Caiman's fat enriched with n-3 fatty acids: potential food supplement.

Broad-snouted caiman (Caiman latirostris) products (meat, fat and oil) are currently beginning to be valued as a food of special interest due to its high content of n-3 fatty acids. Thus, the objective of this study was to characterize the fats of caiman fed with diets enriched with flaxseeds (Linus usitatissimun) rich in n-3 fatty acids, lignans and antioxidants. Caimans were fed six days a week with: a control diet (C), and a diet enriched with ground flaxseed = 90% C + 10% flaxseed ground (FS), during 30 (FS30) and 60 (FS60) days. Animals fed the flaxseed-enriched diets increased linolenic acid content and reduced the n-6/n-3 ratio of fats relative to controls, and this improvement increased over time. The proportion of eicosapentaenoic acid also increased, but there was no difference at the time the enriched diets were offered. Caiman fat of the FS30 and FS60, showed a decrease in lipoperoxidation (24% and 40%) and reactive oxygen species (44% and 76%) accompanied by an increase in antioxidant systems. Consumption of a flax-enriched diet by caimans increases the content of essential fatty acids and improves the lipoperoxidative status of fat. This provides an enriched fat with potential for the development products for human consumption.

Enriched functional milk fat ameliorates glucose intolerance and triacylglycerol accumulation in skeletal muscle of rats fed high-fat diets.

PURPOSE: We examined the effect of a functional milk fat (FMF) on the glucose metabolism and its association with the intramuscular triacylglycerol (TAG) content in rats fed high-fat diets. METHODS: Male Wistar rats were fed for 60 days with S7 (soybean oil 7%), S30 (soybean oil 30%), MF30 (soybean oil 3% + milk fat 27%), or FMF30 (soybean oil 3% + FMF 27%) diets. An oral glucose tolerance test was performed. The levels of key metabolites in gastrocnemius muscle and mRNA levels of genes involved in glucose and lipid metabolism in muscle, epididymal white adipose tissue (EWAT), and serum were assessed. RESULTS: The S30 diet induced glucose intolerance and led to TAG, citrate, and glucose accumulation in muscle. Moreover, we observed a downregulation of uncoupling proteins (Ucp2 and Ucp3) and insulin receptor substrate-1 (Irs1) genes, lower carnitine palmitoyl transferase-1b (CPT-1b), and phosphofructokinase-1 (PFK1) activities in muscle and lower expression of adiponectin (Adipoq) in EWAT. The FMF30 diet ameliorated the glucose intolerance and normalized the glucose and TAG levels in muscle, preventing the accumulation of citrate and enhancing glucose utilization by the PFK1. The beneficial effects might also be related to the higher expression of Adipoq in EWAT, its receptor in muscle (Adipor1), and the expression of Ucp2, Ucp3, and Irs1 in muscle, restoring the alterations observed with the S30 diet. CONCLUSIONS: FMF30 modulated key genes involved in glucose and lipid metabolism in skeletal muscle, improving the glucose utilization and preventing TAG, glucose, and citrate accumulation.

Effect of flaxseed and flaxseed oil supplemented in caiman diet on meat fatty acids.

Increasing polyunsaturated or long-chain fatty acids in meat for human consumption improves both nutritional quality and consumer perception. The increase could occur through the addition of rich sources of omega-3 fatty acids (such as flaxseed or flaxseed oil) to the animal diet. The aim of this study was to evaluate the effects of dietary supplement with two presentations of flax (crushed seeds or oil) on the change of FA content in two cuts of caiman meat (tail and neck). We measured fatty profile in two different caiman meat cuts (neck and tail) from 30 animals (total length 96.7 ± 4.9 cm, snout-vent length 47.8 ± 3 cm, weight 4.2 ± 0.6 kg), raised in individual enclosures, fed three a week for 50 days with crushed chicken head and a dry food formulated for these reptiles in a 70/30 ratio (C, n = 10), control diet with 10% crushed flaxseed (FS, n = 10), and control diet with 10% flaxseed oil (FO, n = 10), while the remaining days animals were fed the control diet. Meats from animals fed both enrichment diet (FS and FO) showed an increase of C18:3n-3 and ΣUFA with respect to control diet. Although both enriched diets raised the levels of C18:3n-3, the neck showed higher values than the tail. We observed that the neck is more susceptible than the tail to be improved by FO, which could suggest that it is more beneficial to consume neck meat. In order to be implemented in caiman farms, flaxseed oil is more expensive than seed, but more effective, easier to manage, and is practical for application on caiman farms.

