CH Diet Research Articles

Bioactivity and bioavailability of minerals in rats loaded with cholesterol and kiwi fruit

The aim of this study was to compare the content of polyphenols (TP), minerals, ascorbic acid (AA) and total antioxidant capacities (TAC) of conventional and organic kiwifruit ‘Hayward’ treated with ethylene after harvest and to determine their influence on plasma TAC, mineral content in the liver and bioavailability (RBV — relative bioavailability value) in rats fed diet containing cholesterol. Organic and conventionally grown kiwifruits ‘Hayward’ as supplementation to rat diet were investigated in vitro for their bioactive compounds (polyphenols, flavonoids, flavanols, tannins, dietary fiber, and ascorbic acid), minerals, trace elements and TAC. In the in vivo investigation, 36 male Wistar rats (111±5g) were randomly divided into six diet groups, each of 6 rats: control without cholesterol (C) and 5 groups with 1% cholesterol (ch). Four cholesterol groups were supplemented with 5% lyophilized kiwifruit: ethylene treated, organic (chOHE) or conventional (chCHE) and untreated, and organic (chOHC) or conventional (chCHC). During a period of 33days of ad libitum feeding feed intake, body weight and feed utilization ration (FER) were controlled. In the end of the experiment rats were anesthetized using Narcotan and sacrificed, and blood and liver were assessed. Testing of antioxidant activity in plasma, minerals and trace elements in the diet and in the liver was performed. Ethylene-treated organic kiwifruit (OHE) had the highest content of TP and TAC. Mg content was significantly higher and Mn was lower in organic kiwifruit ‘Hayward’. Inverse relationship in the case of Mn in conventional kiwifruit was found. Supplementation of kiwifruit in ch diet groups improved diet palatability, influenced the increase of feed intake and body gain and also improved FER (lower values). Significant increase of plasma TAC for DPPH (19%), FRAP (68%) and ABTS (62%) in rats fed diets with kiwifruits was obtained. Ethylene treated conventional and organic kiwifruit improved (vs ch group) the antioxidant status of the rat body. Bioavailability of Mn and Zn in rats, calculated on the basis of its content in the liver was significantly lower in chOHC in comparison with ch group. Supplementation of ch diet groups with kiwifruit significantly decreased Mg bioavailability. Ethylene treated kiwifruit had no effect on mineral bioavailability in rats. Organic kiwifruit ‘Hayward’ contains more bioactive compounds, and showed higher antioxidant capacity than the conventional. Ethylene treatment of kiwifruit after harvest increases its bioactivity. Growing conditions of kiwifruit affect their Mg and Mn contents. Supplementation of kiwifruit in atherogenic diet increased plasma antioxidant capacity in rats. Similar effect was estimated for organic and conventional fruits. The ethylene treated kiwifruit significantly decreased magnesium bioavailability determined on the basis of its concentration in the liver. Supplementation of Mg in hypercholesterolemia is an important factor.

A palatable hyperlipidic diet causes obesity and affects brain glucose metabolism in rats

BackgroundWe have previously shown that either the continuous intake of a palatable hyperlipidic diet (H) or the alternation of chow (C) and an H diet (CH regimen) induced obesity in rats. Here, we investigated whether the time of the start and duration of these feeding regimens are relevant and whether they affect brain glucose metabolism.MethodsMale Wistar rats received C, H, or CH diets during various periods of their life spans: days 30-60, days 30-90, or days 60-90. Experiments were performed the 60th or the 90th day of life. Rats were killed by decapitation. The glucose, insulin, leptin plasma concentration, and lipid content of the carcasses were determined. The brain was sliced and incubated with or without insulin for the analysis of glucose uptake, oxidation, and the conversion of [1-14C]-glucose to lipids.ResultsThe relative carcass lipid content increased in all of the H and CH groups, and the H30-60 and H30-90 groups had the highest levels. Groups H30-60, H30-90, CH30-60, and CH30-90 exhibited a higher serum glucose level. Serum leptin increased in all H groups and in the CH60-90 and CH30-90 groups. Serum insulin was elevated in the H30-60, H60-90, CH60-90, CH30-90 groups. Basal brain glucose consumption and hypothalamic insulin receptor density were lower only in the CH30-60 group. The rate of brain lipogenesis was increased in the H30-90 and CH30-90 groups.ConclusionThese findings indicate that both H and CH diet regimens increased body adiposity independent treatment and the age at which treatment was started, whereas these diets caused hyperglycemia and affected brain metabolism when started at an early age.

