Excessive zinc in diet induces leptin resistance in Wistar rat through increased uptake of nutrients at intestinal level

ProjectThe ob gene has either been found to be mutant defective resulting in a deficiency of its product leptin or leptin has been found to be resistant to its receptors in obese human and rodents. The factors inducing leptin resistance have not been identified. Since excessive bioavailability of Zn has been implicated in obesity, we investigated if its excess in diet induces leptin resistance.ProcedureFor the investigations, three groups of Wistar rats were included in this study and they were fed on equicalories semi synthetic basal diet containing 20 mg, 40 mg or 80 mg Zn/kg diet for 120 days. There after they were sacrificed for hormonal status and intestinal investigations.ResultsThe data of this study revealed that the food intake, gain in body weight, serum leptin, glucose, insulin, cortisol increased with increased Zn concentration in diet. TEM study showed a positive correlation between Zn concentration in diet and number of microvilli/unit surface area of the mucosal epithelial cells of the intestine.ConclusionThe results of this study suggest that excessive bioavailability of Zn induces leptin resistance through increased uptake of nutrients at intestinal level, leading to the growth of the fat cells which aggravated the leptin synthesis and its release in the blood stream. In spite of its higher circulating level, it was unable to reduce the food intake and gain in body weight in Zn treated rats equivalent to the control group.     

Effects of zinc deficiency and zinc supplementation on homocysteine levels and related enzyme expression in rats

Methionine synthase (MS) and betaine-homocysteine methyltransferase (BHMT) are both zinc (Zn)-dependent methyltransferases and involved in the methylation of homocysteine. The objective of this study was to investigate the effects of dietary Zn supply on homocysteine levels and expression of the two enzymes in growing rats. Male weanling Sprague-Dawley rats were assigned randomly to four dietary groups (n = 8/group) for 3 weeks: Zn deficient (ZD; <1 mg Zn/kg); Zn control (ZC; 30 mg Zn/kg); Zn supplemented (ZS; 300 mg Zn/kg); pair fed (PF; 30 mg Zn/kg) to the ZD group. Serum and femur Zn concentrations were 83% and 58% lower in ZD, and 49% and 62% higher in ZS compared to ZC (P < 0.001), respectively. The ZD rats had lower feed intake (37%), body weight gains (45%), liver (43%) and kidney (31%) weights than those of ZC (P < 0.001), but these parameters in ZD were not significantly different from the PF controls. Serum homocysteine concentrations were 65% higher in ZD compared to PF (P < 0.05), and there was no significant difference in serum folate levels between ZD and PF groups. The mRNA expression of liver and kidney MS was 57% and 38% lower in ZD than PF (P < 0.001), respectively. Hepatic and renal BHMT mRNA levels were not altered in ZD compared to controls. The aforementioned measurements were not significantly different between ZS and ZC groups, except Zn levels. These results demonstrated that homocysteine homeostasis appeared to be disturbed by Zn deficiency but not Zn supplementation, and elevated serum homocysteine might be due to reduced expression of MS during Zn deficiency.     

Relative bioavailabilities of organic zinc sources with different chelation strengths for broilers fed diets with low or high phytate content