Functional milk fat enriched in conjugated linoleic acid prevented liver lipid accumulation induced by a high-fat diet in male rats.

The aim was to investigate the potential effect of functional milk fat (FMF), naturally enriched in conjugated linoleic acid, on the prevention of liver lipid accumulation and some biochemical mechanisms involved in the liver triacylglycerol (TAG) regulation in high-fat (HF) fed rats. Male Wistar rats were fed (60 days) with S7 (soybean oil, 7%) or HF diets: S30 (soybean oil, 30%), MF30 (soybean oil, 3% + milk fat -MF-, 27%) or FMF30 (soybean oil, 3% + FMF, 27%). Nutritional parameters, hepatic fatty acid (FA) composition, liver and serum TAG levels, hepatic TAG secretion rate (TAG-SR), lipoprotein lipase (LPL) activity in adipose tissue and muscle, activities and/or mRNA levels of lipogenic and ß-oxidative enzymes, and mRNA levels of transcription factors and FA transport proteins were assessed. The hepatic lipid accumulation induced by the S30 diet was associated with increased mRNA levels of FA transporters; and it was prevented by FMF through an increase in the hepatic TAG-SR, carnitine palmitoyltransferase-1a activity and peroxisome proliferator-activated receptor alpha mRNA levels, as well as by a reduction of the mRNA levels of FA transporters. The hypotriacylglyceridaemia observed in S30 was related with an increased LPL activity in adipose tissue and it was reverted by FMF through the increased hepatic TAG-SR. In brief, FMF prevented the liver lipid accumulation induced by HF diets by increasing the hepatic TAG-SR and ß-oxidation, and reducing the hepatic FA uptake. The increased hepatic TAG-SR induced by FMF could be responsible for the attenuation of serum TAG alterations.

Maternal conjugated linoleic acid consumption prevented TAG alterations induced by a high-fat diet in male adult rat offspring.

Maternal nutritional programming by a high-fat (HF) diet is related to hepatic lipid accumulation and steatosis in offspring. Conjugated linoleic acid (CLA) might ameliorate impaired hepatic lipid homoeostasis; therefore, the aim was to investigate the potential preventive effect of maternal CLA consumption on TAG metabolism alterations induced by HF diets in adult male rat offspring receiving or not receiving CLA. Female Wistar rats were fed a control (C) diet, HF diet or HF diet supplemented with CLA (HF+CLA) for 4 weeks before mating and throughout pregnancy and lactation. After weaning, for 9 weeks, male offspring of C or HF rats continued with the same diets as their mothers (C/C or HF/HF groups, respectively) and male offspring of HF+CLA rats were fed HF or HF+CLA diets (HF+CLA/HF or HF+CLA/HF+CLA groups, respectively). Nutritional parameters, serum and liver TAG levels, the TAG secretion rate (TAG-SR) and the activities as well as gene expression of key hepatic enzymes involved in TAG regulation were assessed. The most interesting results were that maternal CLA decreased epididymal white adipose tissue weight and prevented serum and liver TAG accumulation induced by a HF diet in adult male offspring receiving or not receiving CLA. The prevention of liver steatosis in HF+CLA/HF+CLA and HF+CLA/HF offspring was associated with an increased hepatic TAG-SR. Overall, this study provides evidence that maternal CLA consumption programmes TAG regulation and in this way contributes to lowering lipid levels in tissues and preventing liver steatosis in particular.

Maternal conjugated linoleic acid modulates TAG metabolism in adult rat offspring.

