HL Diet Research Articles

High protein diets improve the growth of juvenile barramundi (Lates calcarifer) at elevated temperatures

Elevated temperatures and low aquatic oxygen levels are increasingly accompanying climate warming and can adversely affect the production and welfare of farmed fish. Both environmental factors and diet affect fish energetics. Still, little is known about the dietary effects on fish energetics at elevated temperatures and low aquatic oxygen levels and how that influences growth. Thus, a feeding trial was conducted to investigate the effect of two isoenergetic diets, high protein (HP, 57% crude protein and 9% total lipid) and high lipid (HL, 40% crude protein and 19% total lipid), on juvenile barramundi (Lates calcarifer, initial body mass: ∼ 3 g). Fish were acclimated for at least four weeks on the diets (three weeks at 35 °C) before measurements began (i.e.: measurements were taken between weeks four to six of the trial). Additionally, feed intake and maximum metabolic rate were tested under three levels of aquatic oxygen levels (normoxia >80, 60% and 30% air saturation). We found no significant dietary effect on feed intake, routine, maximum and postprandial peak metabolic rate. Gill ventilation rate was also unaffected by diet treatment. However, fish fed the HP diet had increased haematocrit and haemoglobin levels, improved growth rates, feed conversion ratio, and protein deposition relative to those fed the HL diet. Thus, this study demonstrated that a high protein diet enhanced key physiological traits such as oxygen-carrying capacity, potentially supporting improved juvenile barramundi growth at elevated temperatures.

Myo-inositol improves osmoregulation by promoting lipid utilization in Nile tilapia (Oreochromis niloticus)

This research explores the influence of myo-inositol (MI) on the hypertonic stress adaptation of Nile tilapia (Oreochromis niloticus) by increasing lipid utilization under long-term salinity stress. A two-factor interactive experiment was used, and diets containing either normal lipids (NL, 7%) or high lipids (HL, 15%) contained three MI concentrations of 0, 400, and 1200 mg/kg in each lipid diet. Fish were fed six diets under 20 psu (practical salinity units [psu]) for eight weeks. Under long-term hypertonic stress, dietary MI supplementation significantly improved the growth performance of O. niloticus (P < 0.05). Dietary 1200 mg/kg MI supplementation significantly promoted protein deposition and reduced fat accumulation in the whole fish (P < 0.05). The HL diet significantly caused lipid accumulation in the liver, while dietary 1200 mg/kg MI addition alleviated lipid accumulation by promoting the expression of genes related to lipolysis (PPAR-α; ATGL and CPT) and inhibiting the expression of genes related to lipid synthesis (SREBP; DGAT and FAS) (P < 0.05). In addition, 400 mg/kg MI significantly reduced serum lipids (TG and LDL-C) (P < 0.05). qPCR showed that the purity of dietary 1200 mg/kg MI significantly upregulated the expression of an ion transporter-related gene (NKA) in gills (P < 0.05). Meanwhile, 400 mg/kg and 1200 mg/kg MI significantly affected the content of fatty acids in the liver and gill (P < 0.05). In addition, dietary 1200 mg/kg MI supplementation significantly increased the antioxidant capacity in the liver of O. niloticus. In conclusion, dietary supplementation with 1200 mg/kg MI could regulate lipid metabolism, promote lipid utilization and improve the osmotic regulation ability of O. niloticus.

Feeding restriction unalters physiological responses to dietary lipid and carbohydrate levels in juvenile gibel carp (Carassius gibelio)

To investigate the physiological responses to different energy sources under feeding restriction in fish, gibel carp were fed a high lipid, low carbohydrate diet (HL diet, 12% lipid, 16% carbohydrate) or a high carbohydrate, low lipid diet (HC diet, 34% carbohydrate, 4% lipid) to satiation or 70% satiation (restriction) for 56 d; then, growth performance, nutrient metabolism, endoplasmic reticulum (ER) stress, autophagy, and apoptosis were determined. Fish that were fed the HL diet had higher final body weight, specific growth rate, and feed efficiency, lower phosphorylation levels of AKT and mTOR proteins and lower mRNA levels of gk than the HC group. When fed to 70% satiation, fish had lower feed intake, feeding rate, final body weight, and specific growth rate, and lower plasma glucose and nonesterified fatty acid levels. Feeding restriction induced the transcript level of gk and suppressed the mRNA level of acly, acc, fas. There were no significant differences in ER stress, autophagy and apoptosis between feeding levels or diets. Interactions between feeding level and diet were observed in plasma triglyceride level and the gene expression levels of fbpase and srebp1. Thus, gibel carp utilized HL diet better than HC diet, which was unalerted by feeding restriction.

