MC Diet Research Articles

Physiological effects of long-term feeding diets supplemented with potato fibre or cellulose to adult rats

Nutritional value of diets containing 10% potato fibre or cellulose (diets MPF and MC, respectively) and their long-term effects on parameters related to potential health benefits were studied in rats. In a first experiment nutrient digestibility and metabolisable energy of the diets were determined. In a second experiment, each diet was fed to 20 male and 20 female rats aged nine weeks old during 12 (Lot W12) or 24 (Lot W24) weeks. Feed intakes per cage and body weight of rats were registered. In all animals organ weight was determined and in animals of Lot W12 and in males of Lot W24 biochemical blood parameters were analysed. In males of Lot W24, caecal SCFA concentration and body composition were also determined. Testosterone blood concentration was determined in males of Lots W12 and W24. Protein and fat digestibilities were lower, while those of ash, crude fibre and NFE were higher in the MPF than the MC diet. The energy value of the MPF diet was greater but energy intake was similar for both diets. Body weight, body protein and fat contents in males of Lot W24 did not differ between the groups, while body ash was significantly greater in MPF than MC rats (2.64 vs. 2.17 g/100 g BW). SCFA concentration and pool were considerably greater in MPF than MC rats, the SCFA profile being similar. Potato fibre did not affect total cholesterol, whereas it decreased triglycerides and very low density lipoproteins (VLDL) in Lot W12 of both genders, and tended to decrease them in males of Lot W24. Blood glucose and testosterone concentrations and relative mass of prostate were significantly depressed by the MPF diet in males of Lot W24. It can be concluded that feeding potato fibre stimulates caecal fermentation, improves mineral absorption and does not affect total cholesterol levels. The concentration of lipids, VLDL, glucose and testosterone depended on potato fibre in an age-dependent way.

High dietary methionine plus cholesterol stimulates early atherosclerosis and late fibrous cap development which is associated with a decrease in GRP78 positive plaque cells

The role of homocysteine, or its precursor methionine, in the formation of fibrous caps and its association with endoplasmic reticulum (ER) stress is unclear. Homocysteine can stimulate collagen accumulation and upregulate the ER stress chaperone glucose regulated protein 78 (GRP78). The aim of this study was to determine if high dietary methionine would increase fibrous caps, and that removal of an atherogenic diet would decrease the amount of ER stressed cells. New Zealand white rabbits were fed for 2, 4, or 12 weeks an atherogenic diet [1% methionine + 0.5% cholesterol (2MC, 4MC or 12MC)]; for 4 or 12 weeks a 0.5% cholesterol diet (4Ch, 12Ch); and to study plaque regression, an MC diet for 2 or 4 weeks accompanied by 10 weeks of a normal diet (2MCr, 4MCr). Endothelial function, atherosclerosis and GRP78 positive cells were studied. Endothelial function was abolished in 4MC and atherosclerosis increased 17-fold (P < 0.05) compared with 4Ch. Fibrous caps composed 48% of total plaque area in 12MC vs. 10% in 12Ch (P < 0.01), and 12MC expressed less GRP78 plaque cells vs. 12Ch (P < 0.01). Four MCr had less plaque GRP78 cells than 12MC (P < 0.05) and less endothelial GRP78 cells (P < 0.01). In addition, GRP78 positive cells were the highest in 4MC, but decreased in all other groups (P < 0.01). GRP78 positive cells within the fibrous cap inversely correlated with cap size (r(2) = 0.9). These studies suggest that high dietary methionine could be beneficial for plaque stabilisation, and a normal diet also stabilises plaque and decreases the number of stressed plaque cells.

