic depletion and pharmacological inhibition of KCa3.1 was evaluated in mice during carbon tetrachloride induced hepatic fibrogenesis. Transcription, protein expression and localisation of KCa3.1 was analysed by reverse transcription polymerase chain reaction, Western blot and immunohistochemistry. Hemodynamic effects of KCa3.1 inhibition were investigated in bile duct-ligated and carbon tetrachloride intoxicated rats. In vitro experiments were performed in rat hepatic stellate cells and hepatocytes. KCa3.1 expression was increased in rodent and human liver fibrosis and was predominantly observed in the hepatocytes. Inhibition of KCa3.1 aggravated liver fibrosis during carbon tetrachloride challenge but did not change hemodynamic parameters in portal hypertensive rats. In vitro, KCa3.1 inhibition leads to increased hepatocyte apoptosis and DNA damage, whereas proliferation of hepatic stellate cells was stimulated by KCa3.1 inhibition. Our data identifies KCa3.1 channels as important modulators in hepatocellular homeostasis. In contrast to previous studies in vitro and other tissues this channel appears to be anti-fibrotic and protective during liver injury

Hepatic galectin-3 is associated with lipid droplet area in non-alcoholic steatohepatitis in a new swine model

Non-alcoholic fatty liver disease (NAFLD) is currently a growing epidemic disease that can lead to cirrhosis and hepatic cancer when it evolves into non-alcoholic steatohepatitis (NASH), a gap not well understood. To characterize this disease, pigs, considered to be one of the most similar to human experimental animal models, were used. To date, all swine-based settings have been carried out using rare predisposed breeds or long-term experiments. Herein, we fully describe a new experimental swine model for initial and reversible NASH using cross-bred animals fed on a high saturated fat, fructose, cholesterol, cholate, choline and methionine-deficient diet. To gain insight into the hepatic transcriptome that undergoes steatosis and steatohepatitis, we used RNA sequencing. This process significantly up-regulated 976 and down-regulated 209 genes mainly involved in cellular processes. Gene expression changes of 22 selected transcripts were verified by RT-qPCR. Lipid droplet area was positively associated with CD68, GPNMB, LGALS3, SLC51B and SPP1, and negatively with SQLE expressions. When these genes were tested in a second experiment of NASH reversion, LGALS3, SLC51B and SPP1 significantly decreased their expression. However, only LGALS3 was associated with lipid droplet areas. Our results suggest a role for LGALS3 in the transition of NAFLD to NASH