Influence of Dietary Berberine on Liver Immune Response and Intestinal Health of Black Sea Bream (Acanthopagrus schlegelii) Fed with Normal and High-Lipid Diets

This study designed the normal diet (Con), high-lipid diet (HL), and 50 mg/kg berberine supplemented Con and HL diets (named as ConB and HLB, respectively). Fingerling black sea bream (Acanthopagrus schlegelii) (initial weight 1.47 ± 0.03 g) were fed these four diets for 8 weeks, and the liver immune response and intestinal health were evaluated. Fish fed the HL diet had the lowest serum glutathione peroxidase and catalase activities, while berberine supplementation significantly improved serum catalase activity ( P &lt; 0.05 ). The expressions of tumor necrosis factor-alpha (tnfα), nuclear factor-kappa b (nf-κb), and interleukin 1 beta (il-1β) were significantly increased by the HL diet, whereas berberine supplementation significantly downregulated these proinflammation cytokine expressions ( P &lt; 0.05 ). Berberine supplementation in normal and high-lipid diets significantly promoted hepatic anti-inflammation cytokines interleukin-10 (il-10) and transforming growth factor beta-1 (tgfβ-1) expressions ( P &lt; 0.05 ). The intestinal expressions of tnfα, nf-κb, and tgfβ-1 were not significantly influenced by different treatments, while Cu/Zn-superoxide dismutase (Cu/Zn-sod) expression was significantly upregulated in the ConB group compared with the Con group. High-lipid diet reduced intestinal villus length. the thickness of muscularis mucosa, mucosal folds, and diversity and richness of intestinal microbiota but increased numbers of goblet cells and width of lamina propria. Berberine supplementation in high-lipid diet alleviated these pathological changes and rebalanced intestinal microbiota composition. At the genus level, fish fed the HL diet had significantly lower abundances of some probiotics such as Lactobacillus and Hydrogenophaga than that of the HLB group ( P &lt; 0.05 ). In conclusion, berberine supplementation in high-lipid diet reduced liver inflammation, improved the antioxidative status of fish, and alleviated intestinal damage and intestinal microbiota alteration of black sea bream.

Effect of L-Hyp supplementation on collagen muscle histology, gene expression, growth performance, body composition and fillet texture on big size European sea bass (Dicentrarchux labrax)

Hydroxyproline (L-Hyp) is amply present in fishmeal but limited in plant-protein sources. This study was conducted to evaluate the effects of supplementation with dietary L-Hyp on the distribution of collagen types in the muscle, and on the texture, survival rate, growth rate, feed utilization, body composition as well as the expression of the gene that encodes the pro-alpha2 chains of type I collagen (Col Iα2) of large European sea bass (initial body weight 609.21 ± 75.39 g) from high plant-protein diets. Four isoproteic (42 % crude protein) and isolipidic (20 % crude lipid) experimental diets were formulated adding 0.6 (HL diet), 1.2 (HM diet), and 2% (HH diet) L-Hyp, respectively. Three periods of feeding of 45, 99 and 143 days were studied. L-Hyp supplementation at 1.2 % and 2 % significantly improved specific growth rate (SGR) and feed conversion ratio (FCR). In the white muscle, type I, IV collagen and trichromic stain were significantly higher in HH feed than the control diet. In the red muscle, only type I collagen was higher. HH diet, also increases Col Iα2 mRNA levels in muscle significantly. It can be concluded that the addition of crystalline l-Hyp at 1.2 % or 2 % in high plant-protein diets indicates positive effects on growth performance of adult European sea bass and increase in muscle total collagen deposition.

A metabolomics approach to investigate the proceedings of mitochondrial dysfunction in rats from prediabetes to diabetes.

