Effects Of Dietary Copper Supplementation Research Articles

Effects of dietary copper supplementation on performance, carcass characteristics, and lipolytic rate of beef steers fed ractopamine hydrochloride

Effects of dietary copper supplementation on performance, carcass characteristics, and lipolytic rate of beef steers fed ractopamine hydrochloride

Effects of dietary copper supplementation on serum and biochemical and histopathology of pubertal boars

The effects of dietary copper on some biochemistry and histopathology of organs of pubertal pigs were assessed using 32 large white male weanling pigs of 8-9 weeks of age in a 6-months feeding trial. The animals were randomly assigned to four diets containing 0, 100, 200 and 300ppm Cu/kg as the control diet (diet 1), diets 2, 3 and 4 respectively. The feeding trial was divided into 3 growth phases (weanling, pre-pubertal and pubertal) corresponding to 8, 18 and 24 weeks of life respectively. At the end of the feeding trial, all the animals were sacrificed by stunning, bled, decapacitated followed by blood collection and careful evisceration to obtain the kidney, liver, spleen and testes and samples of the small intestine. Selected organs and tissues collected from sacrificed animals were processed for histology. Results showed that dietary copper did not significantly (P>0.05) influence the blood serum biochemical composition and the histomorphology of the organs and tissues examined. The boars exposed to the diet containing the highest copper supplementation (diet 4) did not have severe splenic atrophy and/or lymphoid depletion, liver necrosis and/or lesions, intestinal mucosal erosion and testicular necrosis and/or sertoli cells degeneration as compared to those fed the control. There was no intestinal mucosal erosion with increased dietary copper in this study because the maximum level of copper that was used in this study was not above 500ppm; hence all the tissues studied did not show degeneration of any form.

EFFECT OF DIETARY COPPER SUPPLEMENTATION ON SERUM COPPER LEVEL AND PERFORMANCE OF FEMALE WEST AFRICAN DWARF (Fouta djallon) GOATS

The effects of dietary copper supplementation on serum copper level and performance were studied in a 174-day feeding experiment involving 16 female West African dwarf goats level and using depletion - repletion approach, The results obtained showed a significantly lower (P<0.05) but traces of serum copper after depletion combined with pre depletion (1.70 to 1.90 Ug/dl serum) and after 42 days of dietary repletion (1.28 to 2.50 Ug/dl serum). The best responses in terms of growth rate (0.114 kg/day) highest dry matter intake (1.43 Ugg feed DM) were induced by 240.68 Ug Cug DM of feed. The goats managed maintenance requirement for copper was 5.033 UgCuw0.75. while the dietary copper supplementation requirement was 240.68 Ug They had free access to salt licks and water. Cu/g DM of feed for optimum weight gain, growth rate and dry matter intake.

Effect of dietary copper levels on the growth performance and nutrient utilization in fattening pigs

The present study was conducted to investigate the effect of dietary copper supplementation on the growth performance, nutrient digestibility and copper metabolism in fattening pigs. A total of 24 pigs (Landrace X Large White X Duroc) with an average initial BW of 30±1.05 kg, the pigs were divided into four treatment groups, with three replicates per treatment and two pigs per replicate, in accordance with a completely randomized design based on the BW. The results indicated that dietary copper supplementation increased the growth performance, CP and EE digestibility. However, there was no significant increase in the DM and OM digestibility. In addition, copper deposition increased with the increase in dietary copper supplementation, while copper absorption, increased with the decrease in dietary copper levels. In conclusion, fattening pigs with 30-60 kg BW can utilize 45-135 mg/kg Cu and porkers at BW of 60-120 kg can also utilize 10-45 mg/kg Cu as CuSO4 for an increased copper utilization and a decreased in copper deposition.

