The Effects of Combined Treatment with Niacin and Chromium on the Renal Tissues of Hyperlipidemic Rats

In this study, 12 months old female Swiss albino rats were used. They were randomly divided into four groups. The animals of group I were fed with pellet chow. Group II were fed with pellet chow and treated with 250 μg/kg CrCl₃.6H₂o and 100 mg/kg niacinfor 45 days. Group III were fed a lipogenic diet consisting of 2% cholesterol, 0.5% cholicacidand 2%sun flower oil added to the pellet chow, andgiven 3%alcoholic water for 60 days. Group IV were fed with the same lipogeni cdiet for 60 day sand treated by gavage technique to rats at a dose of 250 mu/kg CrCl_3.6H₂O and 100 mg/kg niacin for 45 days, 15 days after experimental animals were rendered hyperlipidemic. At the 60th day, renal tissue and blood samples were taken from the animals. The sections were examined under light and electron microscopy. The degenerative changes were much more in the hyperlipidemic rats than the control group. The changes in renal tissue were also observed in hyperlipidemic animals given niacin and chromium. In the hyperlipidemic rats, renal glutathione levels decreased and renal lipid peroxidation levels, and serum urea and creatinine levels were increased. But, renal glutathione levels increased and lipid peroxidation levels and serum urea and creatinine levels decreased in hyperlipidemic rats given niacin and chromium. The purpose of this study was to investigate whether a protective effect of a combination of niacin and chromium is present on the renal tissue of hyperlipidemic rats or not. In conclusion, we can say that niacin and chromium do not have a protective effect on the morphology of the renal tissue of hyperlipidemic rats, except a protective effect on their biochemical parameters.     

Influences of Nano-TiO2 on the chloroplast aging of spinach under light

The aim of this study was to investigate the biochemical effects of niacin and chromium(III)-chloride on serum lipid peroxidation, uric and sialic acids, and the extent of lipid peroxidation and glutathione levels in skin and lung tissues of hyperlipidemic rats. In this study, female Swiss albino rats, 12 mo old, were used. They were randomly divided into four groups. Group I animals were fed with a standard pellet diet and water ad libitium. Group II rats were fed with a standard pellet diet and were treated with a dose of 250 μg/kg body weight CrCI₃·6H₂O and 100 mg/kg body weight niacin, for 45 d, by the gavage technique. Group III rats were fed a lipogenic diet in which 2% cholesterol, 0.5% cholic acid, and 20% sunflower oil were added to the pellet chow. In addition, the animals in this group drank water containing 3% ethanol. This regime was maintained for 60 d. The rats in group IV were maintained in the same food and drink regime as the animals in group III. After 2 wk, the animals showed symptoms of hyperlipemia and they were treated with 250 μg/kg body weight CrCI₃·6H₂O and 100 mg/kg body weight niacin, by gavage, for 45 d. On d 60, the blood and the skin and lungs samples were taken from animals. In the hyperlipemic groups, a reduction of the lung glutathione level and an increase in serum, lung, and skin lipid peroxidation levels and in serum sialic and uric acid were observed. In rats treated with a combination of niacin and Cr(III), the skin and serum lipid peroxidation and the sialic and uric acid levels decreased while showing an increase of lung glutathione activity. These results suggest that niacin and Cr(III), when administered in combination, have a protective effect against skin and lung tissues damage as a result of hyperlipidemia.     