BackgroundDiabetes mellitus (DM) is a leading cause of preventable cardiovascular disease, but the metabolic changes from prediabetes to diabetes have not been fully clarified. This study implemented a metabolomics profiling platform to investigate the variations of metabolites and to elucidate their global profiling from metabolic syndrome to DM. Methods: Male Sprague-Dawley rats (n = 44) were divided into four groups. Three groups were separately fed with a normal diet, a high-fructose diet (HF), or a high-fat (HL) diet while one group was treated with streptozotocin. The HF and HL diet were meant to induce insulin resistance, obesity, and dyslipidemia, which known to induce DM. Results: The most significant metabolic variations in the DM group’s urine samples were the reduced release of citric acid cycle intermediates, the increase in acylcarnitines, and the decrease in urea excretion, all of which indicated energy metabolism abnormalities and mitochondrial dysfunction. Overall, the metabolic analysis revealed tryptophan metabolic pathway variations in the prediabetic phase, even though the mitochondrial function remains unaffected. Conclusion: This study show that widespread methylations and impaired tryptophan metabolism occur in metabolic syndrome and are then followed by a decline in citric acid cycle intermediates, indicating mitochondrial dysfunction in diabetes.

Saturated Fatty Acid‐Enriched Diet Affect Liver Transcriptional Response of Anti‐oxidant Genes of Perinatal Undernourished Rats

In this work, we evaluated the impact of a saturated fatty acid (SFA)‐enriched diet (HL) in the post‐weaning offspring subjected to maternal protein restriction in liver genes of redox balance and inflammatory pathway. Wistar rats were mated and during gestation and lactation, mothers received control (C) or low protein diet (LP, 8% protein). After weaning, rats received either C or HL (+59% SFA) diets up to 90 days of life. It was verified that circulating markers of lipid metabolism and liver function were not significantly altered between groups. The LP group submitted to the post‐weaning HL diet showed an increase in liver protein and lipid oxidation (p&lt;0.01). This group also presented greater gene transcription of NF‐KB1 and TNF‐α (p&lt;0.05) compared to controls. Liver mRNA contents of pro‐oxidant enzymes (XDH, NOX1 and RAC1) were not different between LP and controls animals. Post‐weaning HL diet did not alter the pattern of expression of SOD1, SOD2, CAT, GPX1, GPX2, UCP2 genes in LP groups, except for CAT, which was significantly higher in LP group fed HL diet compared to C (+66%, p&lt;0.05). In protein level, CAT was lower in LP compared to control animals under both post‐weaning C and HL (p&lt;0.05). In contrast, SOD2 protein content was twice higher in LP groups (p&lt;0.05). However, GPX1/2 protein expression was similar between groups. Regarding transcription factors, no differences were noted in NRF2 and FOXO3 mRNA contents. However, SFA enhanced PGC1α (+207%, p&lt;0.05) and PPARγ (+151%, p&lt;0.05) levels in LP groups vs. C. Thus, our data suggest that SFA‐enriched diet induces oxidative stress, activation of inflammatory pathways, however without metabolic disturbance when the animals were submitted to a low protein diet during critical periods of development.Support or Funding InformationThis study was supported by FACEPE (Brazil), CNPq (Brazil) and CAPES/COFECUB (Brazil/France).

Diet composition modulates intestinal hydrolytic enzymes in white-footed mice (Peromyscus leucopus)