Effects of dietary copper supplementation on performance, egg quality parameters, yolk cholesterol and fatty acid profiles in laying hens

The present study envisaged the effects of different levels of dietary copper supplementation on performance, egg quality parameters, serum and yolk cholesterol and triglyceride levels, and yolk fatty acid profile in laying hens. Total 96 Lohman laying hens (38 weeks old) were randomly divided into four groups (n=24 each). Experimental diets were prepared by adding copper (0, 200, 250 or 300 mg/kg) to basal diet and feeding was lasted 12 weeks. Dietary copper supplementation decreased egg weight and feed intake but did not affect other performance parameters compared to the control diet. Shape index, shell weight, shell thickness, yolk color, yolk index, albumen index, and haugh unit were not influenced by dietary copper supplementation, whereas shell strength increased due to the inclusion of copper in the basal diet. Copper supplementation did not affect the fatty acid profile of the egg yolk. The yolk cholesterol ratio decreased by 7.22% in the presence of 250 mg/kg copper supplementation compared to control diet. Therefore, high levels of dietary copper supplementation in the diet of laying hens can be beneficial for improving shell strength and reducing the cholesterol content of the yolk.

Effects of Dietary Copper Supplementation on Laying Performance, Egg Quality and Plasma Cholesterol Fractions in Laying Ducks

Effects of Dietary Copper Supplementation on Laying Performance, Egg Quality and Plasma Cholesterol Fractions in Laying Ducks

Effect of dietary inorganic copper on growth performance and hematological profile of Nile tilapia subjected to heat-induced stress

The effects of graded levels of dietary copper supplementation on the growth, hematological profile, ceruloplasmin activity, and resistance to high temperature stress of Nile tilapia (Oreochromis niloticus) were analyzed. A total of 240 fish (8.05±0.45g) were randomly distributed in 30 tanks (250L) and fed six diets containing graded levels of Cu2SO4·5H2O (0.0, 4.0, 6.0, 8.0, 1000 and 1500mgCu·kg−1 diet) for 120days. Growth performance as well as hematological, biochemical and histopathological parameters in the liver were analyzed. After the feeding period, the fish were subjected to heat/dissolved oxygen-induced stress (32°C/2.3mg·L−1) for three days, when the same hematological and biochemical parameters were evaluated. The toxicity of dietary copper supplementation impaired the growth performance (P<0.05) of fish fed 1000mgCu·kg−1 and 1500mgCu·kg−1 and influenced the hematological profile after the feeding period (P<0.05). The ceruloplasmin enzyme exhibited higher activity after heat stress. Histopathological changes in the fish liver were observed in all of the treatments, regardless of the dietary copper supplementation. Fish fed diets without copper supplementation showed the lowest value of iron in the liver, which differed significantly (P<0.05) from the levels in fish fed the highest copper supplementations. The highest levels of copper supplementation resulted in the highest values of copper concentration in the liver, whereas supplementation with 0–8mgcopper/kg diet did not change the copper concentrations in the liver. Therefore, considering the fish growth, health, ceruloplasmin activity and liver histopathology, it can be concluded that levels of available copper close to the required amount were sufficient to ensure the growth and health of Nile tilapia, even under the stress condition, whereas an excess of this mineral in the diet impaired the growth and health of this species. Statement of relevanceCopper is an essential micro mineral, and its requirement has been established for some fish species. However, there is a lack of information on the effects of dietary copper supplementation on fish subjected to stress. Therefore, it is important to understand how fish fed graded levels of copper respond under stress that is usual in fish farms. Thus, economic losses can be avoided.