Conjugated linoleic acid (CLA) might regulate the lipid depots in liver and adipose tissue. As there is an association between maternal nutrition, fat depots and risk of offspring chronic disease, the aim was to investigate the effect of maternal CLA consumption on TAG regulation and some inflammatory parameters in adult male rat offspring receiving or not receiving CLA. Female Wistar rats were fed control (C) or CLA-supplemented (1 %, w/w) diets during 4 weeks before and throughout pregnancy and lactation. After weaning, male offspring of CLA rats were fed C or CLA diets (CLA/C and CLA/CLA groups, respectively), whereas C male rat offspring were fed a C diet (C/C group) for 9 weeks. Serum TAG levels were increased in the CLA/CLA and CLA/C groups, associated with a reduction of lipoprotein lipase activity and weights of adipose tissue. The liver TAG levels were decreased in the CLA/CLA group, related to a significant reduction of fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC) and glucose-6-phosphate dehydrogenase enzyme activities, as well as to the mRNA levels of FAS, ACC, stearoyl-CoA desaturase-1 and sterol regulatory element-binding protein-1c. Even though normal TAG levels were found in the liver of CLA/C rats, a reduction of lipogenesis was also observed. Thus, these results demonstrated a programming effect of CLA on the lipid metabolic pathways leading to a preventive effect on the TAG accretion in adipose tissue and the liver of male rat offspring. This knowledge could be important to develop some dietary strategies leading to a reduced incidence of obesity and fatty acid liver disease in humans.

N-3 fatty acids reduced trans fatty acids retention and increased docosahexaenoic acid levels in the brain.

INTRODUCTION: The levels of docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) are critical for the normal structure and function of the brain. Trans fatty acids (TFA) and the source of the dietary fatty acids (FA) interfere with long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis. OBJECTIVES: The aim of this study was to investigate the effect of TFA supplementation in diets containing different proportions of n-9, n-6, and n-3 FA on the brain FA profile, including the retention of TFA, LC-PUFA levels, and n-6/n-3 PUFA ratios. These parameters were also investigated in the liver, considering that LC-PUFA are mainly bioconverted from their dietary precursors in this tissue and transported by serum to the brain. Also, stearoyl-CoA desaturase-1 (SCD1) and sterol regulatory element-binding protein-1c (SREBP-1c) gene expressions were evaluated. METHODS: Male CF1 mice were fed (16 weeks) diets containing different oils (olive, corn, and rapeseed) with distinct proportions of n-9, n-6, and n-3 FA (55.2/17.2/0.7, 32.0/51.3/0.9, and 61.1/18.4/8.6), respectively, substituted or not with 0.75% of TFA. FA composition of the brain, liver, and serum was assessed by gas chromatography. RESULTS: TFA were incorporated into, and therefore retained in the brain, liver, and serum. However, the magnitude of retention was dependent on the tissue and type of isomer. In the brain, total TFA retention was lower than 1% in all diets. DISCUSSION: Dietary n-3 PUFA decreased TFA retention and increased DHA accretion in the brain. The results underscore the importance of the type of dietary FA on the retention of TFA in the brain and also on the changes of the FA profile.

The effects of trans-fatty acids on TAG regulation in mice depend on dietary unsaturated fatty acids.

The aim of this study was to investigate the effects of trans-fatty acids (TFA) on liver and serum TAG regulation in mice fed diets containing different proportions of n-3, n-6 and n-9 unsaturated fatty acids (UFA) from olive (O), maize (C) or rapeseed (R) oils partially substituted or not with TFA (Ot, Ct and Rt, respectively). Male CF1 mice were fed (30 d) one of these diets. The effects of the partial substitution (1 %, w/w) of different UFA with TFA on the activity and expression of hepatic enzymes involved in lipogenesis and fatty acids oxidation were evaluated, as well as their transcription factor expressions. Some of the mechanisms involved in the serum TAG regulation, hepatic VLDL rich in TAG (VLDL-TAG) secretion rate and lipoprotein lipase (LPL) activity were assessed. In liver, TFA induced an increase in TAG content in the Ot and Rt groups, and this effect was associated with an imbalance between lipogenesis and ß-oxidation. In the Ot group, exacerbated lipogenesis may be one of the mechanisms responsible for the liver steatosis induced by TFA, whereas in Rt it has been related to a decreased ß-oxidation, compared with their respective controls. The enhanced hepatic VLDL-TAG secretion in the Ot and Rt groups was compensated with a differential removal of TAG by LPL enzyme in extrahepatic tissues, leading to unchanged serum TAG levels. In brief, the effects of low levels of TFA on liver and serum TAG regulation in mice depend on the dietary proportions of n-3, n-6 and n-9 UFA.