A six-day experiment was conducted to estimate the relative bioavailability values (RBV) of zinc (Zn) in three organic sources (oZn) with different chelation strengths compared to inorganic ZnSO₄ (iZn) for broilers fed a low or high phytate diet. A total of 1080, one-d-old male broiler chicks were randomly assigned to one of 18 dietary treatments (six replicates cages of ten chicks per cage) in a completely randomized design involving a 2 × 2 × 4 factorial arrangement with two levels of added phytate (0 or 10 g phytate as sodium phytate/kg), two levels of added Zn (30 or 60 mg/kg) and four Zn sources (iZn and three oZn sources) plus one low and one high phytate control treatments without Zn addition. The three oZn sources consisted of (1) Zn amino acid with weak chelation strength (ZnAA-L, formation quotient Q_f = 6.6, containing 119 g Zn/kg), (2) Zn proteinate with moderate chelation strength (ZnPRO-M, Q_f = 30.7, containing 133 g Zn/kg) or (3) Zn proteinate with strong chelation strength (ZnPRO-H, Q_f = 944.0, containing 186 g Zn/kg). Chicks were harvested at 6 days of age and pancreas metallothionein (MT) mRNA expression was used to estimate Zn RBV. Pancreas MT mRNA expression increased (P<0.01) as dietary Zn level increased. Chicks fed high phytate diets had lower (P<0.05) MT mRNA expression than chicks fed low phytate diets. Based on multiple linear regression slope ratios with ZnSO₄ set at 1.00, the RBV of ZnAA-L, ZnPRO-M and ZnPRO-H were 1.01, 1.28 and 0.70, respectively, for low phytate diets, and 1.05, 1.39 and 0.92, respectively, for high phytate diets. The slope for the oZn source with moderate chelation strength differed (P<0.05) from iZn and the other two oZn sources. The RBV of ZnAA-L, ZnPRO-M and ZnPRO-H under the high phytate diet increased by 0.04, 0.11 and 0.22, respectively, compared to those under the low phytate diet. Results indicate that the oZn sources with moderate or strong chelation strength offer partial or complete resistance to interference from high dietary phytate during digestion; and the oZn with moderate chelation strength had a greater RBV with both low and high phytate diets than iZn or oZn sources with weak or strong chelation strength.     

Calcium exacerbates the inhibitory effects of phytic acid on zinc bioavailability in rats

BackgroundComplementary feeding of breastfed infants with foods high in bioavailable zinc (Zn) can help meet physiological requirements for Zn. Some infant cereals contain high concentrations of phytic acid (PA) and calcium (Ca) that may reduce absorbable Zn.ObjectivesThis study measured PA, Zn and Ca concentrations in selected infant cereals sold in Canada and investigated the effects of dietary PA and Ca at concentrations present in infant cereals on Zn bioavailability in rats.Methods and resultsMale Sprague-Dawley rats (36-day old) were fed a control diet containing normal Zn (29.1 mg/kg) and Ca (4.95 g/kg) or six test diets (n = 12/diet group). Test diets were low in Zn (8.91–9.74 mg/kg) and contained low (2.16–2.17 g/kg), normal (5.00–5.11 g/kg) or high (14.6–14.9 g/kg) Ca without or with added PA (8 g/kg). After 2 weeks, rats were killed and Zn status of the rats was assessed. PA, Zn and Ca concentrations in infant cereals (n = 20) differed widely. PA concentrations ranged from undetectable to 16.0 g/kg. Zn and Ca concentrations ranged from 7.0–29.1 mg/kg and 0.8–13.4 g/kg, respectively. The [PA]/[Zn] and [PA × Ca]/[Zn] molar ratios in infants cereals with detectable PA (16 of 20 cereals) ranged from 22–75 and 0.9–14.9 mol/kg, respectively, predicting low Zn bioavailability. Body weight, body composition (lean and fat mass), right femur weight and length measurements and Zn concentrations in serum and femur indicated that diets higher in Ca had a more pronounced negative effect on Zn status of rats fed a PA-supplemented diet. Addition of PA to the diet had a greater negative effect on Zn status when Ca concentration in the diet was higher.ConclusionThese results show that, in rats, higher concentrations of dietary Ca and PA interact to potentiate a decrease in bioavailable Zn and may suggest lower Zn bioavailability in infant cereals with higher PA and Ca concentrations.     

Redistribution of tissue zinc pools during lactation and dyshomeostasis during marginal zinc deficiency in mice