Combined effects of niacin and chromium treatment on vascular endothelial dysfunction in hyperlipidemic rats

Combined treatment with niacin and chromium has been found to have a protective effect against oxidative damage to different tissues of hyperlipidemic rats. But its effects on vascular endothelial dysfunction are less clear. This study was performed to investigate the effect of combined treatment with niacin and chromium on vascular endothelial dysfunction, with the aim of gaining insight to the mechanisms by detecting the expression levels of ox-LDL and LOX-1. Twenty-four male, 4-week-old Wistar rats were randomly divided into three groups: control group (CG; n = 8), high-fat group (HF; n = 8), and drug control group (DG; n = 8).In CG group, rats were fed with pellet chow. In HF group, rats were fed with high-fat diet for 12 weeks. In DG group, rats were fed with the same high-fat diet and treated with CrCl₃ · 6H₂O (250 μg/kg days) and niacin (100 mg/kg days) by gavage technique for 12 weeks. At the end of the 12th week, samples from aorta and blood were collected. In HF group, the serum levels of total cholesterol (TC), low-density lipoprotein (LDL), oxidized low-density lipoprotein (ox-LDL) and endothelin (ET) were higher, whereas the levels of high-density lipoprotein (HDL), serum NO were lower than those in CG group. The levels of serum TC, LDL, ox-LDL and ET decreased and HDL, NO levels increased in DG group when compared with HF group. The levels of LOX-1, ICAM-1 were also observed in abdominal artery. In HF group, the protein and mRNA expression of LOX-1, ICAM-1 were elevated comparing with CG group. In DG group, the protein and mRNA expression of LOX-1, ICAM-1 were decreased obviously, but still differed significantly from those in CG group. ox-LDL was related positively to TC, LDL, ET, ICAM-1 and LOX-1, but related negatively to NO and HDL. These findings indicated that combined treatment with niacin and chromium has potential therapeutic protection of endothelial function by down-regulating ox-LDL/LOX-1 signaling pathway.     

Lack of Effect of Dietary Chromium Supplementation on Growth Performance and Serum Insulin, Glucose, and Lipoprotein Levels in Broilers Reared Under Heat Stress Condition

This study evaluated the effects of supplemental dietary chromium (Cr) on the performance, carcass traits, and some serum parameters of broilers under a heat stress (23.9 to 37 °C cycling) condition. A total of 150 1-day-old broiler chicks (Cobb 500) according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Treatments were supplemented with 0 (control), 600, and 1,200 μg kg^?1 Cr in the form of Cr chloride (CrCl₃) and Cr L-methionine from 1 to 49 days of age. Blood samples were collected from two birds in each replicate to determine serum parameters at 35 and 49 days of age. The body mass, feed intake, and conversion ratio were not influenced by dietary Cr (P?>?0.05). Dietary supplementation of Cr from either CrCl₃ or Cr L-methionine caused increased serum concentrations of Cr (P?<?0.05), but had no effect on serum insulin and glucose concentrations at both sampling times (P?>?0.05). Serum triglycerides, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were also not significantly affected (P?>?0.05) by dietary treatments, whereas total cholesterol concentration decreased in chicks fed Cr L-methionine compared to the control (P?<?0.05).     

Chromium and yogurt effects on hepatic lipid and plasma glucose and insulin of obese mice

Dietary chromium (Cr) supplements in casein or yogurt-based diets were fed to genetically obese C57BL/6J-OB (ob/ob) mice to investigate the effects of Cr and yogurt on total hepatic lipid, plasma glucose, insulin, and cholesterol levels. Diet groups were casein control (C), yogurt control (Y), yogurt plus CrCl₃ (Y + Cr) (1.83 ppm Cr), and casein plus CrCl₃ (C + Cr) (1.85 ppm Cr). Food and water were availablead libitum. No significant differences were observed in final body weight. In obese mice, total hepatic lipid was significantly greater in the C than in the C + Cr group and in the Y than in the Y + Cr group. Plasma immunoreactive insulin levels tended to be lower in animals fed C + Cr and Y + Cr diets. Plasma insulin was significantly correlated with hepatic lipid and with plasma cholesterol. By analysis of variance, bone Cr was elevated by Cr supplementation. In the obese mouse, a model for insulin resistance, Cr supplementation apparently affects both hepatic lipid concentration and bone chromium.     