Effects of a skullcap root supplement on haematology, serum parameters and antioxidant enzymes in rabbits on a high-cholesterol diet

We studied the effects of Scutellaria baicalensis root on blood parameters and antioxidant enzyme activities in rabbits fed a high-cholesterol diet. Thirty-two New Zealand White rabbits were divided into four groups of eight animals each. They were fed a standard diet (C group), a diet with a 1% pure cholesterol supplement (CH group), a diet with a 1% pure cholesterol supplement and a 9% skullcap root supplement (CH+SR group), or a diet with a 9% skullcap root supplement (SR group). After 6 weeks, the rabbits fed the high-cholesterol diet had significantly decreased RBC and Hb levels and significantly increased MCV, MCH and Fe levels (p≤ 0.05). The skullcap root supplement had no adverse effects on the haematological parameters. The values for RBC, Hb, HCT, MCV, MCH and MCHC were similar in the skullcap root-treated and control rabbits. We also observed a remarkable elevation in the serum TC, LDL and TG levels at the end of the 6-week period. The rabbits fed the cholesterol diet showed decreased activity of the erythrocyte GSH-Px compared with the rabbits fed the basal diet. The GSH-Px activity was significantly higher in the rabbits fed the CH+SR diet than in those on the CH diet. The erythrocyte SOD activity was also significantly decreased in the rabbits on the CH diet. However, the CH+SR group rabbits showed significantly enhanced erythrocyte SOD activity. The SOD level in the CH+SR rabbits was 34.91 U/ml, which was a 23% increase (p≤ 0.05) in relation to the results for the CH group and only 15% diminished in relation to the control group. These results suggest that the dietary supplementation of skullcap root may improve rabbit antioxidant systems and protect against the risks from a high-cholesterol diet.

The Effects of Feeding on Muscle Growth Dynamics and the Proliferation of Myogenic Progenitor Cells during Pike Perch Development (Sander lucioperca)

Abstract The effects of feeding on the development and growth of pike perch muscle and on proliferation of their progenitor myogenic cells were evaluated. Larvae were fed starting on Day 5 after hatching with Artemia nauplii, two commercial diets (Aglo Norse [AN] and Biokyowa [BK]), and two formulated diets (C [nonhydrolyzed casein] and CH [25% casein hydrolysate]). The survival, body mass, and length of pike perch juveniles fed Artemia nauplii and AN and BK diets were significantly higher compared to the C and CH groups. The highest somatic growth rate was associated with an increased contribution of hyperplasia to white muscle growth. Significantly higher frequency of proliferating cell nuclear antigen‐ and Ki‐67‐positive nuclei in the white muscle of fish fed Artemia nauplii and commercial diets compared to those fed C and CH feeds indicates that feeding affected the number of fibers. The pike perch fed the CH diet exhibited significantly lower total cross‐section area and average fiber area, additionally to the pathological changes in muscle morphology. The larvae fed natural food and diets promoting a fast growth rate exhibited a higher contribution of hyperplasia to muscle growth, which in turn, promoted an increase in the body size of adult fish.

Intestinal growth and function of broiler chicks fed sorghum based diets differing in condensed tannin levels