Zinc (Zn) requirements are increased during lactation. Increased demand is partially met through increased Zn absorption from the diet. It is estimated that 60–80% of women of reproductive age are at risk for Zn deficiency due to low intake of bioavailable Zn and increased demands during pregnancy and lactation. How Zn is redistributed within the body to meet the demands of lactation, and how Zn deficiency affects this process, is not understood. Female C57bl/6J mice were fed a control (ZA; 30 mg Zn/kg) or a marginally Zn deficient (ZD; 15 mg Zn/kg) diet for 30 days prior to mating through mid-lactation and compared with nulliparous mice fed the same diets. While stomach and plasma Zn concentration increased during lactation in mice fed ZA, mice fed ZD had lower stomach Zn concentration and abrogated plasma Zn levels during lactation. Additionally, femur Zn decreased during lactation in mice fed ZA, while mice fed ZD did not experience this decrease. Furthermore, red blood cell, pancreas, muscle and mammary gland Zn concentration increased, and liver and adrenal gland Zn decreased during lactation, independent of diet, while kidney Zn concentration increased only in mice fed ZD. Finally, maternal Zn deficiency significantly increased the liver Zn concentration in offspring but decreased weight gain and survival. This study provides novel insight into how Zn is redistributed to meet the increased metabolic demands of lactation and how marginal Zn deficiency interferes with these homeostatic adjustments.     

The effect of zinc and phytoestrogen supplementation on the changes in mineral content of the femur of rats with chemically induced mammary carcinogenesis

The aim of this study was to assess skeletal effects of zinc or zinc with phytoestrogen (resveratrol or genistein) supplementation in an animal model of rats with DMBA-induced mammary carcinogenesis. The changes in bone parameters such as the length and mass were examined, as well as the changes in concentrations of selected minerals: calcium, magnesium, zinc, iron and phosphorus. Moreover, the investigations focused on finding the differences between the levels of iron and zinc in other tissues: the liver, spleen and serum of the examined rats.Fifty-six female Sprague–Dawley rats, 40 days old, were divided into four groups, regardless of the diets: standard (77 mg Zn kg/food), zinc (4.6 mg/mL via gavage), zinc (4.6 mg/mL) plus resveratrol (0.2 mg/kg bw), and zinc (4.6 mg/mL) plus genistein (0.2 mg/kg bw) for a period from 40 days until 20 weeks of age. The study rats were also treated with 7,12-dimethyl-1,2-benz[a]anthracene (DMBA) to induce mammary carcinogenesis.The applied diet and the advanced mammary cancer did not affect macrometric parameters of the rats’ bones, but they strongly affected their mineral content. It was found that mammary cancer, irrespectively of the applied diet, significantly modified the iron level in the femur, liver, spleen and serum of the examined rats. In addition, zinc supplementation significantly lowered the levels of calcium, magnesium and phosphorus in the femur of rats with mammary cancer as compared with respective levels in the control group. So, it was found that additional supplementation with zinc, which is generally considered to be an antioxidant, with the co-existing mammary carcinoma, increased the unfavorable changes as concerns the stability of bone tissue. The appropriate combination of zinc and phytoestrogens (resveratrol or genistein) could help prevent or slow bone loss associated with a range of skeletal disorders in breast cancer.     

l-Lysine supplementation does not affect the bioavailability of copper or iron in rats

l-lysine (Lys) is an essential amino acid that is added to foods and dietary supplements. Lys may interact with mineral nutrients and affect their metabolism. This study examined the effect of dietary Lys supplementation on the bioavailability of copper (Cu) and iron (Fe). Weanling male Sprague-Dawley rats were fed one of five diets (20% casein) for 4 weeks containing normal Cu and Fe (control) or low Cu or Fe without (LCu, LFe) or with (LCu + Lys, LFe + Lys) addition of 1.5% Lys. Final body weights, body weight gains and food consumption of the rats did not differ (P ≥ 0.05) among diet groups. Rats fed the low Cu or Fe diets showed changes in nutritional biomarkers compared to control rats, demonstrating reduced Cu and Fe status, respectively. Hematological parameters, serum ceruloplasmin activity and Cu and Fe concentrations in serum, liver, kidney and intestinal mucosa were unaffected (P ≥ 0.05) by Lys supplementation. These results indicate that in the context of an adequate protein diet, Lys supplementation at a relatively high level does not affect Cu or Fe bioavailability in rats.     