Effects of dietary chromium chloride supplementation on performance,some serum parameters,and immune response in broilers

This study was conducted to investigate the effect of increasing dietary levels of inorganic chromium (CrCl₃·6H₂O) on the performance, blood chemistry, and immune response of broilers. Eighty newly hatched Ross PM3 broiler chicks were evenly distributed to five groups of 16 chicks each. Two groups (control and only sheep red blood cell inoculated) were fed the basal diet containing 2.2 and 4.5 mg Cr/kg and the remaining groups were fed 20, 40, or 80 mg/kg Cr-supplemented diets for 44 d. Chicks in all groups, except in the control, at 3 and 5 wk of age, were injected intraperitonally with sheep red blood cell for determining the primary and secondary antibody responses, respectively. When the chicks were 4 wk of age, a delayed-type hypersensitivity test was performed. White blood cells were differentiated. Blood samples were collected for the determination of serum proteins, glucose, cholesterol, cortisol, minerals, and alkaline phosphatase activity and for antibody response. Chromium had no effect on weight gain, but 20 mg/kg supplemental Cr resulted in 18.57% reduction in feed consumption and improved feed efficiency by 16.77%. Chromium did not affect serum cholesterol and P levels but reduced serum glucose and increased serum protein, Cr, Ca, and Mg levels, and ALP activity. A slight reduction was observed with Cr supplementation in cortisol levels. Slight but not significant increases were observed with Cr in serum Zn and Cu. Chromium increased the ratio of bursa of Fabricius and liver to body weight. Heterophil and monocyte counts and heterophil/lymphocyte ratio were reduced and lymphocyte counts, total antibody, IgG, and IgM titers were increased by supplemental Cr. All levels of Cr increased the cell-mediated response to phytohemagglutinin. No alterations in tissues were observed by histopathological examinations.     

Effects of dietary chromium supplementation on performance, carcass traits, serum metabolites, and tissue chromium levels of Japanese quails

This study was conducted to investigate the effects of various levels of dietary chromium supplementation on performance, carcass traits, blood chemistry, and tissue distribution of chromium (Cr³⁺) in quails. Two hundred forty 1-d-old Japanese quails were divided into five groups with four replicates and were fed a basal diet or the basal diet supplemented with 20, 40, 80, or 100 mg/kg Cr (CrCl₃·6H₂O) until 38 d of age. Chromium supplementation decreased carcass fat percentage, serum low-density lipoprotein (LDL), and glucose and increased serum magnesium (Mg) and Cr content of kidney, liver, and muscle. In conclusion, 20, 40, 80, or 100 mg/kg Cr supplementation to quail diet had no effect on performance, chemical composition of carcass except fat percentage, serum protein, calcium (Ca), and inorganic phosphorus (Pi) levels, but reduced serum glucose, LDL and fat percentage of carcass. Chromium is accumulated mainly in the kidneys and liver.     

Absorption of the biomimetic chromium cation triaqua-μ3-oxo-μ-hexapropionatotrichromium(III) in rats

The cation [Cr₃O(O₂CCH₂CH₃)₆(H₂O)₃]⁺ has been shown in vitro to mimic to the oligopeptide chromodulin’s ability to stimulate the tyrosine kinase activity of insulin receptor and shown in healthy and type 2 diabetic model rats to increase insulin sensitivity and decrease plasma total and low-density lipoprotein cholesterol and triglycerides concentrations. However, the degree to which the complex is absorbed after gavage administration to rats had not been previously determined. The biomimetic cation at nutritional supplement levels is absorbed with greater than 60% efficiency, and at pharmacological levels, it is absorbed with greater than 40% efficiency, an order of magnitude greater absorption than that of CrCl₃, Cr nicotinate, or Cr picolinate, currently marketed nutritional supplements. The difference in degree of absorption is readily explained by the stability and solubility of the cation.     