Effects of dietary copper supplementation on nutrient digestibility, serum biochemical indices, and growth rate of young female mink (Neovison vison)

The objective of this study was to determine whether nutrient digestibility and growth performance of mink were affected by different dietary copper levels. Ninety-six 60-day-old healthy female minks were randomly assigned to 8 treatment groups with 12 animals in each group and fed a diet supplemented with either 0, 4, 8, 16, 32, 64, 128 or 256 mg/kg copper as CuSO&lt;sub&gt;4 &lt;/sub&gt;&amp;times; 5H&lt;sub&gt;2&lt;/sub&gt;O, respectively. Our data showed that body weight and average daily gain increased (linear and quadratic, P &amp;lt; 0.05) as Cu increased in the diet, the highest body weight and average daily gain were seen in the Cu32 group. Feed : gain ratio responded in a linear (P = 0.0025) fashion with increasing level of Cu, the lowest feed : gain ratio was seen in the Cu64 group. Digestibility of ether extract responded in a linear (P = 0.0190) fashion with increasing level of Cu. There were no differences in apparent digestibility of dry matter, CP, and gross energy among groups (P &amp;gt; 0.05). N retention linearly (P = 0.0363) responded to increasing levels of Cu. Glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase increased (linear and quadratic, P &amp;lt; 0.05) as Cu increased in the diet; the highest glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase were seen in the Cu256 group. Total protein of the minks was similar among the treatments, however, albumin in serum responded in a linear (P = 0.0370) and quadratic (P = 0.0049) fashion with increasing level of Cu. The activity of ceruloplasmin responded in a linear (P = 0.0001) and quadratic (P = 0.0203) fashion with increasing level of Cu. The activity of Cu-Zn superoxide dismutase responded in a linear (P = 0.0010) fashion with increasing level of Cu. Our results indicate that supplemental Cu plays an important role in the growth performance of mink, helping young female mink digest and efficiently utilize added dietary fat. &amp;nbsp;

High Lever Dietary Copper Promote Ghrelin Gene Expression in the Fundic Gland of Growing Pigs

This experiment was conducted to examine the effect of dietary copper supplementation on ghrelin mRNA expression level in the fundic gland of growing pigs. A total of 45 crossbred pigs were randomly assigned to three groups of 15 pigs, five replicates of three animals comprised each group. Pigs were allocated to diets that contained 5mg/kg copper (as the control group), 125mg/kg copper sulfate, or 125mg/kg copper methionine. At the end of the experiment, five pigs were selected at random from each group, slaughtered, and collected the fundic gland for determination of ghrelin mRNA expression level. The results showed that average daily gain, average daily feed intake, absolute weight, serum growth hormone (GH) concentration, and ghrelin mRNA level were higher in pigs fed the diets with 125mg/kg copper methionine and 125mg/kg copper sulfate (P < 0.05), than in pigs fed a diet with 5mg/kg copper. These data suggest that high dietary copper (125mg/kg) appears to increase feed intake and promote weight gain by enhancing the secretion of GH and ghrelin mRNA level in growing pigs.

Effects of dietary copper supplementation on production performance and plasma biochemical parameters in broiler chickens

1. A study was conducted to estimate the effect of copper (Cu) supplementation on growth performance and biochemical profiles of blood and meat in broiler chickens. 2. A total of 240 d-old broiler chicks (Vencobb-100) were randomly divided into 12 groups, each of 20 chicks (4 treatments × 3 replicates). 3. The basal diet (T1) contained 215 g kg−1 crude protein (CP), 12·76 MJ kg−1 ME, 32 g kg−1 total calcium and 5 g kg−1 total phosphorus. T2, T3 and T4 were formulated to contain an additional 75, 150 and 250 mg Cu kg−1 diet, respectively. Copper sulphate pentahydrate (CuSO4, 5H2O) was used as the source of Cu. 4. Significant reductions in plasma total cholesterol and triglyceride, and an elevated concentration of HDL-cholesterol, were observed in the chickens fed with 250 mg Cu kg−1 (T4) of feed at the 3rd and 6th week of the experiment. Total cholesterol in meat decreased significantly in the birds fed with dietary Cu at 250 mg kg−1 (T4) of feed. 5. Growth performance was measured in terms of live weight gain, cumulative feed intake and feed conversion ratio at the end of d 21 and d 42 of the experiment, and the result was found to be commercially beneficial for the chickens receiving 150 mg Cu kg−1 (T3) of diet. The concentration of Cu in breast muscle and liver increased significantly at the end of experiment. 6. From this study it can be concluded that supplementation with dietary Cu may be beneficial for production performance and plasma biochemical characteristics of broiler chickens.