Interaction of dietary zinc and growth implants on weight gain,carcass traits and zinc in tissues of growing beef steers and heifers

In two separate studies, 60 beef heifers (379 kg BW) and 60 beef steers (348 kg BW) were randomly assigned to six treatments in 2×3 factorial arrangements. The treatments were with or without Synovex^® implants combined with either a control diet or diets supplemented with 200 ppm Zn from ZnSO₄ or zinc methionine (Zn-Met). Near the mid-point of the feeding periods, cattle were vaccinated with a modified live virus and subsequent titers and concentrations of immunoglobulin G (IgG) were measured. Liver and blood samples were obtained 1 week prior to the start of the experiments and at intervals during the experiments. In experiment 1, average daily gains of beef heifers were (P<0.05) affected by the interaction of implant and source of dietary Zn. Compared to control and ZnSO₄ treatments, supplementation with Zn-Met increased (P<0.05) the concentration of Zn in serum. Antibody titers and concentrations of IgG in serum were highest (P<0.05) in heifers fed ZnSO₄ compared to heifers fed the control or Zn-Met supplemented diets. The Synovex-H^® implant reduced the concentrations of Zn and Cu in liver. In experiment 2, Synovex-S^® implants improved (P<0.05) weight gains of steers supplemented with 200 ppm dietary Zn from ZnSO₄ compared to non-implanted steers. However, the implant had no effect when Zn-Met was the dietary Zn source. The implant increased (P<0.05) concentrations of Zn in liver of steers supplemented with 200 ppm dietary Zn and reduced Zn in liver of steers fed the control diet. Implanted steers had higher (P<0.05) Cu status and IgG concentrations in serum than non-implanted steers. Steers supplemented with either ZnSO₄ or Zn-Met had greater (P<0.05) concentrations of Zn in liver and plasma than steers fed the control diet. These results indicate both the level and source of Zn supplementation in diets of feedlot cattle affect their response to growth implants.     

The effects of dietary boric acid and borax supplementation on lipid peroxidation,antioxidant activity,and DNA damage in rats

The aims of this study were to clarify the effects of high dietary supplementation with boric acid and borax, called boron (B) compounds, on lipid peroxidation (LPO), antioxidant activity, some vitamin levels, and DNA damage in rats. Thirty Sprague Dawley male rats were divided into three equal groups: the animals in the first group (control) were fed with a standard rodent diet containing 6.4 mg B/kg, and the animals in the experimental group were fed with a standard rodent diet added with a supra-nutritional amount of boric acid and borax (100 mg B/kg) throughout the experimental period of 28 days. The B compounds decreased malondialdehyde (MDA), DNA damage, the protein carbonyl content (PCO) level in blood, and glutathione (GSH) concentration in the liver, Cu–Zn superoxide dismutase (SOD), and catalase (CAT) activity in the kidney. The B compounds increased GSH concentration in blood and the vitamin C level in plasma. Consequently, our results demonstrate that B supplementation (100 mg/kg) in diet decreases LPO, and enhances the antioxidant defense mechanism and vitamin status. There are no differences in oxidant/antioxidant balance and biochemical parameters except for serum vitamin A and liver GSH concentration, between the boron compounds used in this study.     

The effect of iron and zinc supplementation and discontinuation of this practice on iron and zinc level in tissues in rats fed deficient diets

The effect of iron and iron/zinc supplementation on their levels in tissues of rats fed initially one of the three following regimen: C – control AIN-93 diet, D – iron deficient diet and R – diet with 50% reduction of all vitamins and minerals was investigated. The study was conducted on 6-week male Wistar rats, in 3 stages: (1) 4-week adaptation to the diets (C, D or R); (2) 4-week supplementation with the same regimen enriched with 10-times more iron (CSFe, DSFe, RSFe) or iron/zinc (CSFeZn, DSFeZn, RSFeZn); (3) 2-week post-supplementation period (the same diets as the stage I). Iron and zinc content in serum, the initial segment of intestine, liver and kidney were measured using FAAS method. After supplementation period (stage II) the content of iron in the intestine, liver and kidney in groups of rats fed DSFe and DSFeZn-diet were significantly higher (all p-values ≤ 0.05) than in rats fed D-diet (intestine: DSFe = 50.1 ± 9.0 μg/g wet weight, DSFeZn = 43.0 ± 9.9 μg/g vs. D = 16.5 ± 2.1 μg/g; liver: DSFe = 149 ± 30 μg/g, DSFeZn = 152 ± 25 μg/g vs. D = 56 ± 13 μg/g; kidney: DSFe = 74.0 ± 8.1 μg/g, DSFeZn = 72.7 ± 6.6 μg/g vs. D = 59.3 ± 9.5 μg/g). The same significant associations (all p-values ≤ 0.05) were observed in R rats in the intestine and liver (intestine: RSFe = 60.8 ± 6.6 μg/g, RSFeZn = 54.8 ± 6.6 μg/g vs. R = 31.5 ± 8.2 μg/g; liver: RSFe = 161 ± 10 μg/g, RSFeZn = 166 ± 21 μg/g vs. R = 136 ± 24 μg/g). After post-supplementation period the statistically significant differences between supplemented and non-supplemented rats fed D- and R-diets were still observed. There was not found the effect of applied treatments on zinc status. In conclusion, iron or iron/zinc supplementation increased similarly iron level in tissues of rats fed D-diet or R-diet with prolonged effect after supplementation discontinuation.     