The effect of feeding sorghum condensed tannins on intestinal growth, function and histology was investigated in an 8-week broiler growth trial. Four sorghum varieties of different proanthocyanidins (PA) content; DC75 (DC - 2.48 A550nm/g DM) Chirimaugute (CH - 1.68 A550nm/g DM), Brown Tsweta (BT - 0.2 A550nm/g DM), SV2 (SV - 0.07 A550nm/g DM) and maize (MA) were used to formulate four diets each with one sorghum variety (CH, BT and SV) and maize included as the principal energy source. DC75 was used to replace 50 (DC50) and 100% (DC100) w/w maize to form the other two treatment diets. Relative weights of the small intestine differed significantly at 21 days of age. However, the decrease in weight did not correspond to the increase in PA level in a linear manner. Villus height and crypt depth were reduced at seven (7%) and 14 days (15%) in broilers fed DC and CH diets and thereafter was similar to MA and SV fed birds. The liver total and esterified cholesterol was reduced in DC100, DC50 and CH fed birds. Grain sorghum contains other phytochemicals such as policosanols and sterols besides PA which compound the observations in the liver. The effect of age on the severity of local liver lesions was not significant. The DC100 fed chicks showed mild crypt necrosis and/or sub-acute crypt distortion. There was a significant increase in the goblet cell number/mm2 measured in the jejunum of chicks fed CH, DC50 and DC100 diets. Sucrase but not maltase activity was significantly reduced with increased PA content in the 7-, 14- and 21-days age groups. From the results it appears that the dietary PA levels are not limiting factors in the development of the gastrointestinal tract of broiler chicks. Keywords : Sorghum; condensed tannins; intestinal adaptation; villus height; goblet cell density South African Journal of Animal Science Vol. 37 (3) 2007: pp.202-214

Altered Hypothalamic Signaling and Responses to Food Deprivation in Rats Fed a Low‐Carbohydrate Diet

To model how consuming a low-carbohydrate (LC) diet influences food intake and body weight. Food intake and body weight were monitored in rats with access to chow (CH), LC-high-fat (HF), or HF diets. After 8 weeks, rats received intracerebroventricular injections of a melanocortin agonist (melanotan-II) and antagonist (SHU9119), and feeding responses were measured. At sacrifice, plasma hormones and hypothalamic expression of mRNA for proopiomelanocortin (POMC), melanocortin-4 receptor, neuropeptide Y (NPY), and agouti related protein (AgRP) were assessed. A second set of rats had access to diet (chow or LC-HF) for 4 weeks followed by 24 h food deprivation on two occasions, after which food intake and hypothalamic POMC, NPY, and AgRP mRNA expression were measured. HF rats consumed more food and gained more weight than rats on CH or LC-HF diets. Despite similar intakes and weight gains, LC-HF rats had increased adiposity relative to CH rats. LC-HF rats were more sensitive to melanotan-II and less sensitive to SHU9119. LC-HF rats had increased plasma leptin and ghrelin levels and decreased insulin levels, and patterns of NPY and POMC mRNA expression were consistent with those of food-deprived rats. LC-HF rats did not show rebound hyperphagia after food deprivation, and levels NPY, POMC, and AgRP mRNA expression were not affected by deprivation. Our results demonstrate that an LC diet influences multiple systems involved in the controls of food intake and body weight. These data also suggest that maintenance on an LC-HF diet affects food intake by reducing compensatory responses to food deprivation.

A comparison of the effects of cheese and butter on serum lipids, haemostatic variables and homocysteine

Milk fat contains considerable amounts of saturated fatty acids, known to increase serum cholesterol. Little is known, however, about the relative effect of different milk products on risk factors for CHD. The aim of the present study was to compare the effects of Jarlsberg cheese (a Norwegian variety of Swiss cheese) with butter on serum lipoproteins, haemostatic variables and homocysteine. A controlled dietary study was performed with twenty-two test individuals (nine men and thirteen women) aged 23-54 years. The subjects consumed three isoenergetic test diets, with equal amounts of fat and protein, and containing either cheese (CH diet), butter + calcium caseinate (BC diet) or butter + egg-white protein (BE diet). The study was a randomised cross-over study and the subjects consumed each diet for 3 weeks, with 1 week when they consumed their habitual diet in between. Fasting blood samples were drawn at baseline and at the end of each period. Serum was analysed for lipids and plasma for haemostatic variables and homocysteine. Total cholesterol was significantly lower after the CH diet than after the BC diet (-0.27 mmol/l; P=0.03), while the difference in LDL-cholesterol was found to be below significance level (-0.22 mmol/l; P=0.06). There were no significant differences in HDL-cholesterol, triacylglycerols, apo A-I, apo B or lipoprotein (a), haemostatic variables and homocysteine between the diets. The results indicate that, at equal fat content, cheese may be less cholesterol increasing than butter.

Dietary cholesterol stimulates CYP7A1 in rats because farnesoid X receptor is not activated.