Lipopolysaccharide and tumor necrosis factor cause a fall in plasma concentration of lecithin: cholesterol acyltransferase in cynomolgus monkeys

The effects of intravenous injection of lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNF) were investigated in cynomolgus monkeys (Macaca fascicularis). Injection of 20 micrograms/kg of LPS from E. coli (serotype 055:B5) into cynomolgus monkeys fed a monkey chow diet caused a twofold increase in plasma triglyceride and a 25% reduction in plasma cholesterol 48 h after injection. Similar results were found with injection of recombinant human TNF at a dose of 20 micrograms/kg into chow-fed animals. However, injection of the same dose of LPS or TNF into animals fed an atherogenic diet containing saturated fat and cholesterol resulted in a 2.4- to 5-fold increase in plasma triglyceride concentrations and no significant change in plasma cholesterol levels. The fall in plasma cholesterol levels observed in chow-fed animals was associated with a 57% decrease in the cholesteryl ester (CE) content in low density lipoprotein (LDL) and 35% decrease in CE in high density lipoprotein (HDL) in LPS-injected animals, and a decrease of 33% in CE concentration of LDL and 41% in CE of HDL in animals injected with TNF. In animals fed the atherogenic diet containing saturated fat and cholesterol, the injection of both LPS and TNF also resulted in a significant decrease in the CE content of LDL and HDL. However, the plasma total cholesterol levels did not change in the animals fed saturated fat and cholesterol because the decrease in CE content of LDL and HDL was offset by an increase in very low density lipoprotein (VLDL)-CE.(ABSTRACT TRUNCATED AT 250 WORDS)     

Oxidative renal injury and lipoprotein oxidation in hypercholesterolemic atherogenesis: Role of eicosapentaenoate-lipoate (EPA-LA) derivative

Hypercholesterolemia, an independent risk factor for increased oxidative renal injury, is associated with the formation of oxidized low-density lipoprotein. Production of reactive oxygen species and nitrogen species have been implicated in diet-induced hypercholesterolemia, principally as means of oxidising low-density lipoproteins. This in turn initiates the accumulation of cholesterol in macrophages, which sets key event in the initiation of atherosclerosis. The aim of the present work is to evaluate the effects of eicosapentaenoic acid (EPA), DL alpha-lipoic acid (LA) and eicosapentaenoate-lipoate derivative (EPA-LA) in controlling the atherogenic disturbances. Four groups of male Wistar rats were fed with a high cholesterol diet (rat chow supplemented with 4% cholesterol and 1% cholic acid; HCD) for 30 days. Among them, 3 groups of rats were treated with either EPA (35 mg/kg body weight/day, oral gavage), LA (20 mg/kg body weight/day, oral gavage) or EPA-LA derivative (50 mg/kg body weight/day, oral gavage) from 16th day to 30th day of the experimental period. Abnormal increase in the levels of reactive oxygen species, 3-nitrotyrosine, malondialdehyde and protein carbonyl as well as an elevation in the activities of xanthine oxidase, lactate dehydrogenase, alkaline phosphatase and acid phosphatase was observed in renal tissue of HCD fed rats. HCD fed rats also showed an increased susceptibility of the apo B-containing lipoproteins to in vitro oxidation. These changes were restored partially in the EPA and LA administered groups. However, the combined derivative EPA-LA almost ameliorated the hypercholesterolemic-oxidative changes in the HCD fed rats.     

Hypoglycemic activity and acute oral toxicity of chromium methionine complexes in mice

The hypoglycemic activity of chromium methionine (CrMet) in alloxan-induced diabetic (AID) mice was investigated and compared with those of chromium trichloride hexahydrate (CrCl₃·6H₂O) and chromium nicotinate (CrNic) through a 15-day feeding experiment. The acute oral toxicity of CrMet was also investigated in ICR (Institute for Cancer Research) mice by a single oral gavage. The anti-diabetic activity of CrMet was explored in detail from the aspects of body weight (BW), blood glucose, triglyceride, total cholesterol, liver glycogen levels, aspartate transaminase (AST) and alanine transaminase (ALT) levels. The obtained results showed that CrMet had beneficial effects on glucose and lipid metabolism, and might possess hepatoprotective efficacy for diabetes. Daily treatment with 500 and 1000 μg Cr/kg BW of CrMet in AID mice for 15 days indicated that this low-molecular-weight organic chromium complex had better bioavailability and more beneficial effects on diabetics than CrCl₃·6H₂O. CrMet also had advantage over CrNic in the control of AST and ALT activities. Acute toxicity studies revealed that CrMet had low toxicity potential and relatively high safety margins in mice with the LD₅₀ value higher than 10.0 g/kg BW. These findings suggest that CrMet might be of potential value in the therapy and protection of diabetes.     

