Plasma Copper Concentrations Research Articles

Determination of iron, copper, zinc, magnesium and selenium in plasma and erythrocytes in neurosurgical patients

A direct method for determination of Fe, Cu, Zn, Mg and Se in erythrocytes was developed. The aim of the present study was to establish a method for examining perioperative levels of the above mentioned elements simultaneously in erythrocytes and plasma by atomic absorption spectrophotometry in 11 patients undergoing neurosurgery for acute spinal nerve compressions because of intervertebral disk prolapses. Reference values for erythrocytes were 11.49 +/- 3.48 mmol/mmol Hb; 0.82 +/- 0.087 mmol/mmol Hb; 9.01 +/- 2.20 mmol/mmol Hb; 0.104 +/- 0.032 mmol/mmol Hb; 0.07 +/- 0.050 mmol/mmol Hb for iron, copper, zinc, magnesium, and selenium, respectively. Postoperative erythrocyte concentrations did not differ significantly compared to those obtained preoperatively and remained within the reference ranges perioperatively. For plasma the following reference values were used: 19.0 +/- 8.0 mmol/l (Fe); 20.1 +/- 8.2 mmol/l (Cu); 15.4 +/- 4.6 mmol/l (Zn); 0.9 +/- 0.15 mmol/l (Mg); 1.02 +/- 0.3 mmol/l (Se). There was a significant decrease in the concentration of copper in plasma (13.41 +/- 3.46 mmol/l, p < 0.1) and zinc (10.73 +/- 2.73 mmol/l, p < 0.1) immediately postoperative, iron (10.56 +/- 3.91 mmol/l, p < 0.1) and zinc on day 1 (11.28 +/- 1.88 mmol/l, p < 0.10), and a significant postoperative increase of copper on day 5 (18.81 +/- 3.97 mmol/l, p < 0.1), postoperatively. The mean plasma concentrations of iron, copper, zinc magnesium and selenium remained within the reference ranges during the entire period.

Plasma zinc and copper concentrations after orthotopic liver transplantation

Plasma zinc and copper concentrations after orthotopic liver transplantation

Superoxide dismutase activity and zinc and copper concentrations in Parkinson’s disease

Although several hypotheses are currently being investigated the cause of Parkinson’s disease (PD) is still unknown. The aim of this study was to determine red cell copper/zinc-superoxide dismutase (Cu/Zn-SOD) activity and copper and zinc concentrations both in plasma and in red cell in PD. In this preliminary assay, 30 patients with PD the mean age of 64 were studied. Additionally, a second group of older individuals without PD mean age of 61, were recruited to the study. The patient group was compared with the other group according to their red cell Cu/Zn-SOD activities, and plasma and red cell copper, zinc concentrations. Red cell Cu/Zn-SOD activity was measured spectrophotometrically while plasma and red cell copper, zinc concentrations were determined by atomic absorption spectrophotometer. The results were analysed by ‘Student t-test’ statistically. The results showed that red cell Cu/Zn-SOD activities and red cell copper and zinc and also plasma copper concentrations of the PD patients increased compared to older individuals without PD. These findings suggested that possibility of oxidative stress in PD was reflected on the blood including the red cell and plasma parameters.

Antioxidant enzyme activities and trace element concentrations in ischemia-reperfusion.

In this study, we investigated the impact of ischemia-reperfusion on antioxidant enzyme activities and trace element concentrations. For this purpose, ischemia was initiated by clamping superior mesenteric artery of Wistar (albino) rats for 30 min, followed by reperfusion for 20 min. Immediately after reperfusion, blood samples were taken and examined for red cell copper-zinc superoxide dismutase (Cu-Zn-SOD), catalase (CAT), and glutathione peroxidase (GPx) activities spectrophotometrically and plasma zinc, copper, and magnesium concentrations by atomic absorption spectrophotometer. In the ischemia-reperfusion group, red cell Cu-Zn-SOD activity and plasma zinc and copper concentrations were increased significantly (p < 0.001) when compared to the control group; however, the increases in GPx activity and plasma magnesium concentration were not significant (p > 0.05). We also found a significant (p < 0.01) decrease in catalase activity. Free radicals released as a consequence of ischemia-reperfusion caused significant alterations in antioxidant enzymes and in the concentrations of trace elements.