Cholesterol feeding upregulates CYP7A1 in rats but downregulates CYP7A1 in rabbits. To clarify the mechanism responsible for the upregulation of CYP7A1 in cholesterol-fed rats, the effects of dietary cholesterol (Ch) and cholic acid (CA) on the activation of the nuclear receptors, liver X-receptor (LXR-alpha) and farsenoid X-receptor (FXR), which positively and negatively regulate CYP7A1, were investigated in rats. Studies were carried out in four groups (n = 12/group) of male Sprague-Dawley rats fed regular chow (control), 2% Ch, 2% Ch + 1% CA, and 1% CA alone for 1 wk. Changes in mRNA expression of short heterodimer partner (SHP) and bile salt export pump (BSEP), target genes for FXR, were determined to indicate FXR activation, whereas the expression of ABCA1 and lipoprotein lipase (LPL), target genes for LXR-alpha, reflected activation. CYP7A1 mRNA and activity increased twofold and 70%, respectively, in rats fed Ch alone when the bile acid pool size was stable but decreased 43 and 49%, respectively, after CA was added to the Ch diet, which expanded the bile acid pool 3.4-fold. SHP and BSEP mRNA levels did not change after feeding Ch but increased 88 and 37% in rats fed Ch + CA. This indicated that FXR was activated by the expanded bile acid pool. When Ch or Ch + CA were fed, hepatic concentrations of oxysterols, ligands for LXR-alpha increased to activate LXR-alpha, as evidenced by increased mRNA levels of ABCA1 and LPL. Feeding CA alone enlarged the bile acid pool threefold and increased the expression of both SHP and BSEP. These results suggest that LXR-alpha was activated in rats fed both Ch or Ch + CA, whereas CYP7A1 mRNA and activity were induced only in Ch-fed rats where the bile acid pool was not enlarged such that FXR was not activated. In rats fed Ch + CA, the bile acid pool expanded, which activated FXR to offset the stimulatory effects of LXR-alpha on CYP7A1.

Impact of dietary FA and energy restriction on plasma leptin and ob gene expression in mice.

The aim of the present study was to elucidate whether the qualitative composition of dietary fat influences plasma leptin and adipose tissue ob gene expression differentially. Two high-fat diets and a diet rich in carbohydrate were each administered both ad libitum and with a 25% energy restriction. The high-fat diets contained 58 energy percent as either monounsaturated FA (MUFA) or saturated FA (SAFA), whereas the carbohydrate-rich diet (CH) contained 7 energy percent as fat. We aimed at obtaining the same final weight for the animals in the ad libitum group as in the energy-restricted groups. This goal was reached at the same time (days 22-24) for all groups except for the ad libitum animals fed on saturated fat (day 36). The plasma leptin concentrations on ad libitum CH and MUFA diets did not differ significantly (24.3 +/- 2.1 and 34.7 +/- 6.7 ng/mL, respectively) whereas the saturated fat diet caused a lower concentration (13.9 +/- 1.9 ng/mL; P < 0.05). Interestingly, no differences in plasma leptin levels between groups were seen in the energy-restricted groups (mean 8.0 +/- 1.0 ng/mL). The type of diet did not alter the ob gene expression in intraabdominal white adipose tissue; however, a lower expression level was found in the energy-restricted groups. The percentage of body fat in the three ad libitum fed groups did not differ (23 +/- 1%). Thus, short-term administration of a diet rich in SAFA suppresses circulating leptin levels without altering the adipose tissue ob gene expression. This indicates that saturated fat may alter protein handling by adipose tissue or the whole body clearance of leptin.

Effects of infantile overnutrition and adulthood high fat feeding on adult body weight regulation in rats

The effects of infantile overnutrition and adulthood high fat feeding on adult body weight and composition regulation as well as carbohydrate metabolism were examined in rats. Prenatal overnutrition by unilateral uterine horn ligation produced heavier but not fatter newborn rats than normally nourished newborn rats. Postnatal small litter size did not produce any noticeable increase in body weight or % fat at weaning. In adulthood, rats fed a high fat (HF) diet gained more weight and had more body fat than their chow (CH) fed counterparts. Nevertheless, obesity produced by HF feeding did not impair glucose tolerance. After withdrawal of HF diet when only CH diet was available, formerly HF fed rats had similar body weights as CH fed rats, but they still had more body fat mass than CH fed rats. Therefore, infantile overnutrition did not predispose adult obesity while adult feeding practice did. Even though the obese individuals normalized their body weights, the change in body composition may be permanent.