L-histidine-induced suppression of lipogenic enzymes.

Diets supplemented 5% with L-histidine produce hypercholesterolemia and increase cholesterol biosynthesis in rat liver. We now report an $\text{inhibitory}$ effect of L-histidine on lipogenic enzymes in the liver. In this study, L-histidine was added to chow and fat-free diets and fed to rats for 18 days. After two days of fasting, the rats were refed the same diet for three days prior to sacrifice. L-histidine decreased fatty acid synthetase activity by 51% when it was added to the chow diet and by 26% when it was added to the fat-free diet. Isocitrate dehydrogenase activity was not altered significantly in rats fed diets supplemented with L-histidine.     

Osbpl8 Deficiency in Mouse Causes an Elevation of High-Density Lipoproteins and Gender-Specific Alterations of Lipid Metabolism

OSBP-related protein 8 (ORP8) encoded by Osbpl8 is an endoplasmic reticulum sterol sensor implicated in cellular lipid metabolism. We generated an Osbpl8^−/− (KO) C57Bl/6 mouse strain. Wild-type and Osbpl8KO animals at the age of 13-weeks were fed for 5 weeks either chow or high-fat diet, and their plasma lipids/lipoproteins and hepatic lipids were analyzed. The chow-fed Osbpl8KO male mice showed a marked elevation of high-density lipoprotein (HDL) cholesterol (+79%) and phospholipids (+35%), while only minor increase of apolipoprotein A-I (apoA-I) was detected. In chow-fed female KO mice a less prominent increase of HDL cholesterol (+27%) was observed, while on western diet the HDL increment was prominent in both genders. The HDL increase was accompanied by an elevated level of HDL-associated apolipoprotein E in male, but not female KO animals. No differences between genotypes were observed in lecithin:cholesterol acyltransferase (LCAT) or hepatic lipase (HL) activity, or in the fractional catabolic rate of fluorescently labeled mouse HDL injected in chow-diet fed animals. The Osbpl8KO mice of both genders displayed reduced phospholipid transfer protein (PLTP) activity, but only on chow diet. These findings are consistent with a model in which Osbpl8 deficiency results in altered biosynthesis of HDL. Consistent with this hypothesis, ORP8 depleted mouse hepatocytes secreted an increased amount of nascent HDL into the culture medium. In addition to the HDL phenotype, distinct gender-specific alterations in lipid metabolism were detected: Female KO animals on chow diet showed reduced lipoprotein lipase (LPL) activity and increased plasma triglycerides, while the male KO mice displayed elevated plasma cholesterol biosynthetic markers cholestenol, desmosterol, and lathosterol. Moreover, modest gender-specific alterations in the hepatic expression of lipid homeostatic genes were observed. In conclusion, we report the first viable OsbplKO mouse model, demonstrating a HDL elevating effect of Osbpl8 knock-out and additional gender- and/or diet-dependent impacts on lipid metabolism.     

Serum lipoproteins of normal and cholesterol-fed rats

The density distribution of lipoproteins in rats fed chow or chow containing 1% cholesterol and 10% olive oil was studied. Lipoprotein fractions were prepared in the ultra-centrifuge between narrow density bands within the density range of 1.006-1.21 and were analyzed by chemical, electrophoretic, and immunological methods. In serum from normal rats there were three major lipoprotein fractions, with densities less than 1.006, 1.030-1.063, and 1.063-1.21. Almost no lipoprotein was found between d 1.006 and 1.030. Most of the low density lipoprotein appeared between a density of 1.04 and 1.05. In the density range 1.05-1.07, small amounts of both low density and high density lipoprotein were found. Feeding a diet high in cholesterol resulted in a marked increase in the concentration of lipoproteins of density less than 1.006, and a new lipoprotein fraction appeared between d 1.006 and 1.030; this fraction contained immunologically demonstrable low density and high density lipoproteins. In addition, there was a decrease in the high density lipoprotein fraction between d 1.070 and 1.21.     