Milk Ceruloplasmin and Its Expression by Mammary Gland and Liver in Pigs

Concentrations of ceruloplasmin and copper in milk and blood plasma, the nature of milk ceruloplasmin, and the effects of lactation and gestation on these parameters, as well as the expression of ceruloplasmin mRNA by the mammary gland, were examined in pigs. As seen previously in humans, ceruloplasmin and copper concentrations in sow milk were much higher a few days after birth than 1 month later, averaging 26.5 and 6.6 mg ceruloplasmin/L (by immunoassay) and 1.67 and 0.34 mg total Cu/L, on days 3 and 33 postpartum, respectively. Values for ceruloplasmin oxidase activity (measured with p-phenylene diamine) were 7.8 and 1.3 nmol/min/L, respectively. Daily milk ceruloplasmin production went from 61 to 22 mg/day and daily copper output from 38 to 12 mg/day. In contrast, there was little or no variation in serum ceruloplasmin concentration during lactation or gestation, although total plasma copper was high at the end of gestation. Milk ceruloplasmin was of the same apparent size as serum ceruloplasmin, as determined by SDS–PAGE and immunoblotting, and ceruloplasmin mRNAs of liver and mammary gland were indistinguishable by Northern analysis and RT-PCR of the various exons. Expression of total RNA and ceruloplasmin mRNA, as detected in biopsies of mammary gland, increased markedly upon onset of lactation and then declined during the next month in conjunction with a drop in milk ceruloplasmin production. The results indicate that milk ceruloplasmin, while being the same protein as in plasma, is not derived from the plasma but is produced by the mammary gland.

Phosphate binders do not compromise the copper status of adult renal disease patients on hemodialysis.

The effects of phosphate binder therapies (calcium carbonate, calcium acetate, or aluminum hydroxide) on copper status were assessed in 88 adult patients with end-stage renal disease on hemodialysis. Subjects were divided into two groups based on binder therapy compliance as specified by medical criteria established by the Health Care Financing Administration. Binder compliant subjects (n = 62), aged 59.7+/-12.2 yr, maintained serum phosphorus concentrations of 3.5-6.0 mg/dL. Noncompliant subjects (n = 26), aged 54.2+/-13.8 yr, had serum phosphorus concentrations > 6.0 mg/dL. Mean plasma and red blood cell (RBC) copper, serum ceruloplasmin, and erythrocyte superoxide dismutase activity did not differ between binder compliant and noncompliant subjects. Mean RBC copper, plasma copper, and serum ceruloplasmin concentrations of hemodialysis subjects were within normal limits, despite copper intakes of less than two-thirds of the lower limit of the Estimated Safe and Adequate Daily Dietary Intakes for copper. The phosphate binder therapies (calcium carbonate, calcium acetate, and/or aluminum hydroxide) had no effect on the copper status of patients with end-stage renal disease on hemodialysis.

Measurement and Correlation of Liver, Kidney and Plasma Copper Concentrations and Haemoglobin in Holstein Cattle

Badiei, K. and Darboui, M. 1999. Measurement and correlation of liver, kidney and plasma copper concentrations and haemoglobin in Holstein cattle. J. Appl. Anim. Res., 15: 131–136. Haemoglobin, liver, kidney and plasma copper concentrations were measured in 40 Holstein cattle (20 bulls and 20 non-pregnant cows) aged, between 3 to 4 years in Fars Industrial Meat Complex. The mean copper levels as measured by atomic absorption flame spectrophotometry in liver, kidney and plasma were 57.97, 7.04 and 1 ppm, respectively. There were no significant differences between the two sexes (P>0.05). There was a low correlation (r= 0.19, P<0.05) between liver and plasma copper concentration. The correlation between the copper concentration of plasma and kidney was (r = 0.20, P<0.05). Although there was a significant correlation between haemoglobin and plasma copper concentration it could, not be explained.