Diet-induced alterations in theobromine disposition and toxicity in the rat

To assess the potential influence of diet on theobromine (TBR) disposition and the development of TBR-induced thymic and testicular toxicity, male Sprague-Dawley rats were given the following diets ad libitum for 28 days: (1) semipurified (S); (2) commercial chow (Ch); (3) semipurified + 0.6% TBR (S + TBR); or (4) commercial chow + 0.6% TBR (Ch + TBR). Toxicity endpoints determined in each TBR group indicated that Ch + TBR-treated animals did not exhibit the marked reduction in body weight or testicular atrophy induced by the S + TBR diet, although thymic weight was lower regardless of diet. Metabolic studies performed after the 28-day feeding period using 5 mg/kg TBR + 10 μCi [8- 14C]TBR revealed an overall inductive effect of Ch on TBR metabolism as shown by increased urinary excretion (0–24 hr) of the major TBR metabolite, 6-amino-5[ N-methylformylamino]-1-methyluracil (6-AMMU), as well as 7-methylxanthine + 3-methylxanthine (7-MX + 3-MX) and 3,7-dimethyluric acid (3,7-DMU). Consumption of 0.6% TBR for 28 days in either S or Ch diets also induced its own metabolism, as shown by decreased urinary excretion of unchanged TBR and increased conversion primarily to 3,7-DMU. Fecal 14C elimination (0–24 hr) was similar between animals fed S and Ch diets, indicating no effect of control diet on TBR bioavailability. Since serum TBR concentrations and overall toxicity were lower in Ch + TBR-treated animals than in S + TBR treated animals, yet TBR bioavailability was similar, this effect was attributed to the inducing potential of the Ch diet on TBR metabolism and clearance. Investigators are cautioned to consider the potential effect of diet on metabolism when performing and evaluating toxicological studies.

Influence of dietary alfalfa:orchardgrass hay and lasalocid on in vitro estimates of dry matter digestibility and volatile fatty acid concentrations of cecal contents and rate of digesta passage in sows.

Four mature crossbred sows were fistulated in the cecum, with two sows fed a corn-alfalfa:orchardgrass hay (46%) diet (CH) and two fed a corn-soybean meal diet (CS). Four experiments were conducted to evaluate buffers, incubation times, buffer pH and substrate and inocula sources in an in vitro, anaerobic, mixed-culture system. In vitro dry matter digestibility (IVDMD) and substrate solubility in buffer (SS) were determined. In Exp. 1, substrates were CH and CS diets with cecal inocula obtained from CH- and CS-fed sows. The bicarbonate (B) buffer resulted in lower (P less than .01) and less variable SS for all treatments. In vitro dry matter digestibility was higher (P less than .01) for the CS diet at both 24 and 48 h incubation. Use of the B buffer also resulted in higher (P less than .001) IVDMD values. In Exp. 2, substrates were either as in Exp. 1 or were freeze-dried cecal contents (CC) from CH- or CS-fed sows. In vitro dry matter digestibility of CC was lower (P less than .006) than IVDMD of diet, while IVDMD was higher (P less than .02) with cecal inocula than fecal inocula. In Exp. 3, substrate-inocula treatments were CH-CH, CH-CS, CS-CH and CS-CS. Substrate solubility was lower (P less than .05) at pH 5.8 than at pH 6.8. In vitro dry matter digestibility was higher when substrate and inocula were from the same source and at pH 5.8. In Exp. 4, CC and inocula were from sows fed CH and CS diets with or without lasalocid. In vitro dry matter digestibility was higher with CC from lasalocid-fed sows and inocula from sows fed no lasalocid. The CH diet resulted in higher acetate (Ac) and lower propionate (Pr) molar proportions than did the CS diet, while lasalocid increased molar proportion Pr and decreased molar proportion Ac in cecal contents from sows fed either diet. Corn-alfalfa:orchardgrass hay-fed sows had a faster rate of digesta passage and shorter cecal retention time than did CS-fed sows.