AbstractWe tested whether white-footed mice (Peromyscus leucopus) modulate the activity of three key intestinal digestive enzymes (maltase, sucrase, and aminopeptidase-N [APN]) based on diet composition. To test the adaptive modulation hypothesis (AMH), we fed mice either of three kinds of synthetic diet, high starch (HS, 50% carbohydrate), high protein (HP, 60% protein), and high lipid (HL, 25% lipid), and determined their digestive responses. First, there was no effect of either diet itself, or time eating the diet, on body mass, or mass and length of small intestine. Second, the activity of both disaccharidases summed over the entire small intestine was highest on the HS diet, which was higher than on the HP diet by about 45% and higher than on the HL diet by 400%. This was consistent with our prediction that starch induces disaccharidase activity, and demonstrated induction of disaccharidase activities by high dietary carbohydrate in a wild mammal. Third, both summed and mass-specific activity of maltase and sucrase of HL mice were lower than those of HP mice, even though their diets had the same content of starch, which suggests that lipid in the HL diet inhibited disaccharidase activity. Finally, the summed activity of APN was highest on the HP diet, which was higher than on the HS diet or HL diet by ~100%, consistent with our prediction that high protein content induces peptidase activity. Taken together, our results support the AMH, though they also illustrate that high lipid content in the diet can confound some predicted patterns. Flexibility of digestive enzyme activity is likely important in allowing white-footed mice to cope with fluctuations in the environmental availability of different food types.Probamos si el ratón de patas blancas (Peromyscus leucopus) modula las actividades de tres enzimas digestivas intestinales claves – maltasa, sacarasa y N-aminopeptidasa- al modificarse la composición de la dieta. Para someter a prueba la hipótesis de la modulación adaptativa, se alimentaron paralelamente ratones con tres tipos de dietas semi-sintéticas, una alta en almidón (HS, 50% carbohidratos), otra alta en proteína (HP, 60% proteínas), y una alta en lípidos (HL, 25% lípidos), y se determinaron sus respuestas digestivas. No se observó un efecto de la dieta o del tiempo que la consumieron sobre la masa corporal o la masa y el largo del intestino delgado (SI). La sumatoria de las actividades de cada una de las disacaridasas a lo largo de todo el intestino delgado fue más alta con la dieta HS que con las dietas HP y HL, un 45% y un 400% mayor, respectivamente. Esto fue consistente con nuestra predicción acerca de que el almidón induce la actividad disacaridásica, constituyendo el primer estudio que demuestra inequívocamente en un animal silvestre, que la inducción de las actividades de las disacaridasas intestinales es mediada por un incremento de los carbohidratos en la dieta. Las actividades hidrolíticas totales y masa-específicas de la maltasa y sacarasa de los ratones HL fueron más bajas que las de los alimentados con dieta HP, aun cuando sus dietas tenían el mismo contenido de almidón, lo que sugiere que los lípidos en la dieta HL inhiben la actividad de las disacaridasas. La actividad hidrolítica total de la N-aminopeptidasa fue mayor con la dieta HP, ~100% más alta que para las dietas HS y HL, de manera consistente con la predicción que propone que la presencia de mayor cantidad de proteína en la dieta induce la actividad peptidásica. En conjunto nuestros resultados dan soporte a la hipótesis de la modulación adaptativa, además de ilustrar que los lípidos en las dietas pueden confundir la predicción de patrones de procesamiento de alimentos. La flexibilidad de la actividad de las enzimas digestivas es probablemente importante para los ratones de patas blancas, ya que les permite adecuarse a las fluctuaciones ambientales de disponibilidad de diferentes tipos de recursos.

High-Fish Oil and High-Lard Diets Differently Affect Testicular Antioxidant Defense and Mitochondrial Fusion/Fission Balance in Male Wistar Rats: Potential Protective Effect of ω3 Polyunsaturated Fatty Acids Targeting Mitochondria Dynamics.

High-fat diets rich in fish oil (HFO diet, mainly ω3-PUFAs), in contrast to high-fat diets rich in lard (HL diet, mainly saturated fatty acids) have been shown to induce improvement in mitochondrial function and fusion processes associated with a reduction in reactive oxygen species production in both liver and skeletal muscle. High-fat diets may also impair testicular function, and mitochondria represent important cellular organelles with a pivotal role in reproductive function. Mitochondria are dynamic organelles that frequently undergo fission/fusion processes. A shift toward mitochondrial fusion process has been associated with improvement of mitochondrial function, as well as with ω3-PUFAs protective effects. The present study aimed to analyze the effect of chronic overfeeding (six weeks) with HFO or HL diet on testicular tissue histology, oxidative stress, antioxidant defenses, and mitochondrial fusion (mitofusin 2) and fission (dynamic related protein 1) protein. Our results showed that HFO diet induced less testicular histology impairment, oxidative stress, and apoptosis compared to a HL diet. This finding was associated with an increase in antioxidant activities and a shift toward mitochondrial fusion processes induced by HFO diet compared to HL diet, suggesting that ω3-PUFAs may act as bioactive compound targeting mitochondria dynamics to prevent testicular impairment.

Saturated Fatty Acid-Enriched Diet-Impaired Mitochondrial Bioenergetics in Liver From Undernourished Rats During Critical Periods of Development.