Accumulation of copper in the kidney of pigs fed high dietary zinc is due to metallothionein expression with minor effects on genes involved in copper metabolism

A study was conducted to determine the effect of high dietary zinc (Zn) oxide on trace element accumulation in various organs with special emphasis on the kidney. A total of 40 weaned piglets were allocated into two groups with 16 and 24 piglets each receiving a diet containing normal (NZn; 100 mg Zn/kg) or high (HZn; 2,100 mg Zn/kg) Zn concentration, respectively. After two weeks, eight piglets from each treatment were killed and organ samples were taken. Eight piglets from the remaining 16 pigs fed HZn diets were changed to NZn diets (CZn). All remaining piglets were killed after another two weeks for organ sampling. Trace element concentration was determined in the jejunum, liver, kidney, pancreas, bone (metacarpal IV), spleen, lung, thymus, tonsils and lymph nodes of jejunum, ileum and colon. Kidney mRNA expression of Zn transporter ZnT1 and ZIP4, genes involved in Cu metabolism (Ctr1, Atox1, SOD1, ATP7A, CCS, CP) and divalent metal ion transport (DMT1) and binding (MT-1a, MT-2b, MT-3) were determined. The Zn concentration in jejunum, liver, pancreas tissue and metacarpal IV was higher (P < 0.05) in HZn group compared with NZn and CZn groups. Trace element concentration in organs of CZn pigs was similar to those fed NZn diets. Zn concentration in muscle, lung and lymphatic organs as thymus, tonsils, spleen and lymph nodes of jejunum, ileum and colon did not differ between the groups. Zn and Cu were positively correlated (R = 0.67; P < 0.05) in the kidney. No significant differences for Cu chaperones, Cu transporters and Cu-dependent factors were determined despite decreased expression of Atox1 after two weeks and increased Ctr1 expression over time in the HZn group. Expression of MT-1a, MT-2b and MT-3 were significantly higher in HZn fed pigs with most pronounced effects for MT-1a > MT-2b > MT-3. Gene expression of MTs in pigs fed CZn diets did not differ from pigs fed NZn diets. The data suggest that high dietary Zn feeding in pigs leads to Cu co-accumulation in the kidney of pigs with minor effect on genes relevant for Cu metabolism. In addition, the organ Zn and Cu accumulation is reversible after two weeks of withdrawal of high dietary Zn.     

The relationship between the rate of chelator-induced zinc efflux from erythrocytes and zinc status

The rate of zinc (Zn) release from rat erythrocytes incubated in buffers containing a variety of chelators was measured. Only o-phenanthroline, 8-hydroxyquinoline-5-sulfonate, and EDTA caused detectable Zn release. The relationship between the rate of this release in the presence of o-phenanthroline and Zn status was determined in rats. Rats were fed one of the following: a modified AIN-76 diet providing 46 mumol (3 mg) Zn per kg of diet, a pair-fed diet providing 459 mumol (30 mg)/kg, or the previous diet fed ad lib. Animals were sacrificed at 2-wk intervals for 12 wk, and the Zn efflux rate, plasma, liver, and femur Zn concentrations were determined. The efflux rate was lower in erythrocytes taken from the rats fed the low-Zn diet. The efflux rate was also well correlated with femur Zn (r = 0.509, n = 98, p < 0.0001). A poorer correlation was observed with plasma Zn in the rats. Correlations also were determined between efflux rates and plasma Zn levels in human subjects. There was a significant correlation only in the males. In was concluded that the Zn efflux rate from erythrocytes incubated in the presence of o-phenanthroline is related to Zn status but is not sensitive enough to be a useful index of this status.     