The effects of dietary copper supplementation on oxidative and antioxidant systems in broiler chickens

espanolEl estudio fue disenado para estudiar los efectos in vivo de la suplementacion dietetica con cobre sobre los sistemas oxidativos y antioxidantes de los eritrocitos y el higado de broilers. Las aves fueron sometidas a una dieta comercial (grupo control, n= 20) o suplementada con 250 mg CuSO4/kg dieta (grupo experimental, n= 20) durante 6 semanas. En los eritrocitos y tejido hepatico, se evaluo, empleando tecnicas consolidadas, la sobrecarga de cobre, la peroxidacion oxidativa de los lipidos (LPO), concentracion de glutation (GSH), actividad de los enzimas antioxidantes, super oxido dismutasa (SOD) y catalasa (CAT). La exposicion oral al cobre, durante 6 semanas, aumento (p EnglishThis study was designed to investigate the in vivo effects of dietary copper supplementation on the oxidative and antioxidant systems in the erythrocyte and liver of broiler chickens. Birds were exposed to commercially prepared diet (control group, n= 20) or commercial diet supplemented with 250 mg CuSO4/kg diet (experimental group, n= 20) for 6 weeks. The copper burdens, oxidative lipid peroxidation (LPO), glutathione (GSH) concentration, activity of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were evaluated in the erythrocyte and hepatic tissues using well established techniques. Oral exposure to copper for a period of 6 weeks significantly (p

Effect of High Dietary Copper on Somatostatin and Growth Hormone-Releasing Hormone Levels in the Hypothalami of Growing Pigs

This experiment was conducted to examine the effect of dietary copper supplementation on somatostatin (SS) and growth hormone-releasing hormone (GHRH) mRNA expression levels in the hypothalami of growing pigs. A total of 45 crossbred pigs were randomly assigned to three groups of 15 pigs each; five replicates of three animals comprised each group. Pigs were allocated to diets that contained 5 mg/kg copper (control), 125 mg/kg copper sulfate, or 125 mg/kg copper methionine. At the end of the experiment, five pigs were selected at random from each group and slaughtered, and hypothalami were collected for determination of SS and GHRH mRNA expression levels. The results showed that the SS expression levels were lower and the GHRH levels were higher in pigs fed the diets with 125 mg/kg copper methionine (P<0.05) and 125 mg/kg copper sulfate (P<0.05), respectively, than in pigs fed the diet with 5 mg/kg copper. Furthermore, the relationship between SS mRNA and GHRH mRNA abundance had a significantly negative correlation (P<0.05). The data indicated that high dietary copper could enhance GHRH mRNA expression levels and suppress SS mRNA expression levels in the hypothalami of pigs. High lever dietary copper (125 mg/kg copper sulfate or 125 mg/kg copper methionine) increased pigs' growth performance and feed efficiency but had no significant effect on daily feed intake; 125 mg/kg copper sulfate or 125 mg/kg copper methionine at the same lever had no difference on growth promoting in pigs.

Effect of high dietary copper on weight gain and neuropeptide Y level in the hypothalamus of pigs