Effect of medium‐ and long‐chain fatty acid diets on PPAR and SREBP‐1 expression and glucose homeostasis in ACBP‐overexpressing transgenic rats

Acyl-CoAs are important intermediates and regulators of lipid metabolism. Binding proteins like acyl-CoA binding protein (ACBP) can influence their regulatory functions. ACBP has also been shown to exert direct effects on gene regulation in vitro. As the physiological relevance of ACBP in the regulation of lipid metabolism under high fat diets is unclear, we investigated the influence of such diets on the metabolic responses in ACBP-overexpressing rats. A transgenic rat line overexpressing the ACBP gene was used to study the effects of 4 weeks of feeding with medium- (MC) or long-chain (LC) fatty acid-containing diets. Glucose tolerance tests were performed. Expression of transcription factors was measured by quantitative RT-PCR and protein levels of AMP-activated protein kinase were determined by western blotting. Transgenic animals fed the MC diet had an improved glucose tolerance and lower serum insulin levels compared with controls. Their liver PPARgamma (by 43%) and SREBP-1 (by 35%) mRNA levels were found to be decreased, while adipose tissue PPARgamma expression was increased by 31%. Tg animals fed the LC diet did not exhibit changes in glucose or insulin levels but exhibited increased mRNA levels of liver PPARs and SREBP-1 (1.5-3.5 times) and decreased protein levels of AMPKalpha (by 48%). Our results demonstrate that ACBP overexpression affects metabolic responses to diets with distinct difference in their fatty acid chain lengths. The molecular regulatory mechanism behind these effects seems to be an ACBP-induced tissue-specific regulation of expression of PPARs and SREBP.

Hypolipidemic and Antioxidant Activity of Mountain Celery (Cryptotaenia japonica Hassk) Seed Essential Oils

Mountain celery seed essential oils (MC-E) contained 109 compounds, including mainly nine kinds of monoterpenoids, 31 kinds of of sesquiterpenoids, and 22 kinds of alcohols. A successive gel column adsorption with solvent fractionation yielded four fractionates. The pentane fractionate revealed potent hypolipidemic but poor antioxidant activities. The ether fractionate exhibited strong hypolipidemic activity in addition to excellent 1,1-diphenyl-2-picrylhydrazyl free radical- and superoxide anion-scavenging capabilities. The third acetone fractionate only showed moderate superoxide anion-scavenging activity. Finally, the fourth methanol fractionate having a rather high content of gamma-selinene, 2-methylpropanal, and Z-9-octadecenamide uniquely revealed very strong superoxide anion-scavenging capability. All MC diets except the MC-E-added diet simultaneously exhibited both significant hypolipidemic and high-density lipoprotein-cholesterol (HDL-C)-elevating capabilities. However, all diets totally failed to affect the hepatic phospholipid levels. Conclusively, the MC-E can be fractionated by such a separation technology to produce products uniquely possessing hypolipidemic and HDL-C-elevating activities.

Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum

BackgroundAltering the macronutrient composition of the diet influences hunger and satiety. Studies have compared high- and low-protein diets, but there are few data on carbohydrate content and ketosis on motivation to eat and ad libitum intake. ObjectiveWe aimed to compare the hunger, appetite, and weight-loss responses to a high-protein, low-carbohydrate [(LC) ketogenic] and those to a high-protein, medium-carbohydrate [(MC) nonketogenic] diet in obese men feeding ad libitum. DesignSeventeen obese men were studied in a residential trial; food was provided daily. Subjects were offered 2 high-protein (30% of energy) ad libitum diets, each for a 4-wk period—an LC (4% carbohydrate) ketogenic diet and an MC (35% carbohydrate) diet—randomized in a crossover design. Body weight was measured daily, and ketosis was monitored by analysis of plasma and urine samples. Hunger was assessed by using a computerized visual analogue system. ResultsAd libitum energy intakes were lower with the LC diet than with the MC diet [P = 0.02; SE of the difference (SED): 0.27] at 7.25 and 7.95 MJ/d, respectively. Over the 4-wk period, hunger was significantly lower (P = 0.014; SED: 1.76) and weight loss was significantly greater (P = 0.006; SED: 0.62) with the LC diet (6.34 kg) than with the MC diet (4.35 kg). The LC diet induced ketosis with mean 3-hydroxybutyrate concentrations of 1.52 mmol/L in plasma (P = 0.036 from baseline; SED: 0.62) and 2.99 mmol/L in urine (P < 0.001 from baseline; SED: 0.36). ConclusionIn the short term, high-protein, low-carbohydrate ketogenic diets reduce hunger and lower food intake significantly more than do high-protein, medium-carbohydrate nonketogenic diets.