Effects of zinc pre-treatment on blood glutathione,serum zinc and kidney histological organisation in male rats exposed to cadmium

The effects of sub-chronic exposure to cadmium (Cd) on the blood glutathione, serum zinc and on the kidney histological organisation in rats as well as the possible protective role of zinc (Zn) are the object of this study. For this purpose, 60 male Wistar rats (8 weeks old) were divided into three groups: the first group was exposed to Cd in the form of CdCl₂, administered in five doses (each of 0.4 mg Cd/kg b.w.) on days 5, 10, 15, 20 and 25, giving a total dose of 2 mg Cd/kg b.w., i.p.; the second group was simultaneously exposed to Zn and Cd with the same timeline and the same doses of Cd as the first group but with, in addition, injections of Zn in the form of ZnCl₂, administered in doses of 0.8 mg Zn/kg b.w., giving a total dose of 4 mg Zn/kg b w, i.p.; a control group received 0.5 mL of physiological saline in an identical manner. Intoxication with Cd was followed by a significant decrease in blood glutathione, increase in oxidized glutathione as well as histological damage in kidneys. Pre-treatment with Zn exhibited a protective role against Cd toxicity with a significant decrease in serum zinc content. This fact may be explained by an excessive use of zinc in metallothionein synthesis as a cadmium detoxification agent.     

The bioavailability of different zinc compounds used as human dietary supplements in rat prostate: a comparative study

The normal human prostate accumulates the highest levels of zinc (Zn) of any soft tissue in the body. The pool of zinc available to the body is known to significantly decrease with age. It is suggested that dietary Zn supplementation protects against oxidative damage and reduces the risk of cancer. Zinc sulfate and zinc gluconate were the most frequently mentioned in per os administration in studies on Zn supplementation. The major aim of the study was to compare the bioavailability of different Zn compounds (sulfate, gluconate and citrate) in the prostate after their daily administration to male rats at three different doses (3.0; 15.0; and 50.0 mg Zn/kg b.w.) for 30 days. The results show that bioavailability in the prostate differs significantly between individual zinc preparations. A significantly elevated Zn concentration in the dorso-lateral lobe of the prostate, compared to controls, was found in the rats supplemented with two compounds only: zinc gluconate and zinc citrate. However, after administration of zinc gluconate, this effect occurred even at the lowest dose. The lowest zinc bioavailability in the prostate was found in the rats administered zinc sulfate: no significant Zn increase was seen in particular zones of the prostate. To sum up, the use of zinc gluconate is worth considering as a possible means of zinc supplementation in men.     

Protective effect of combined therapy with dithiothreitol,zinc and selenium protects acute mercury induced oxidative injury in rats

The present study was undertaken to establish mode of action, comparative therapeutic efficacy and safety evaluation of dithiothreitol (DTT) supplemented with Zn and Se against dimethylmercury in rats. Adult male albino rats of Sprague-Dawley strain (150 ± 10 g, n = 6 per group) were exposed a bolus dose of dimethylmercury (10 mg/kg, p.o.) for once only followed by DTT (15.4 mg/kg, i.p.) along with the combination of antioxidants Zn and Se (2 mmol/kg and 0.5 mg/kg, p.o.) after 72 h of toxicant administration for three days. The results showed a significant (P ≤ 0.05) increase in the activities of AST, ALT, alkaline phosphatase, lactate dehydrogenase, in serum after toxicant administration. This was accompanied by histopathological observations. A significant rise was observed in lipid peroxidation level and mercury ion concentration however reduced glutathione content decreased in liver, kidney and brain. A significant (P ≤ 0.05) decrease in the activity of acetyl cholinesterase was also seen in different regions of brain. Combined treatment of DTT along with Zn and Se significantly (P ≤ 0.05) recouped the alterations in the enzymatic activities of serum and reversed the tissue biochemical and histopathological changes of liver, kidney and brain. Our results demonstrate that combined treatment of thiol chelator (DTT) along with antioxidants (Zn and Se) plays an important role against dimethylmercury induced tissue damage and hepatic, nephro and neurotoxicity.     