An experiment was performed to examine the effect of dietary copper supplementation on weight gain, neuropeptide Y (NPY) concentration and NPY mRNA expression level in the hypothalamus of pigs. Forty-five crossbred pigs were randomly assigned to three groups of 15 pigs, each comprising five replicates of 3 animals. Pigs were allocated to diets that contained 10 mg/kg (as a control), 125 and 250 mg/kg copper as CuSO 4. Live weight gain and feed conversion efficiency was determined at the end of the experiment and five pigs, selected at random from each group, were slaughtered and the hypothalami collected for determination of NPY concentration and NPY mRNA expression level. The results showed that average daily gain (ADG) and average daily feed intake (ADFI) were higher and feed:gain (F:G) ratio was lower in pigs fed the diets with 125 and 250 mg/kg copper ( P<0.05), respectively, than in pigs fed a diet with 10 mg/kg copper, but that there was no statistically significant difference in growth performance between animals of the 125 mg/kg and the 250 mg/kg copper groups. Furthermore, pigs fed diets with 125 and 250 mg/kg copper had higher NPY concentrations and NPY mRNA expression levels in their hypothalamus than control animals. The data indicated that 125 and 250 mg/kg copper gave similar responses in terms of weight gain, whilst high dietary copper could enhance NPY concentration and NPY mRNA expression level in the hypothalamus of pigs. High dietary copper appears to increase feed intake and promote weight gain by enhancing NPY concentration and NPY mRNA expression level in the hypothalamus of pigs.

The effect of dietary copper supplementation on fatty acid profile and oxidative stability of adipose depots in Boer × Spanish goats1

A feeding trial was designed to examine the effects of copper sulfate pentahydrate (CuSO(4).5H(2)O) on the fatty acid composition and oxidative stability in muscle and adipose tissues of Boer x Spanish goat kids. Fifteen (n = 5 per treatment) goats were fed 0, 100, or 200 mg of supplemental Cu per day as copper sulfate for 98 d. The animals were slaughtered, and LM, s.c. adipose from the sternal region, and mesenteric adipose tissues were collected. Total lipids were extracted with chloroform:methanol (2:1), methylated and isolated via GLC from all tissues. The subsequent peaks were then positively identified by mass spectrometry. Thiobarbituric acid-reactive substances were measured also. In s.c. adipose, dietary Cu significantly decreased C14:0 (P = 0.03) and C16:0 (P = 0.01). In muscle, C15:0 (P = 0.03) was linearly increased by Cu. Dietary Cu supplementation did not influence oxidative stability in goat muscle or s.c. adipose. Copper supplementation at 200 mg/d resulted in a significant increase in malondialdehyde in mesenteric adipose (P = 0.01) compared with the 0 or 100 mg/d groups. These results indicate that lipid composition may differ from depot to depot and that depending on the depot, dietary Cu seems to elicit a variable response on the fatty acid composition.

Effects of Dietary Copper Supplementation and Copper Source on Digesta pH, Calcium, Zinc, and Copper Complex Size in the Gastrointestinal Tract of the Broiler Chicken

An experiment was conducted to study the effects of high dietary Cu and Cu source on the pH of digesta from the gizzard, duodenum + jejunum, ileum, and complex size of Ca, Zn, and Cu in the duodenum + jejunum digesta of broiler chickens. Ross 308 male broiler chicks were randomly assigned to 32 cages and fed 1 of 4 treatments: control, 250 ppm Cu from sulfate, 250 ppm Cu from lysinate, and 250 ppm tribasic Cu from chloride from 15 to 21 d of age. Copper supplementation and Cu source had no effects on pH of gizzard or duodenum + jejunum contents. Copper supplementation, however, increased the pH of the ileal contents (P < 0.05) but was not affected by Cu source. Neither Cu supplementation nor Cu source had significant effects on the solubility of Ca in the duodenum + jejunum contents, and the portions of Ca existing in different soluble complex sizes: >100,000, 100,000 to 30,000, 30,000 to 5,000, and <5,000 molecular weight (MW) in the duodenum + jejunum digesta. About 80% of soluble Ca, Cu, and Zn was associated with either large complexes (>100,000 MW) or small complexes (<5,000 MW). The solubility of supplemental Cu in digesta was from 59 to 61% (P < 0.05), but solubility was not affected by Cu source. No effects on portions of Cu existing in different sizes of complexes in the supernatant were noted. Copper lysinate decreased the Zn solubility in the digesta (P < 0.05), but Cu sulfate and tribasic Cu chloride supplementation did not. Copper supplementation increased (P < 0.05) the percentage of Zn associated with large complexes (>100,000 MW) and decreased (P < 0.05) the percentage of Zn associated with small complexes (<5,000 MW; P < 0.05), thereby suggesting an antagonism between Cu and Zn.