Effects of diets with distinct protein-to-carbohydrate ratios on nutrient digestibility, growth performance, body composition and liver intermediary enzyme activities in gilthead sea bream ( Sparus aurata, L.) fingerlings

The effect of replacing dietary protein with gelatinized cornstarch (GCS) on apparent digestibility coefficient (ADC), body composition, growth performance and liver enzyme activities involved in control of intermediary metabolism, was studied in Sparus aurata L. Fingerlings of S. aurata were fed 93 days three diets containing 63% protein and 5% gelatinized cornstarch (LC diet), 54% protein and 18% GCS (MC diet) or 47% protein and 26% GCS (HC diet). Diet HC gave ADC values for carbon, nitrogen and dry matter that were significantly below the corresponding values of the other diets. Fish on MC diet registered higher fresh weight than fish on LC and HC, and higher specific growth rate (SGR) than fish on HC. The lipid body content ranked in the order HC > MC > LC. High correlations between carbohydrate level and liver enzyme activity were found for pyruvate kinase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and alanine aminotransferase. For cultures of S. aurata, we conclude that carbohydrates like GCS could replace dietary protein, enhance growth rate and reduce nitrogen losses to the ambient waters when used at levels below 20%.

Free amino acid leaching from a protein-walled microencapsulated diet for fish larvae

The leaching loss of free amino acids (FAA) from an experimental protein-walled microencapsulated diet (MC) for larval fish after immersion in water was measured and compared with leaching loss from a gelatin microbound diet (MB) containing the same dietary ingredients. The loss of FAA (as a percentage of total dietary FAA) was significantly higher in the MB diet compared to the MC diet. After 5 min of re-hydration, 22% of FAA were leached from the MB diet compared with 8% from the MC diet. After 60 min, 85% of FAA from the MB diet were leached into the water compared to 17% from the MC diet. The addition of free lysine to protein-walled microcapsules (MC-L) was also investigated to determine the suitability of MC for delivering specific FAA. Lysine was incorporated into the particles with an efficiency of 7.5% and accounted for approximately 60% of the total FAA in the diet. The loss of this amino acid from MC-L after 60 min of immersion was 1.4%. The loss of specific FAA from MB and MC diets was found to be negatively and positively correlated to the hydrophobic character (hydropathy index) of each FAA, respectively. These results support the use of protein-walled microcapsules as a vector for specific dietary amino acids using a macronutrient-balanced diet.

Dietary Polyunsaturated Fatty Acids Modulate Responses of Pigs to Mycoplasma hyopneumoniae Infection

Polyunsaturated fatty acids (PUFA) are immunomodulators, but few studies have examined how these dietary components influence infectious respiratory disease. Groups of nine pigs were fed casein and corn starch-based diets containing 10.5 g/100 g corn oil (CO), linseed oil (LO), menhaden oil (MO), linseed + corn oil (LC, 1:1) and menhaden + corn oil (MC, 1:1). As a methodological control, one group of pigs (n = 15) was fed a commercial ration (control diet; C). Pigs inoculated intratracheally with Mycoplasma hyopneumoniae after 4 wk of consuming the diets were killed 3 wk later. Gross lung lesions in MO-fed pigs were less (P < 0.05) than those in LC- and MC-fed pigs. Pigs fed MO had less peribronchial inflammation (P < 0.05) than all other groups. Gross lung lesions correlated negatively with basal in vitro alveolar macrophage tumor necrosis factor (TNF) production in pigs fed diets that contained negligible levels of (n-3) PUFA (C and CO). Basal macrophage TNF production did not correlate with lung lesion scores for diets containing more (n-3) PUFA than C or CO (LO, MO, LC and MC). For pigs fed the LO, MO, LC and MC diets, mean gross lung lesions increased as the mean ratio of (n-3):(n-6) PUFA in alveolar macrophage lipids decreased. Serum levels of α1 acid glycoprotein (AGP) were less (P < 0.05) in pigs fed MO, and there was a rise in mean lung lesions scores for each PUFA-fed group as mean AGP levels increased. These results indicate that dietary PUFA can affect disease pathogenesis and that the (n-3):(n-6) PUFA ratio may modulate the host response.