Serum lipids and cholesterol distribution in lipoproteins of exercise-trained female rats fed sucrose

This study was undertaken to evaluate the combined effects of sucrose feeding and exercise training on serum insulin, triglycerides, as well as cholesterol and its distribution into lipoproteins of female Wistar rats. The animals were fed ad libitum either laboratory chow alone, or chow and a 32% aqueous sucrose solution. Half of each dietary group was submitted to an exercise-training program. Both sucrose feeding and exercise training elicited greater energy intake. Sucrose feeding produced a marked elevation in triglyceridemia that was prevented by exercise training. Insulin levels paralleled those of triglycerides. The sucrose-fed animals had higher total cholesterol levels than the animals given chow. Although exercise training did not affect total cholesterol in the chow-fed animals, it partly prevented the sucrose-induced elevation in total cholesterol. Cholesterol in the lipoproteins of lower densities was increased significantly with sucrose feeding, and exercise training totally prevented this augmentation. The amount of cholesterol carried by high-density lipoprotein (HDL) was not affected by exercise training in the chow-fed animals. In contrast, sucrose feeding increased HDL-cholesterol in sedentary animals, whereas exercise training partly prevented this increase. The HDL/total cholesterol ratio was similar in all groups. Changes in insulin concentration underline the importance of this hormone in the regulation of blood lipid levels.     

Oral administration of the biomimetic [Cr3O(O2CCH2CH3)6(H2O)3]+ increases insulin sensitivity and improves blood plasma variables in healthy and type 2 diabetic rats

The in vivo effects of gavage administration of the synthetic, functional biomimetic cation [Cr₃O(O₂CCH₂CH₃)₆(H₂O)₃]⁺ to healthy and type 2 diabetic model rats are described. After 24 weeks of treatment (0–1,000 g Cr/kg body mass) of healthy Sprague Dawley rats, the cation results in a lowering (P<0.05) of fasting blood plasma low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides, and insulin levels and of 2-h plasma insulin and glucose concentrations after a glucose challenge. Zucker obese rats (a model of the early stages of type 2 diabetes) and Zucker diabetic fatty rats (a model for type 2 diabetes) after supplementation (1,000 g Cr/kg) have lower fasting plasma total, high-density lipoprotein, and LDL cholesterol, triglycerides, glycated hemoglobin, and insulin levels and lower 2-h plasma insulin levels in glucose tolerance tests. The lowering of plasma insulin concentrations with little effect on glucose concentrations suggests that the supplement increases insulin sensitivity. The cation after 12 and 22 or 24 weeks of administration lowers (P<0.05) fasting plasma glycated hemoglobin levels in the Zucker diabetic and Zucker obese rats, respectively, and thus can improve the glucose status of the diabetic models. The effects cannot be attributed to the propionate ligand.Supplementary material is available for this article at .An erratum to this article can be found at     

Metabolism of apoprotein B in selectively bred baboons with low and high levels of low density lipoproteins