Beneficial Effects of Dietary Copper Supplementation on Serum Lipids and Antioxidant Defenses in Rats

Background: A nutrition experiment was utilized to investigate the effects of two levels of dietary copper (Cu) supplementation on lipid profile and antioxidant defenses in serum of rats. Methods: Male Wistarrats (180–200 g; n = 10) were divided into three groups: control group (A), fed a basal diet with 6 µg Cu/g, and rats fed a basal diet with Cu (CuSO₄) supplementation from aqueous solutions, for 4 weeks at the final concentrations of 2 mg Cu/rat (B) and 3 mg Cu/rat (C). Results: No significant changes were observed in final body weight, body weight gain, food consumption, total serum protein and high-density lipoprotein. Cu supplementation reduced the triacylglycerol (TG), total cholesterol and low-density lipoprotein (LDL-C). The LDL-C/TG ratio and total antioxidant substances (TAS) were higher in (B) and (C) groups than in (A) group. There was a positive correlation between Cu supplementation and ceruloplasmin levels. The markers of oxidative stress, lipid hydroperoxide and lipoperoxide were decreased with Cu supplementation. No alterations were observed in superoxide dismutase, indicating saturation of Cu enzyme site. The glutathione peroxidase activities (GSH-Px) were increased in both Cu-supplemented groups. Considering that a copper-selenium interaction can affect mineral availability of both elements, the effects of Cu on TAS and GSH-Px activities were associated with increased selenium disposal. Conclusions: Dietary Cu supplementation had beneficial effects on lipid profile by improving endogenous antioxidant defenses and decreasing the oxidative stress in vivo.

Effect of dietary copper supplementation on cell composition and apoptosis in atherosclerotic lesions of cholesterol-fed rabbits

We have previously shown that dietary copper supplementation modulates the formation of atherosclerotic lesions in the cholesterol-fed rabbit. In the present study, we have investigated the effects of copper supplementation on the cellular composition and characteristics of atherosclerotic lesions in cholesterol-fed NZW rabbits. Rabbits received a 1% cholesterol diet with or without 0.02% copper acetate (containing 12 and 0.3 mg copper per 100 g diet, respectively) for 12 weeks. The tunica intima was significantly smaller in the animals receiving copper supplements (0.016±0.005 vs. 0.068±0.019 mm 2, P<0.05) and this was accompanied by a significant increase in aortic copper content (4.0±0.8 vs. 1.8±0.2 μg/g tissue, P<0.05). The percentage area staining for smooth muscle cells (HHF-35 positive) was significantly lower in the intima of animals receiving copper supplements (7.13±1.02 vs. 9.72±0.82%, P<0.05). However, there were no significant differences in area staining for macrophages (RAM-11 positive) between groups (22.6±7.9 vs. 23.3±4.9%). There were also significantly fewer apoptotic cells (0.96±0.33 vs. 2.54±0.56%, P<0.005) in the aortic intima from animals supplemented with copper, but no difference in the number of proliferating cells. However, there was a reduction in intimal collagen staining (Sirius red positivity) in the animals receiving a copper supplement. Taken together, these data show that dietary copper can significantly affect the composition and progression of atherosclerotic lesions.

Effect of dietary copper on selenium toxicity in Fischer 344 rats.

The purpose of this study was to investigate the ameliorating effects of dietary copper supplementation on selenium toxicity. Nine groups (n = 6) of weanling Fischer 344 female rats were randomly assigned to treatment groups and fed diets containing nontoxic levels of copper as CuCl2 and/or selenium as selenite or selenocystamine. Weight gain, liver and spleen weights, plasma lipid peroxidation, and liver selenium and copper content were analyzed after the 6-wk treatment period. Concentrations of up to 10 times the daily lethal dose of dietary selenium were well tolerated in rats supplemented with dietary copper. As the dietary level of selenium was increased, the ratio of selenium to copper measured in the liver decreased. In the groups of rats in which dietary copper supplementation was absent and dietary selenium was supplemented, copper stores in the liver remained unchanged from control values. Copper's protective effects from dietary selenium toxicity may come from the formation of a copper-selenide complex that renders both selenium and copper metabolically unavailable and nontoxic.