TRANS FATTY ACIDS MODIFY NUTRITIONAL PARAMETERS AND TRIACYLGLYCEROL METABOLISM IN RATS: DIFFERENTIAL EFFECTS AT RECOMMENDED AND HIGH-FAT LEVELS.

INTRODUCTION: there is still little evidence on the metabolic trans fatty acids (TFA) effects at recommended fat levels. OBJECTIVE: to investigate the differential TFA effects on some nutritional parameters, TFA retention, and triacylglycerol (TAG) regulation in rats fed recommended and high-fat diets. METHODS: male Wistar rats were fed (30 days) diets containing recommended (7%,w/w) or high-fat (20%,w/w) levels, supplemented or not with TFA (C7, C20, TFA7 and TFA20). RESULTS: TFA7 (vs.C7) rats showed an increased body weight associated with higher fat pads and liver and serum TAG. The hypertriacylglyceridaemia was related to a decreased muscle LPL activity, while the higher hepatic TAG content was associated with both an increased SREBP-1c gene expression and ACC activity, and a reduced CPT-Ia gene expression. The TFA20 diet did not potentiate the higher body weight, fat pads and TAG levels induced by the C20 diet. Although the hepatic TAG-secretion rate (TAG-SR) increased by TFA20 vs. C20, the same triacylglyceridaemia was associated with a compensatory increase of the adipose tissue LPL activity. The attenuated hepatic TAG accretion in TFA20 was related to an increase of TAG-SR and to a lower increase of SREBP-1c and SCD1 mRNA expressions, paralleled to a relative decrease of SCD1 index and ACC activity. DISCUSSION AND CONCLUSION: TFA alters nutritional parameters and lipid metabolism in rats. However, different responses to the TFA on TAG levels and their regulation were observed between rats fed recommended and high-fat diets. These divergences might be related to different tissue TFA retentions and rumenic acid bioconversion.

Introducción: existen escasas evidencias sobre los efectos metabólicos de los AGT a niveles recomendados de grasa. Objetivo: investigar los efectos diferenciales de los ácidos grasos trans (TFA) sobre parámetros nutricionales, retención de TFA y regulación de triacilglicéridos (TAG) en ratas alimentadas con niveles recomendados o elevados de grasa. Métodos: ratas macho Wistar fueron alimentadas (30 días) con dietas que contenían un 7% o 20% de grasas suplementadas o no con TFA (C7-C20-TFA7-TFA20). Resultados: TFA7 (vs. C7) incrementó el peso corporal asociado a mayores panículos adiposos y TAG. La hipertriacilgliceridemia fue relacionada con una menor actividad LPL muscular, y el incrementado TAG hepático con una elevada expresión génica de SREBP-1c y actividad ACC, y reducida expresión génica de CPT-Ia. Los TFA no potenciaron los elevados pesos corporales, los panículos adiposos y los TAG inducidos por C20. Aunque la secreción hepática de TAG (TAG-SR) incrementó en TFA20 vs. C20, la similar triacilgliceridemia fue asociada a un compensatorio incremento de la actividad LPL en tejido adiposo. La atenuada acumulación hepática de TAG en TFA20 estuvo relacionada con una incrementada TAG-SR y un menor incremento de la expresión génica de SREBP-1c y SCD1, paralela a un relativo descenso del índice SCD1 y de la actividad ACC. Discusión y conclusión: los TFA alteran los parámetros nutricionales y lipídicos en ratas. Sin embargo, diferentes respuestas sobre los niveles y regulación de los TAG por los TFA fueron observadas entre ratas alimentadas con niveles recomendados y elevados de grasa dietaria. Estas divergencias pueden estar relacionadas con diferentes retenciones de TFA y su bioconversión a ácido ruménico.