Folate and homocysteine metabolism in copper-deficient rats

To investigate the effect of copper deficiency on folate and homocysteine metabolism, we measured plasma, red-cell and hepatic folate, plasma homocysteine and vitamin B-12 concentrations, and hepatic methionine synthase activities in rats. Two groups of male Sprague–Dawley rats were fed semi-purified diets containing either 0.1 mg (copper-deficient group) or 9.2 mg (control group) of copper per kg. After 6 weeks of dietary treatment, copper deficiency was established as evidenced by markedly decreased plasma and hepatic copper concentrations in rats fed the low-copper diet. Plasma, red-cell, hepatic folate, and plasma vitamin B-12 concentrations were similar in both groups, whereas plasma homocysteine concentrations in the copper-deficient group were significantly higher than in the control group ( P<0.05). Copper deficiency resulted in a 21% reduction in hepatic methionine synthase activity as compared to the control group ( P<0.01). This change most likely caused the increased hepatic 5-methyltetrahydrofolate and plasma homocysteine concentrations in the copper-deficient group. Our results indicate that hepatic methionine synthase may be a cuproenzyme, and plasma homocysteine concentrations are influenced by copper nutriture in rats. These data support the concept that copper deficiency can be a risk factor for cardiovascular disease.

Effect of reducing the phytate content and of partially hydrolyzing the protein in soy formula on zinc and copper absorption and status in infant rhesus monkeys and rat pups

Although soy formulas have been designed to meet the nutrient requirements of human infants, they also contain phytate, which may negatively affect trace element absorption. We evaluated the effect of removing phytate on zinc and copper absorption and status in infant rhesus monkeys and suckling rat pups and evaluated differences between intact and partially hydrolyzed soy protein. In monkeys, regular and low-phytate soy formulas were fed exclusively for 4 mo and whole-body absorption and retention of 65Zn, 67Cu, 59Fe, 54Mn, and 47Ca were determined at different time points with a whole-body counter. Subsequently, zinc and copper absorption from several human infant formulas and the effect of phytate concentration were evaluated in suckling rat pups by using 65Zn and 64Cu. Finally, infant rhesus monkeys were fed low-phytate formulas with intact or hydrolyzed soy protein for 4 mo and plasma zinc and copper were measured monthly. In the first monkey study, zinc absorption at 1 mo was higher from low-phytate soy formula (36%) than from regular soy formula (22%), whereas there was no significant difference between groups in the absorption of other minerals. Plasma copper was significantly lower in monkeys fed low-phytate soy formula from 2 to 4 mo. In rat pups, zinc absorption was significantly higher from low-phytate soy formula (78%) than from regular soy formula (51%) and hydrolysis of the protein had no significant effect. Phytate content or protein hydrolysis did not significantly affect copper absorption. In the second monkey study, plasma copper concentrations were highest in monkeys fed the low-phytate, hydrolyzed-protein soy formula. Reducing the phytate content and partially hydrolyzing the protein in soy formula had a beneficial effect on zinc and copper absorption and status in infant rhesus monkeys.

Biochemical and Physiological Responses in Atlantic Salmon ( Salmo salar) Following Dietary Exposure to Copper and Cadmium

Three experiments were conducted with Atlantic salmon ( Salmo salar) to assess the effects of dietary exposure to copper and cadmium. The results presented here provide an overview, details of each experiment will be published in full elsewhere. In the first experiment, salmon parr exposed for four weeks to 35 and 700 mg Cu kg −1 diet had significantly elevated intestinal copper concentrations, cell proliferation (PCNA) and apoptosis rates compared to control fish. No differences were observed in gill or plasma copper concentrations among the groups. In contrast to the controls, the Cu exposed groups did not grow significantly during the exposure period. The second experiment (three months exposure) was conducted to assess the effects of dietary copper (control, 35, 500, 700, 900 or 1750 mg Cu kg −1 diet) on growth and feed utilization in salmon fingerlings. Growth was significantly reduced after three months exposure to dietary Cu concentrations above 500 mg kg −1. Similarly, copper body burdens were significantly higher in fish exposed to elevated dietary copper concentrations (above 35 mg Cu kg −1 diet). In the third experiment, salmon parr were exposed to one of six dietary cadmium concentrations (0, 0.5, 5, 25, 125 or 250 mg Cd kg −1 diet) for four months. Cadmium accumulated in the liver>intestine>gills of exposed fish. Rates of apoptosis and cell proliferation in the intestine increased following exposure to dietary cadmium. Exposure to elevated concentrations of dietary cadmium had no effect on growth in salmon parr. Results from these studies indicate that cellular biomarkers have potential as early warning signs of negative effects on the overall fitness of an organism.