The nutritional transition that the western population has undergone is increasingly associated with chronic metabolic diseases. In this work, we evaluated a diet rich in saturated fatty acids (hyperlipidic, HL) after weaning of the offspring rats submitted to maternal protein restriction on the hepatic mitochondrial bioenergetics. Wistar rats were mated and during gestation and lactation, mothers received control diets (NP, normal protein content 17%) or low protein (LP, 8% protein). After weaning, rats received either NL (normolipidic) or HL (+59% SFA) diets up to 90 days of life. It was verified that all respiratory states of hepatic mitochondria showed a reduction in the LP group submitted to the post-weaning HL diet. This group also presented greater mitochondrial swelling compared to controls, potentiated after Ca2+ addition and prevented in the presence of EGTA (calcium chelator) and cyclosporin A (mitochondrial permeability transition pore inhibitor). There was also an increase in liver protein oxidation and lipid peroxidation and reduction in catalase and glutathione peroxidase activities in the LP group fed HL diet after weaning. Our data suggest that adult rats subjected to maternal protein restriction were more susceptible to hepatic mitochondrial damage caused by a diet rich in saturated fatty acids post-weaning.

A moderately high level of dietary lipid inhibited the protein secretion function of liver in juvenile tiger puffer Takifugu rubripes

Tiger puffer have a unique lipid storage pattern. They store lipid predominantly in liver. To investigate the hepatic physiology of tiger puffer in response to a moderately high level of dietary lipid, a 74-day feeding trial was conducted, followed by a hepatic transcriptome assay. Two experimental diets which had an optimal (10.44%, Control) or moderately higher (14.64%, high-lipid diet, HL) dietary lipid level was formulated. Each diet was fed to triplicate tanks. No significant difference was observed in growth and feed efficiency between the two groups, but the survival was significantly lower in group HL. The HL diet also resulted in significantly higher lipid accumulation in liver, which was reflected in the hepatic histology. The biochemical parameters in serum confirmed the existence of stress in liver caused by high lipid intake. A total of 63 differentially expressed genes between groups were observed in the hepatic transcriptome assay, which were primarily enriched in Gene Ontology (GO) terms such as Endopeptidase activity, Secretion, and Organic acid transport, as well as in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways such as Protein processing in endoplasmic reticulum and DNA replication. The HL diet tended to inhibit the protein synthesis and secretion in liver, and this was evidenced by activities/concentrations of selected proteins secreted into intestine. Genes related to liver protection and repair were transcriptionally stimulated by diet HL. In conclusion, compared to the optimal lipid requirement, a moderately higher lipid level in the diet for tiger puffer did not compromise the growth performance, but tended to inhibit the protein secretion function of liver and stimulate the processes related to liver protection and repair. The present results will be beneficial to both feed management in tiger puffer farming and elucidation of lipid metabolism characteristics in fish which store lipid in liver.

Effects of feeding with broiler litter in pellet-form diet on Qizil fattening lambs' performance, nutrient digestibility, blood metabolites and husbandry economics.

The aim of this study was to evaluate the feeding of Qizil fattening lambs with different levels of broiler litter (BL) on their weight gain, dry matter intake (DMI), nutrient digestibility, selected blood metabolites and husbandry economics. During an eight-weeks experimental period, 28 male lambs (an average of 42.21 ± 5.63 kg and ages of 7-8 months) were allocated randomly to one of four dietary treatments, including; control diet with no litter (NL, n = 7), diet containing 5% BL (LL, n = 7), diet with 10% BL (ML, n = 7) and diet containing 15.00% BL (HL, n = 7) as dry matter (DM) basis. The lambs were kept in individual pens and had free access to feed and water (ad libitum) throughout the study. In this research, DMI and feed conversion ratio were not influenced significantly by the dietary treatments, while average daily gain (ADG) was found to be significant. The lambs which consumed LL diet (5.00% BL) had the greatest ADG. The DM digestibility significantly influenced by dietary treatments, as the HL diet (15.00% BL) had the least DM digestibility. There were also significant differences in the crude protein and acid detergent fiber digestibility among the treatments. Blood urea nitrogen and glucose levels were significantly affected by the treatments. Low litter treatment had the least FCR and the highest economical advantage. In conclusion, feeding male Qizil lambs with BL can reduce production cost without any negative effects on performance.