Magnification of the therapeutic uses of pomegranate fruits and peel in rats injected with carbon tetrachloride (Ccl4)

The liver is more prone to infections that cause fibrosis, such as steatosis, non-alcoholic steatohepatitis, hepatotoxicity, cirrhosis, and hepatocellular carcinoma. Also, Viral hepatitis is a common condition worldwide it worsens into chronic inflammation of the liver. One of the healthiest fruits is the pomegranate for the body and health, as it contains a high nutritional value of minerals, vitamins, antioxidants, so we worked on this investigation to magnify the therapeutic applications of pomegranate fruits (POF) and peel (POP) in carbon tetrachloride-injected rats (Ccl4). The experiment was carried out in a caged animal. All rats were fed a basal diet for one week before the study, and they were divided into seven groups, each with six rats. As a control negative group (C–ve), the first group sample was fed only the basal diet for 28 days. The remaining rats (n = 36) were injected with carbon tetrachloride (Ccl4). Five groups were fed varying concentrations of (5 %, 10 %, 15 % POF, 5 %, and 10 % pomegranate peel (POP)), whereas one group was diagnosed with the illness and disease, and didn't even feed the experimental diet. The results revealed significant increases in T.BIL, D.BIL, and BIL in the serum of rats injected by CC14 to induce hepatopathy compared to the healthy group (normal rats). Also, the best treatment considering the serum D.BIL was recorded for the 5 % POF.     

Effects of diets of differing fiber contents on digestibility,passage rate of digesta and heat production in lesser mouse deer (Tragulus javanicus)

The effects of different levels of dietary fiber on feed intake, digestibility, mean retention times of solute and particle and heat production were studied in twelve male lesser mouse deer (Tragulus javanicus). The animals were randomly assigned into four groups of three mouse deer each and fed on individual basis. Four diets, namely A, B, C and D were prepared in pellet forms. Each diet contained ～14% crude protein and ～18 kJ/g gross energy. The crude fiber contents of diet A, B, C and D were 4.2, 11.3, 16.8 and 22.5%, respectively. The results showed that the crude fiber intake of mouse deer was 1.4 ± 0.04, 3.8 ± 0.4, 5.8 ± 0.7 and 6.0 ± 0.6 g/kg W^0.75/d fed diet A, B, C and D, respectively. Mouse deer fed diet D had significantly lower DM intake than those fed lower levels of fiber. The digestibility values of DM decreased gradually with increasing levels of fiber in the diet. The mean retention times (MRTs) of particles (～1.5 mm) in the reticulorumen were in the range of (19.0–22.9 h), with the shortest time for mouse deer fed diet D. However mouse deer fed diet C and D showed significant shorter solute MRT in the reticulorumen (17.1–18.5 h) when compared to mouse deer fed lower fiber diets (21.4–21.9 h). The selectivity factor in the reticulorumen was in the range of 1.04–1.18, indicating the mouse deer to be a ‘moose-type’ ruminant. Fiber levels had no significant effect on water intake of mouse deer. Heat production tended to decrease with increasing levels of fiber (448.3–435.7 kJ/kg W^0.75/d) but differences among the mouse deer fed the four diets were not significant.     