Dietary copper supplementation reduces atherosclerosis in the cholesterol-fed rabbit

There has been considerable debate about how copper status may affect the biochemical and cellular processes associated with atherogenesis. In the present study we have attempted to address this issue directly by investigating the effects of dietary copper supplementation on processes likely to contribute to atherogenesis, using the cholesterol-fed New Zealand White rabbit model. Age matched rabbits ( n=16) were fed a 0.25–1% cholesterol diet to maintain plasma cholesterol concentrations at approximately 30 mmol/l. Eight of these animals also received 0.2% copper acetate. Control animals ( n=8) received rabbit chow without supplements. After 13 weeks on the experimental diets the animals were killed. Integrated cholesterol levels were similar for the cholesterol-fed animals (31.1±2.5 vs. 29.9±1.9 mmol/l weeks; P>0.05). Although integrated plasma copper levels were higher in the animals receiving the copper supplements, these did not differ significantly (19.0±4.8 vs. 15.1±2.9 μmol/l weeks; P>0.05). Tissue concentrations of copper were higher in the copper fed animals compared to those on cholesterol alone in aortic (4.0±0.75 vs. 1.8±0.2 μg/g wet tissue; P<0.05), carotid artery (11.4±3.5 vs. 4.9±0.9 μg/g wet tissue; P<0.05), and hepatic (332.5±28.6 vs. 3.3±1.1 μg/g wet tissue; P<0.0001) samples. The concentration of copper within the carotid artery was also significantly higher than that within the aorta (7.5±1.8 vs. 2.4±0.4 μg/g wet tissue; P<0.05). In animals fed a normal rabbit chow aortic, carotid and hepatic copper concentrations were 3.7±0.8, 9.4±3.4, and 5.0±1.6 μg/g, respectively. These values did not differ significantly from the cholesterol-fed animals ( P>0.05). Plasma concentrations of caeruloplasmin, the major copper carrying protein, were estimated as plasma ferroxidase activity and were similar for the groups ( P>0.05), as were aortic superoxide dismutase activity levels ( P>0.05). Copper supplementation was associated with increased mononuclear cell adhesion to the endothelium of the carotid endothelium, with 2.6±0.3 adherent monocytes/1000 endothelial cells in the cholesterol plus copper-fed animals compared to 1.3±0.3 in the cholesterol-fed group ( P=0.0.0006), and 0.1±0.1 in the control animals ( P<0.002). This may reflect the higher concentrations of copper found within the carotid artery. Histology of the thoracic aorta at the level of the third and sixth intercostal arteries, showed that copper supplementation was associated with significantly smaller intimal lesions ( P<0.05 and P<0.01, respectively). These data suggest that copper supplements possibly inhibit the progression of atherogenesis.

Effects of dietary copper supplementation of rats on the occurrence of metallothionein-I in liver and its secretion into blood, bile and urine.

The appearance and excretion of metallothionein-I (MT-I) was studied in rats given a diet containing 1000 mg of Cu/kg for several weeks. No significant increase in MT-I concentrations in liver, plasma or bile was detected in rats with liver copper concentrations less than 600 micrograms of Cu/g fresh wt. Above this concentration, liver MT-I concentrations increased in proportion to the increase in hepatic copper content. Plasma and bile MT-I concentrations were directly related to those in the liver and were about 10 times those in normal rats. Urinary MT-I concentration also increased 10-fold within 1 week. Fractionation of bile and urine on Sephadex G-50 revealed the presence of monomeric MT-I and a range of possible degradation products of the isoprotein.