Effect of Dietary Lipid Level and Feeding Frequency on the Growth, Feed Utilization, and Body Composition of Juvenile Spotted Seabass, Lateolabrax maculatus

AbstractA 6‐wk feeding trial was conducted to evaluate the effects of different dietary lipid levels and feeding frequencies on the growth performance, feed utilization, and body composition of juvenile spotted seabass, Lateolabrax maculatus. Two experimental diets were prepared with two different dietary lipid contents, low lipid (7%; LL) and high lipid (14%; HL). Each diet was fed to triplicate groups of fish (5.5 ± 0.01 g) to apparent satiation at three meals per day, two meals per day, one meal per day, and one meal every 2 d, respectively, for 6 wk. Fish growth performance in terms of weight gain (WG) and specific growth rate (SGR) was significantly affected by frequency of feeding, with increasing values as feeding frequency increased up to twice daily, regardless of dietary lipid content. In addition, fish fed the diet with the HL level (14%) showed significantly higher WG and SGR than those fed the LL diet (7%) at all the feeding frequencies tested. Feed efficiency (FE) and protein efficiency ratio (PER) were affected by both dietary lipid level and feeding frequency. FE and PER values were significantly higher in fish fed the HL diet and/or when fish were fed twice or thrice a day. However, daily feed intake and daily energy intake were significantly affected only by feeding frequency and were significantly reduced when the fish were fed only once every 2 d compared with those fed more frequently. Whole‐body moisture content of fish tended to decrease with increasing dietary lipid level and frequency of feeding. In contrast, whole‐body lipid content increased in fish as dietary lipid level and feeding frequency increased. Consequently, we can conclude that feeding spotted seabass twice daily to apparent satiation is acceptable and sufficient to achieve good growth and FE, as fish performance was not significantly enhanced when feeding was increased from two to three times daily.

Altered lipid partitioning and glucocorticoid availability in CBG-deficient male mice with diet-induced obesity.

To evaluate how deficiency in corticosteroid-binding globulin (CBG), the specific carrier of glucocorticoids, affects glucocorticoid availability and adipose tissue in obesity. C57BL/6 (WT) and CBG-deficient (KO) male mice were fed during 12 weeks with standard or hyperlipidic diet (HL). Glucocorticoid availability and metabolic parameters were assessed. Body weight and food intake were increased in KO compared with WT mice fed a standard diet and were similar when fed a HL diet. Expression of CBG was found in white adipose tissue by immunochemistry, real-time PCR, and Western blot. In obesity, the subcutaneous depot developed less in KO mice compared with WT, which was associated with a minor adipocyte area and peroxisome proliferator-activated receptor-γ expression. Conversely, the epididymal depot displayed higher weight and adipocyte area in KO than in WT mice. CBG deficiency caused a fall of hepatic 11β-hydroxysteroid dehydrogenase type 2 expression and an increase in epidymal adipose tissue, particularly in HL mice. Deficiency in CBG drives lipid partitioning from subcutaneous to visceral adipose depot under a context of lipid excess and differentially modulates 11β-hydroxysteroid dehydrogenase type 2 expression.

Effect of different diets on digestive enzyme activities, in vitro digestibility, and midgut gland structure in juvenile crayfish, Cherax quadricarinatus

AbstractThis study investigated the effects of food quality on digestive enzyme activities, in vitro protein digestibility and histological traits of the midgut gland in juvenile crayfish Cherax quadricarinatus. Animals of a wide weight range were fed different diets: two commercial diets with high or low lipid content (high lipid and low lipid, respectively) and were compared with a reference diet (RF) previously formulated for this species. Proteinase, lipase and amylase activities were significantly influenced by diet and weight. Specific trypsin activity was significantly higher for crayfish fed with the HL diet. Trypsin activity depended on diet and weight. Protein digestibility showed that HL was the most digestible diet and RF the least. The weight of the animals did not affect protein digestibility. Structural disorganization, hypertrophy of B‐cells and presence of large vacuoles in R‐cells were mainly observed in juveniles fed with HL, indicative of malnutrition. Thus, our data suggest that the HL diet would not be the most appropriate for C. quadricarinatus, while RF diet would be more convenient for culture of this species.