Lead,zinc, cadmium hyperaccumulation and growth stimulation in Arabis paniculata Franch

Metal hyperaccumulation is of great interest in recent years because of its potential application for phytoremediation of heavy metal contaminated soils. In this study, a field survey and a hydroponic experiment were conducted to study the accumulation characteristics of lead (Pb), zinc (Zn) and cadmium (Cd) in Arabis paniculata Franch., which was found in Yunnan Province, China. The field survey showed that the wild population of A. paniculata was hyper-tolerant to extremely high concentrations of Pb, Zn and Cd, and could accumulate in shoots an average level of 2300 mg kg^?1 dry weight (DW) Pb, 20,800 mg kg^?1 Zn and 434 mg kg^?1 Cd, with their translocation factors (TFs) all above one. Under the hydroponic culture, stimulatory effects of Pb, Zn and Cd on shoot dry biomass were noted from 24 to 193 μM Pb, 9 to 178 μM Cd and all Zn supply levels in nutrient solution, while the effects were not obvious in the roots. Chlorophyll concentrations in Pb, Zn and Cd treatments showed an inverted U-shaped pattern, consistent with the change of plant biomass. Pb, Zn and Cd concentrations in the shoots and roots increased sharply with increasing Pb, Zn and Cd supply levels. They reached > 1000 mg kg^?1 Pb, 10,000 mg kg^?1 Zn and 100 mg kg^?1 Cd DW in the 24 μM Pb, 1223 μM Zn and 9 μM Cd treatment, respectively, in which the plants grew healthy and did not show any symptoms of phytotoxicity. The TFs of Zn were basically higher than one and the amount of Zn taken by shoots ranged from 78.7 to 90.4% of the total Zn. However, the TFs of Pb and Cd were well below one, and 55.0–67.5% of total Pb and 57.8–83.5% of total Cd was accumulated in the shoots. These results indicate that A. paniculata has a strong ability to tolerate and hyperaccumulate Pb, Zn and Cd. Meanwhile, suitable levels of Pb, Zn and Cd could stimulate the biomass production and chlorophyll concentrations of A. paniculata. Thus, it provides a new plant material for understanding the mechanisms of stimulatory effect and co-hyperaccumulation of multiple heavy metals.     

Tolerance,accumulation and distribution of zinc and cadmium in hyperaccumulator Potentilla griffithii

In this study, zinc (Zn) and cadmium (Cd) tolerance, accumulation and distribution was conducted in Potentilla griffithii H., which has been identified as a new Zn hyperaccumulator found in China. Plants were grown hydroponically with different levels of Zn²⁺ (20, 40, 80 and 160 mg L^?1) and Cd²⁺ (5, 10, 20 and 40 mg L^?1) for 60 days. All plants grew healthy and attained more biomass than the control, except 40 mg L^?1 Cd treatment. Zn or Cd concentration in plants increased steadily with the increasing addition of Zn or Cd in solution. The maximum metal concentrations in roots, petioles and leaves were 14,060, 19,600 and 11,400 mg kg^?1 Zn dry weight (DW) at 160 mg L^?1 Zn treatment, and 9098, 3077 and 852 mg kg^?1 Cd DW at 40 mg L^?1 Cd treatment, respectively. These results suggest that P. griffithii has a high ability to tolerate and accumulate Cd and Zn, and it can be considered not only as Zn but also as a potential cadmium hyperaccumulator. Light microscope (LM) with histochemical method, scanning electron microscope combined with energy dispersive spectrometry (SEM-EDS) and transmission electron microscope (TEM) were used to determine the distribution of Zn and Cd in P. griffithii at tissue and cellular levels. In roots, SEM-EDS confirmed that the highest Zn concentration was found in xylem parenchyma cells and epidermal cells, while for Cd, a gradient was observed with the highest Cd concentration in rhizodermal and cortex cells, followed by central cylinder. LM results showed that Zn and Cd distributed mainly along the walls of epidermis, cortex, endodermis and some xylem parenchyma. In leaves, Zn and Cd shared the similar distribution pattern, and both were mostly accumulated in epidermis and bundle sheath. However, in leaves of 40 mg L^?1 Cd treatment, which caused the phytotoxicity, Cd was also found in the mesophyll cells. The major storage site for Zn and Cd in leaves of P. griffithii was vacuoles, to a lesser extent cell wall or cytosol. The present study demonstrates that the predominant sequestration of Zn and Cd in cell walls of roots and in vacuoles of epidermis and bundle sheath of leaves may play a major role in strong tolerance and hyperaccumulation of Zn and Cd in P. griffithii.