Efficacy of Copper Oxide Needles in Preventing Copper Deficiency in Cattle

The purpose of this study was to evaluate the hypothesis that a single dose of copper oxide needles administered to cattle at the beginning of the grazing period would sustain plasma copper concentrations and prevent growth depression associated with copper deficiency for the duration of the grazing period. Comparisons of efficacy were made against the traditional treatment methods of copper glycinate injection and copper supplementation in salt in two trials involving age groups most at risk for clinical copper deficiency calves and replacement heifers. High pasture molybdenum concentrations with Cu:Mo ratios below 5:1 were present at both trial locations.

Copper, Ceruloplasmin and Superoxide Dismutase in Patients with Alzheimer’s Disease

The copper-containing enzyme superoxide dismutase (SOD) is a key enzyme in suppressing the amounts of superoxide anion radicals. Ceruloplasmin, the copper-transporting protein in plasma, also possesses an important redox capacity. In this study the levels of copper and ceruloplasmin as well as SOD-activity and ceruloplasmin oxidative activity were analyzed in order to throw some light on possible defects in copper mechanisms in patients diagnosed with Alzheimer’s disease (AD). The study included 44 patients with AD and their healthy age- and gender-matched controls. No difference of significance was seen when comparing the copper or ceruloplasmin concentration in plasma of AD patients to that of their paired controls. The SOD activity in red blood cells was significantly lower in the patients than in their controls (p = 0.019). The ceruloplasmin oxidative activity in plasma of Alzheimer’s patients was greatly reduced as compared to that of age- and gender-matched controls and the difference was highly significant (p = 0.0005). Ceruloplasmin activity and SOD activity were not found to be intrinsically correlated. It was postulated that reduced oxidative activity of ceruloplasmin in plasma might be either a cause or a consequence of AD and that reduced SOD activity might further add to the oxidative disturbances in AD due to defective ceruloplasmin activity.

Trace element supplementation modulates pulmonary infection rates after major burns: a double-blind, placebo-controlled trial

Infections remain the leading cause of death after major burns. Trace elements are involved in immunity and burn patients suffer acute trace element depletion after injury. In a previous nonrandomized study, trace element supplementation was associated with increased leukocyte counts and shortened hospital stays. This randomized, placebo-controlled trial studied clinical and immune effects of trace element supplements. Twenty patients, aged 40 ± 16 y (- ± SD), burned on 48 ± 17% of their body surfaces, were studied for 30 d after injury. They consumed either standard trace element intakes plus supplements (40.4 μmol Cu, 2.9 μmol Se, and 406 μmol Zn; group TE) or standard trace element intakes plus placebo (20 μmol Cu, 0.4 μmol Se, and 100 μmol Zn; group C) for 8 d. Demographic data were similar for both groups. Mean plasma copper and zinc concentrations were below normal until days 20 and 15, respectively (NS). Plasma selenium remained normal for group TE but decreased for group C (P < 0.05 on days 1 and 5). Total leukocyte counts tended to be higher in group TE because of higher neutrophil counts. Proliferation to mitogens was depressed compared with healthy control subjects (NS). The number of infections per patient was significantly (P < 0.05) lower in group TE (1.9 ± 0.9) than in group C (3.1 ± 1.1) because of fewer pulmonary infections. Early trace element supplementation appears beneficial after major burns; it was associated with a significant decrease in the number of bronchopneumonia infections and with a shorter hospital stay when data were normalized for burn size. Am J Clin Nutr 1998;68:365–71.

Changes in the Concentrations of Plasma Selenium and Selenoproteins after Minor Elective Surgery: Further Evidence for a Negative Acute Phase Response?

The acute phase plasma protein response is part of the complex series of physiological, hematological, and biochemical events that constitute the inflammatory response after tissue injury or infection. The magnitude and duration of the response are related to the nature and severity of the injury and the presence of sepsis (1). We have previously related alterations in plasma iron, transferrin, zinc, albumin, copper, and ceruloplasmin concentrations after major surgery to a marked rise in plasma C-reactive protein (CRP) concentration (2). In both acute (3)(4) and chronic (5) illnesses, the plasma concentration of selenium also decreases in proportion to the magnitude of the inflammatory response. There is concern about the decline in dietary intake of selenium in some areas of the world (6), because the antioxidant activities of several selenoproteins may be important in preventing free radical damage (7). If plasma selenium concentrations decrease during an inflammatory response, independently of dietary intake, then this would have important implications for the interpretation of the plasma selenium values reported in a wide range of illnesses. In this study, total plasma selenium concentration and changes in plasma selenoproteins after minor elective surgery (inguinal hernia repair) were determined and related to the accompanying alterations in plasma CRP. Ten male patients (mean age, 51 years; range, 18–90 years) requiring inguinal hernia repair were recruited to the study. All patients were healthy before surgery, and none were taking any relevant medication. Samples of head hair and toe nails (80–100 mg) were obtained 24 h before surgery as a measure of long-term selenium nutritional status, along with venous blood collected into plain (10 mL) and lithium heparin tubes (20 mL). Blood samples were taken on the mornings of day 1 and day 6 after surgery. None of the patients …