The ability of genetically lean or fat slow-growing chickens to synthesize and store lipids is not altered by the dietary energy source

The increasing use of unconventional feedstuffs in chicken’s diets results in the substitution of starch by lipids as the main dietary energy source. To evaluate the responses of genetically fat or lean chickens to these diets, males of two experimental lines divergently selected for abdominal fat content were fed isocaloric, isonitrogenous diets with either high lipid (80 g/kg), high fiber (64 g/kg) contents (HL), or low lipid (20 g/kg), low fiber (21 g/kg) contents (LL) from 22 to 63 days of age. The diet had no effect on growth performance and did not affect body composition evaluated at 63 days of age. Glycolytic and oxidative energy metabolisms in the liver and glycogen storage in liver and Sartorius muscle at 63 days of age were greater in chicken fed LL diet compared with chicken fed HL diet. In Pectoralis major (PM) muscle, energy metabolisms and glycogen content were not different between diets. There were no dietary-associated differences in lipid contents of the liver, muscles and abdominal fat. However, the percentages of saturated (SFA) and monounsaturated fatty acids (MUFA) in tissue lipids were generally higher, whereas percentages of polyunsaturated fatty acids (PUFA) were lower for diet LL than for diet HL. The fat line had a greater feed intake and average daily gain, but gain to feed ratio was lower in that line compared with the lean line. Fat chickens were heavier than lean chickens at 63 days of age. Their carcass fatness was higher and their muscle yield was lower than those of lean chickens. The oxidative enzyme activities in the liver were lower in the fat line than in the lean line, but line did not affect energy metabolism in muscles. The hepatic glycogen content was not different between lines, whereas glycogen content and glycolytic potential were higher in the PM muscle of fat chickens compared with lean chickens. Lipid contents in the liver, muscles and abdominal fat did not differ between lines, but fat chickens stored less MUFA and more PUFA in abdominal fat and muscles than lean chickens. Except for the fatty acid composition of liver and abdominal fat, no interaction between line and diet was observed. In conclusion, the amount of lipids stored in muscles and fatty tissues by lean or fat chickens did not depend on the dietary energy source.

Three Dissimilar High Fat Diets Differentially Regulate Lipid and Glucose Metabolism in Obesity‐Resistant Slc:Wistar/ST Rats

Epidemiologic and ecologic studies suggest that dietary fat plays an important role in the development of obesity. Certain Wistar rat strains do not become obese when fed high-fat diets unlike others. In a preliminary study, we confirmed that Slc:Wistar/ST rats did not become obese when fed high-fat diets. The mechanisms governing the response of hepatic lipid-metabolizing enzymes to large quantities of dietary lipids consumed by obesity-resistant animals are unknown. The aim of the present study is to examine how obesity-resistant animals metabolize various types of high-fat diets and why they do not become obese. For this purpose, male Slc:Wistar/ST rats were fed a control low-fat diet (LS) or a high-fat diet containing fish oil (HF), soybean oil (HS), or lard (HL) for 4 weeks. We observed their phenotypes and determined lipid profiles in plasma and liver as well as mRNA expression levels in liver of genes related to lipid and glucose metabolism using DNA microarray and quantitative reverse transcriptase polymerase chain analyses. The body weights of all dietary groups were similar due to isocaloric intakes, whereas the weight of white adipose tissues in the LS group was significantly lower. The HF diet lowered plasma lipid levels by accelerated lipolysis in the peroxisomes and suppressed levels of very-low-density lipoprotein (VLDL) secretion. The HS diet promoted hepatic lipid accumulation by suppressed lipolysis in the peroxisomes and normal levels of VLDL secretion. The lipid profiles of rats fed the LS or HL diet were similar. The HL diet accelerated lipid and glucose metabolism.

Performance of formulated diets with different level of lipids and glutamate supplementation inOctopus vulgaris

Growth, feed efficiency and proximate and lipid class composition of subadults Octopus vulgaris (788 ± 133 g; 18.5°C) fed formulated diets of low lipid (LL: 8 g kg−1) and high lipid levels (HL: 84 g kg−1) and each one of these with three different levels of glutamate supplementation (0, 5 and 20 g kg−1) were compared. All the animals accepted the diets with a survival of 100%. The addition of glutamate did not stimulate feeding rates in any of the assays (2.48–2.64 and 1.86–2.01%Body weight day−1 for LL and HL, respectively; P > 0.05). The best growth, feed efficiency and protein productive value were observed in the groups fed 5 or 20 g kg−1 glutamate supplementation at both lipid levels, with significant differences for LL diet (P < 0.05). A better feed efficiency was achieved with the HL diet (14.6–27.5% vs. 2.5–19.2% for LL diet). There were no significant differences in the proximate composition of carcass (animal excluding the digestive gland). However, a substantial amount of lipids accumulated in the digestive gland, mainly triglycerides, was detected as a consequence of higher lipid ingestion or glutamate supplementation. It was notable the lower percentages of phosphatidylethanolamine and phosphatidylcholine in the digestive gland of animals with best growth.