Dietary polyunsaturated fatty acid effects on immune cells of the porcine lung

The effects of various dietary polyunsaturated fatty acids (PUFAs) on the function of immune cells of the porcine lung was studied. Groups of six pigs were fed diets containing 10.5% corn oil [CO; enriched in linoleic acid (18:2, n-6)], linseed oil (LO; enriched in alpha-linolenic acid (18:3, n-3)], menhaden oil (MO; enriched in eicosapentaenoic (20:5; n-3) and docosahexaenoic (22:6; n-3) acids], linseed + corn oil (1:1; LC), and menhaden + corn oil (1:1; MC) for 28-30 days. Basal levels of alveolar macrophage (m phi) tumor necrosis factor-alpha (TNF-alpha) production were higher (P < .05) for LC- and MC-fed pigs than for CO- and LO-fed pigs. Lipopolysaccharide (LPS)-stimulated LC and MC m phi s produced more TNF than m phi s from pigs fed CO, LO, and MO diets. Macrophages from pigs receiving the CO and LC diets had higher (P < .05) levels of leucine aminopeptidase than m phi s from the other dietary groups. Lipopolysaccharide did not increase m phi nitrite production over basal levels except in the MO diet group. However, LPS-stimulated m phi s from the CO, MO, and LC dietary groups produced more nitrite than m phi s from MC-fed pigs. Alveolar lymphocytes from pigs receiving the MC diet produced more T cell growth factors than LO and MO m phi s. Alveolar m phi s from the different dietary groups did not differ in their capacity for non-immune-mediated phagocytosis of fluorescent latex beads. These results indicate that dietary PUFAs can modulate some functions of porcine alveolar immune cells and that this may prove significant for host response to respiratory disease agents.

Grape marc and maize cobs in heavy lamb diets

For each diet, the voluntary intake and live weight gain were measured with 3 lambs, initially 2 months old, over a period of 50 d. Digestibility was measured by intake/excretion balance in 4 4month-old lambs. The digestibility of the dry matter (DM), organic matter (OM), gross energy (GE), crude protein (CP) and NDF in diets GMGM and GM decreased (P< 0.05) with the increasing percentage of grape marc. Generally smaller and non-significant differences were observed in the second experiment, but in diets MC and MC the digestibility of GE was lower (P < 0.05) than in MCIn both trials there was a modest non-significant negative digestive interaction between the hay and the by-product. The maximum DM intake was recorded in diets containing both lucerne and the by-products: 147 g/LW for the GM diet and 139 g/LW for the MC diet. The GM diet produced a lower daily gain than the GM diet (-98 g/d), while GM had an intermediate gain. In the MC diets the best result was obtained with the MC diet (70 gld higher than MC

Effects of feeding a high level of D-glucose on liver function in juvenile white sturgeon (Acipenser transmontanus)

Juvenile white sturgeon (Acipenser transmontanus) were fed three isonitrogenous and isoenergetic diets containing either 35% D-glucose (HC), a mixture of 20% dextrin and 10% cellulose (MC), or 23% cellulose (LC), to investigate the effects of dietary carbohydrate on liver function. After 8-week feeding, body weight gain of fish fed the HC diet was consistently higher than that of fish fed the MC and LC diets, but was not significantly different from the MC-fed fish. Fish fed the HC diet had significantly (p < 0.05) higher feed efficiencies and liver glycogen concentrations than fish fed the MC and LC diets. Sturgeon were injected intravenously with 10 mg kg(-1) body weight of sulfobromophthalein (BSP) and post-injection blood taken from the caudal vein at 15, 30, 60, and 120 min. No significant differences in plasma BSP concentrations were found among the treatments at these times. Plasma hemoglobin and activities of aspartate and alanine aminotransferase were not affected by the diets. This study suggests that the HC diet does not adversely affect liver function or weight gain. Inclusion of high dietary levels of digestible and inexpensive carbohydrates in commercial sturgeon feeds seems promising, but long-term feeding trials should be conducted to confirm this assertion.