Copper intake and assessment of copper status

The diagnosis of marginal copper deficiency has not been perfected despite an increased understanding of the physiologic roles of copper. The use of nonstandardized procedures and the effects of factors other than copper nutriture have impeded identification of an ideal indicator of copper nutritional status in humans. A review of studies of experimental copper deprivation conducted in adult humans over the past 12 y indicated that between 1.0 and 1.25 mg Cu/d is needed by adults for copper maintenance for periods of up to 6 mo and that < or = 2.6 mg Cu/d for periods of up to 42 d is not sufficient for recovery from copper deprivation. Copper-containing enzymes in blood cells, such as erythrocyte superoxide dismutase and platelet cytochrome-c oxidase, may be better indicators of metabolically active copper and copper stores than plasma concentrations of copper or ceruloplasmin because the enzyme activities are sensitive to changes in copper stores and are not as sensitive to factors not related to copper nutriture.

Effect of copper supplementation on the copper status of pasture-fed young Thoroughbreds.

The effect of copper supplementation of pasture fed mares and foals on the copper status of the foals, in terms of plasma, soft tissue and bone copper concentrations and caeruloplasmin activity, was investigated. Twenty-one Thoroughbred foals from either control mares (n = 9), or copper-supplemented mares (n = 12) were divided randomly into control (pasture only, n = 10) or supplemented (pasture and oral copper sulphate, n = 11) groups. The pasture diet was grazed by all animals, and contained 4.4-8.6 mg Cu/kg dry matter (DM). The copper supplement for the mares contained copper sulphate equivalent to 0.5 mg Cu/kg liveweight (LW)/day. This daily dose was converted to allow administration as a thrice weekly dose (i.e. multiplied by 7/3) which was given for 13-25 weeks prior to foaling. The supplemented foals, also dosed 3 times a week, received 0.2 mg Cu/kg LW/day at age 21 days, which was increased to 0.5 mg Cu/kg LW/day at 49 days and was continued at this level until euthanasia at 150 days. Foal plasma copper concentration and caeruloplasmin activity increased from birth to 21 days post partum and then plateaued at a concentration similar to the mare, but the rise in these indices was not affected by copper supplementation of the mare or foal. Copper supplementation of the foal increased foal liver copper concentration at 150 days (P<0.03). Copper intake of diets containing approximately 8-28 mg Cu/kg DM is well reflected by liver copper concentration, but is poorly reflected by bone, other soft tissue copper concentrations and circulating copper status indices.

Copper absorption and bioavailability

The human gastrointestinal system can absorb 30-40% of ingested copper from the typical diets consumed in industrialized countries. Experimental data support the existence of a carrier-mediated transport mechanism with an affinity constant in the micromolar range. Aging probably decreases the efficiency of copper homeostasis, resulting in higher plasma copper concentrations in the elderly. Physiologic differences may account for the higher cupremia of females. Supplements of minerals with similar chemical characteristics could reduce copper absorption. This property has pharmacologic applications in Wilson disease. Manipulation of the fiber content of the diet may have an indirect effect on copper bioavailability by altering the bioavailability of mineral antagonists. Proteins and soluble carbohydrates tend to improve copper absorption and bioavailability by enhancing its solubility and intestinal bulk flow. Organic acids, other than ascorbic acid, or agents that form low-molecular-weight chelates, are likely to have a positive effect on overall copper absorption. Conditions associated with malabsorption of macronutrients and gastrointestinal disease can impair copper uptake and contribute to suboptimal copper status.