Effects of dietary lysine levels on apparent nutrient digestibility and cationic amino acid transporter mRNA abundance in the small intestine of finishing pigs, Sus scrofa

One hundred and twenty pigs were used to evaluate the effects of different dietary lysine levels on the growth performance, apparent nutrient digestibility, and abundance of cationic amino acid transporter messenger RNA (mRNA) in the small intestine of finishing pigs. Pigs received a low lysine diet (LL, 0.60% lysine), moderate lysine diet (ML, 0.80% lysine) or a high lysine diet (HL, 1.00% lysine) for 28 days. A digestion test was carried out during the third week. Although the apparent nutrient digestibility in pigs fed experimental diets were different (P < 0.05) and the highest when pigs were fed ML diet, diets did not change the growth performance. In the duodenum, mRNA abundance of PepT-1, as detected by real-time RT-PCR, was reduced in the LL diet (P < 0.05). A greater abundance of b(0,+) AT and PepT-1 mRNA was associated with the ML diet (P < 0.05) in the jejunum and ileum, respectively. In the ileum, the HL diet had a lower abundance of CAT-1 mRNA compared with other diets. These results showed that the finishing pigs would gain better nutrient digestibility when the dietary lysine content was 0.80%, and dietary lysine levels influenced the expression of cationic amino acid transporter mRNA in the small intestine of finishing pigs.

Effects of a lignin-rich fibre diet on productive, reproductive and endocrine parameters in nulliparous rabbit does

In rabbits, modifications in dietary composition may be associated with reproductive benefits. However, the influence of nutrition on ovarian function and embryo development is poorly known in this species. The goal of this work was to study the short-term effects of feeding high-fibre diets with different levels of lignin during the rearing period on productive, endocrine and reproductive parameters of nulliparous rabbit does. A total of 95 New Zealand × California 11-week-old nulliparous white rabbits were randomly allocated in two experimental groups fed ad libitum fibre-rich diets with a high lignin content (HL group: NDF 49.6% of DM, LAD 15.8% of DM; n = 48) or a standard lignin content (SL group: NDF 40.9% of DM, LAD 4.9% of DM; n = 47). All animals were artificially inseminated (AI) at 16 weeks of age. Daily feed intake and live body weight (LBW) were recorded during the rearing period. Conception rate and prolificacy were also determined. In addition, in ten animals of each group, body composition, serum estradiol 17β (E 2), progesterone (P 4) and leptin levels, as well as reproductive parameters including ovary weight, follicular population, ovulation rate, in vitro oocyte maturation (IVM), blastocyst recovery rate and in vitro embryo development were studied at AI time. Animals fed the HL diet had a significantly higher feed intake until the first AI ( P < 0.003) and during the first pregnancy ( P < 0.03). At 16 weeks of age, animals fed the HL diet had a lower content of lipids ( P < 0.05) and crude energy ( P < 0.05) than those fed the SL diet, but average LBW of does, ovary weight, and ovulation rate per doe were similar between HL and SL treatments. No significant differences were found in P 4 levels. However, the HL group had elevated E 2 serum levels ( P < 0.003) compared to those fed with the SL diet, whereas antral follicular population was similar between groups. Both nuclear and cytoplasmic IVM measured as metaphase II and cortical granule migration rates were also similar between both groups. In addition, no differences in blastocyst recovery rate or in prolificacy were found. However, mean serum leptin levels ( P < 0.05), in vitro embryo development ( P < 0.03), and fertility rate ( P < 0.02) were higher in the SL group compared to the HL group. In conclusion, the HL diet enhanced feed intake of does, but reduced serum leptin levels at AI time, in vitro embryo survival and conception rate.