Very low density lipoprotein (VLDL) and low density lipoprotein (LDL) apoprotein (apo)-B turnover rates were measured simultaneously by injecting 131I-labeled VLDL and 125I-labeled LDL into fasting baboons (Papio sp.) selectively bred for high serum cholesterol levels and having either low or high LDL levels. The radioactivities in VLDL, intermediate density lipoprotein (IDL), LDL apoB, and urine were measured at intervals between 5 min and 6 days. Kinetic parameters for apoB were calculated in each baboon fed a chow diet or a high cholesterol, high fat diet (HCHF). VLDL apoB residence times were similar in the two groups of animals fed chow; they were increased by HCHF feeding in high LDL animals, but not in low LDL animals. Production rates of VLDL apoB were decreased by the HCHF diet in both high and low LDL animals. Most of the radioactivity from VLDL apoB was transferred to IDL. However, a greater proportion of radioactivity was removed directly from IDL apoB in low LDL animals than in high LDL animals, and only about one-third appeared in LDL. In high LDL animals, a greater proportion of this radioactivity was converted to LDL (61.4 +/- 7.2% in chow-fed animals and 49.2 +/- 10.9% in animals fed the HCHF diet; mean +/- SEM, n = 5). Production rates for LDL apoB were higher in high LDL animals than those in low LDL animals on both diets. The HCHF diet increased residence times of LDL apoB without changing production rates in both groups. VLDL apoB production was not sufficient to account for LDL apoB production in high LDL animals, a finding that suggested that a large amount of LDL apoB was derived from a source other than VLDL apoB in these animals.     

Effect of Feeding Inorganic Chromium on Growth Performance, Endocrine Variables, and Energy Metabolites in Winter-Exposed Buffalo Calves (Bubalus bubalis)

We investigated the effect of chromium (Cr) supplementation on the growth performance, energy metabolites, and hormonal variation in winter-exposed buffalo calves. Twenty-four female buffalo calves were randomly allotted to four dietary treatments (n?=?6) for a period of 120 days. Feeding regimen was the same in all the groups, except the animals in the four respective groups were additionally supplemented with 0.0, 0.5, 1.0, and 1.5 mg of Cr/kg DM in the form of CrCl₃.6H₂O. Calves were monitored daily for physiological variables and dry matter intake (DMI). Blood samples were collected at fortnightly intervals from each buffalo calves to measure concentrations of hormones (insulin, cortisol, and growth hormone), energy metabolites (glucose and non-esterified fatty acids), and plasma mineral levels. After 120 days of feeding trial, buffalo calves fed with Cr had lower (P?<?0.05) circulating plasma concentrations of glucose, insulin, and cortisol hormones, whereas plasma thyroid hormone and non-esterified fatty acids concentrations were found similar (P?>?0.05) among all the treatments. The results suggested that dietary Cr supplementation influenced plasma Cr levels without affecting the plasma concentrations of other trace minerals. However, physiological variables, nutrient intake, and growth performance of buffalo calves did not differ among all treatments (P?>?005). In summary, the current study showed that supplementation of Cr at the level of 1.0 and 1.5 mg of Cr/kg DMI was more effective in improving glucose utilization by increasing potency of insulin hormone and reducing concentration of cortisol hormone. Results also suggested that supplemental Cr also improves blood plasma Cr levels.     

The effect of dietary fat on lipogenesis in mammary gland and liver from lactating and virgin mice

1. Virgin and lactating C(3)H mice maintained on laboratory chow were transferred to a high-fat (15% corn oil) or a fat-free diet 3 days before being killed. 2. The linoleate content of liver, mammary gland and milk was decreased in lactating mice given the fat-free diet but was increased in those fed on the high-fat diet. Changes in linoleate content and mammary gland followed a similar but much less marked trend in virgin animals. 3. Hepatic fatty acid synthesis in lactating and virgin mice fed on the fat-free diet was higher than in corresponding animals fed on either the chow or the high-fat diet. The lipogenic capacity of livers from mice fed on either the chow or the high-fat diet was greater in lactating than in virgin animals. These changes in hepatic lipogenic capacity were accompanied by alterations in the specific activities of certain enzymes involved in fat synthesis. 4. Mammary gland from virgin and lactating animals showed no such adaptation to dietary fat. Results indicate that fatty acid synthesis in neither mammary-gland parenchymal cells nor mammary-gland adipose cells can be influenced by dietary fat in the same way as in the hepatocyte.