Effect of copper supplementation on copper status of pregnant mares and foals

Pregnant Thoroughbred mares (n = 21) were grazed on tall fescue pasture containing 4.4-8.6 mg Cu/kg dry matter (DM). Twelve mares were supplemented with approximately 0.5 mg Cu/kg liveweight (LW)/day as copper sulphate for the final 13-25 weeks gestation. Plasma copper concentration declined during the third trimester for all mares and was not affected by copper supplementation. Liver copper concentration of mares and foals was determined when the foals were 4-10-days-old. Copper supplementation of the mares tended to increase mare liver copper concentration (P<0.08) and increased foal liver copper concentration (P<0.01). There was a significant relationship between mare and foal liver copper concentration (P<0.001, r2 = 0.7). Increasing the copper intake of mares is effective in enhancing the copper status of foals.

Subacute and chronic toxicity studies of triethylenetetramine dihydrochloride (TJA-250) by oral administration to F-344 rats.

Triethylenetetramine dihydrochloride (trientine-2HCl, TJA-250), a copper chelating agent used to treat Wilson's disease, was administered orally to male and female F-344 rats for 4 or 8 weeks at dosages of 0, 100, 350 or 1200 mg/kg/day or for 26 weeks at dosages of 50, 175 or 600 mg/kg/day. 4 or 8-week study. Two males receiving 1200 mg/kg/day died during week 8 of treatment. In males receiving 1200 mg/kg/day during weeks 5 to 8 of treatment, body weight gain and food consumption were decreased and hunched posture and thin build were observed. During week 4 or 8 of treatment urinalysis revealed, for males receiving 100 mg/kg/day or animals receiving 350 mg/kg/day or more, increased electrolyte outputs possibly due to the hydrochloride nature of trientine-2HCl, with low plasma alkaline phosphatase activities evident in animals receiving 350 or 1200 mg/kg/day. After 4 and 8 weeks, and during 8 weeks of treatment, high lung weights and bronchiolar epithelium hypertrophy and broncho-alveolar pneumonia were recorded for animals receiving 1200 mg/kg/day, and submucosal acute inflammation within the glandular region of the stomach was recorded for males receiving 350 or 1200 mg/kg/day and in all treated female groups. 26-week study. One male receiving 175 mg/kg/day and three males receiving 600 mg/kg/day died, showing lung changes. The body weight gain of animals receiving 600 mg/kg/day was slightly decreased. Blood chemistry and urinalysis examinations showed changes similar to those indicated in the 4- or 8-week study. The low plasma copper concentrations seen in males receiving 600 mg/kg/day, the slightly low liver copper concentrations found in animals receiving 600 or 175 mg/kg/day and the high urinary copper concentrations found in all treated groups, are attributed to the pharmacological action of trientine-2HCl. Histopathology revealed a dosage-related incidence and severity of focal chronic interstitial pneumonitis accompanied by fibrosis of the alveolar walls in females receiving 175 mg/kg/day or more and all treated male groups, but no significant pathological changes in the stomach. Apart from the histological changes found in the lung, all the above changes were reversible. In conclusion, the NOAEL of trientine-2HCl in this 26-week study was considered to be 50 mg/kg/day for females and less than 50 mg/kg/day for males.

The pH dependence of silicon-iron interaction in rats.

A 2 x 2 x 3 factorial experiment was conducted to study the pH dependence of a silicon-iron interaction in vivo. The dietary treatments used in the factorial design were the following (mg/kg of diet): silicon, 0 and 500; iron, 35 and 187; acid-base, ammonium chloride as 0.5% of total diet (acidic), sodium bicarbonate as 1.0% of total diet (basic), or no supplementation of acid or base (control). The supplementation of 500 mg silicon/kg of diet increased plasma-iron concentration in rats fed the acidic or control diets, but not in rats fed the basic diet. A high dietary-iron level suppressed copper absorption and utilization and subsequently imposed a negative effect on its own utilization. An increase in the plasma total-cholesterol concentration caused by high dietary-iron level was likely a consequence of the antagonistic effect of iron on copper absorption and utilization. The use of cupric sulfate pentahydrate as the dietary-copper source in this study resulted in plasma copper concentrations that were approximately twice those obtained in a related study using cupric carbonate. Also, a 42% coefficient of variation (C.V.) for plasma-copper concentrations of rats fed cupric sulfate in this study was greatly reduced from the C.V. = 108% previously associated with the dietary cupric carbonate.