Trans fatty acids modify nutritional parameters and triacylglycerol metabolism in rats: differential effects at recommended and high-fat levels / Los ácidos grasos trans modifican parámetros nutricionales y el metabolismo de triacilglicéridos en ratas: efectos diferenciales a niveles recomendados y elevados de grasa

Introduction: there is still little evidence on the metabolic trans fatty acids (TFA) effects at recommended fat levels. Objective: to investigate the differential TFA effects on some nutritional parameters, TFA retention, and triacylglycerol (TAG) regulation in rats fed recommended and high-fat diets. Methods: male Wistar rats were fed (30 days) diets containing recommended (7%,w/w) or high-fat (20%,w/w) levels, supplemented or not with TFA (C7, C20, TFA7 and TFA20). Results: TFA7 (vs.C7) rats showed an increased body weight associated with higher fat pads and liver and serum TAG. The hypertriacylglyceridaemia was related to a decreased muscle LPL activity, while the higher hepatic TAG content was associated with both an increased SREBP-1c gene expression and ACC activity, and a reduced CPT-Ia gene expression. The TFA20 diet did not potentiate the higher body weight, fat pads and TAG levels induced by the C20 diet. Although the hepatic TAG-secretion rate (TAG-SR) increased by TFA20 vs. C20, the same triacylglyceridaemia was associated with a compensatory increase of the adipose tissue LPL activity. The attenuated hepatic TAG accretion in TFA20 was related to an increase of TAG-SR and to a lower increase of SREBP-1c and SCD1 mRNA expressions, paralleled to a relative decrease of SCD1 index and ACC activity. Discussion and conclusion: TFA alters nutritional parameters and lipid metabolism in rats. However, different responses to the TFA on TAG levels and their regulation were observed between rats fed recommended and high-fat diets. These divergences might be related to different tissue TFA retentions and rumenic acid bioconversion (AU)

Introducción: existen escasas evidencias sobre los efectos metabólicos de los AGT a niveles recomendados de grasa. Objetivo: investigar los efectos diferenciales de los ácidos grasos trans (TFA) sobre parámetros nutricionales, retención de TFA y regulación de triacilglicéridos (TAG) en ratas alimentadas con niveles recomendados o elevados de grasa. Métodos: ratas macho Wistar fueron alimentadas (30 días) con dietas que contenían un 7% o 20% de grasas suplementadas o no con TFA (C7-C20-TFA7-TFA20). Resultados: TFA7 (vs. C7) incrementó el peso corporal asociado a mayores panículos adiposos y TAG. La hipertriacilgliceridemia fue relacionada con una menor actividad LPL muscular, y el incrementado TAG hepático con una elevada expresión génica de SREBP-1c y actividad ACC, y reducida expresión génica de CPT-Ia. Los TFA no potenciaron los elevados pesos corporales, los panículos adiposos y los TAG inducidos por C20. Aunque la secreción hepática de TAG (TAG-SR) incrementó en TFA20 vs. C20, la similar triacilgliceridemia fue asociada a un compensatorio incremento de la actividad LPL en tejido adiposo. La atenuada acumulación hepática de TAG en TFA20 estuvo relacionada con una incrementada TAG-SR y un menor incremento de la expresión génica de SREBP-1c y SCD1, paralela a un relativo descenso del índice SCD1 y de la actividad ACC. Discusión y conclusión: los TFA alteran los parámetros nutricionales y lipídicos en ratas. Sin embargo, diferentes respuestas sobre los niveles y regulación de los TAG por los TFA fueron observadas entre ratas alimentadas con niveles recomendados y elevados de grasa dietaria. Estas divergencias pueden estar relacionadas con diferentes retenciones de TFA y su bioconversión a ácido ruménico (AU)