Home About us Contact
|
Home About us Contact | ||
|
|
||
Zn Levels (zn + level)
Selected AbstractsEffects of dietary zinc levels on growth, serum zinc, haematological parameters and tissue trace elements of soft-shelled turtles, Pelodiscus sinensisAQUACULTURE NUTRITION, Issue 3 2010S.-C. HUANG Abstract A 10-week feeding trial was conducted to evaluate the effects of dietary zinc (Zn) contents on the growth, tissue trace element contents and serum Zn levels in soft-shelled turtles, Pelodiscus sinensis. Juvenile soft-shelled turtles approximately 4.8 g in body weight were fed casein-based diets containing seven levels of Zn (14, 23, 32, 43, 58, 87 and 100 mg kg,1) for 10 weeks. There were no significant differences (P > 0.05) in weight gain (WG), feed conversion ratio (FCR) or protein efficiency ratio (PER) among the dietary treatments. However, Zn concentrations in the liver, serum and carapace of turtles fed the basal diet containing 14 mg Zn kg,1 were the lowest among all groups. Zn contents in the liver, serum and carapace increased when dietary Zn increased up to a dietary Zn level of approximately 43 mg kg,1. Beyond this dietary level, tissue Zn contents were relatively constant. Carapace iron (Fe), selenium (Se) in hard tissues and haemoglobin concentrations decreased when dietary Zn increased. Dietary Zn requirements of juvenile soft-shelled turtles derived from regression modelling using the liver, serum, carapace and bone Zn contents as indicators were 42, 39, 35 and 46 mg Zn kg,1, respectively. [source] Induction of morphological deformities in Chironomus tentans exposed to zinc- and lead-spiked sedimentsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2001Edward A. Martinez Abstract Laboratory experiments were used to assess morphological responses of Chironomus tentans larvae exposed to three levels of zinc and lead. Chironomus tentans egg masses were placed into triplicate control and metal-spiked aquaria containing the measured concentrations 1,442, 3,383, and 5,562 ,g/g Pb dry weight and 1,723, 3,743, and 5,252 ,g/g Zn dry weight. Larvae were collected at 10-d intervals after egg masses were placed in aquaria until final emergence. Larvae were screened formouthpart deformities and metal body burdens. Deformities increased with time of exposure in both Zn and Pb tanks. Deformity rates between the three Zn concentrations differed statistically, with low and medium Zn levels containing the highest overall deformity rates of 12%. Deformity rates for larvae held in the Pb aquaria were found to differ significantly. Larvae in the low-Pb tanks had a deformity rate of 9%. Larvae and water from both the Zn and Pb aquaria had increasing metal concentrations with increasing sediment metal concentration. Results demonstrate that Zn and Pb each induce chironomid mouthpart deformities at various concentrations. However, a clear dose-related response was not demonstrated. Our research provides more support for the potential use of chironomid deformities as a tool for the assessment of heavy metal pollution in aquatic systems. [source] Efficacy of the injectable calcium phosphate ceramics suspensions containing magnesium, zinc and fluoride on the bone mineral deficiency in ovariectomized ratsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2008Makoto Otsuka Abstract The purpose of this study was to evaluate the therapeutic efficacy of a new calcium phosphate (CaP)-based formulation in improving the bone mineral deficiency in ovariectomized (OVX) rats. The ions release experiments for CaP preparations (G2: 0.46% Mg, 5.78% Zn, and 2.5% F; G3:3.1% Mg, 0.03% Zn, and 3.01% F; G4: 1.25% Mg, 1.77% Zn, 1.35% F) and of a Zn-TCP (G1: 6.17% Zn) powders, the initial Mg and Zn ion release rates of MZF-CaPs were performed in acetate buffer at pH 4.5 (37°C). Wistar rats were divided into six groups including a normal (not OVX) group (GN) and a control, OVX group (GC). Rats in groups GC, G1, G2, G3, G4 were OVX. Suspensions consisting of CaP preparations (G2, G3, G4) and of a Zn-TCP (G1) powders were injected in the right thighs of OVX rats in all groups except for GN and GC, once a week for 4 weeks. GN and GC rats were injected with saline solutions. Plasma was analyzed for Zn land alkaline phosphatase levels. The bone mineral density (BMD) was measured using DEXA and the bone (femur) strength determined using three-point-bending analysis. G1 and G2 groups showed high plasma Zn levels. The area under the curve of plasma Zn was significantly greater in the G1, G2, and GN groups than in the G3, G4, and GC groups (p,<,0.05). The BMD and bone mechanical strength of the right femur were significantly higher in the G1, G2, G3, and G4 groups than GC group on day 28. The right femur had significantly greater BMD and bone mechanical strength than the left femur in G1, G2, G3, and G4 groups. However, there was no significant difference in the BMD of the right femur between the G1, G2, G3, and G4 groups. Results indicate that the new injectable CaP formulations are effective in improving bone properties of OVX rats and may be useful in osteoporosis therapy. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:421,432, 2008 [source] Essential elements and contaminants in tissues of commercial pelagic fish from the Eastern Mediterranean SeaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2009Beyza Ersoy Abstract BACKGROUND: It is important to determine the concentrations of essential and non-essential metals in fish for human health. The essential elements and contaminants (Pb and Cd) were determined seasonally in the muscle and liver of some pelagic fish species round herring (Etrumeus teres), chub mackerel (Scomber japonicus), golden grey mullet (Liza aurata) and Mediterranean horse mackerel (Trachurus mediterraneus) from the Iskenderun Bay, Eastern Mediterranean Sea. RESULTS: The Na, K, Ca and Mg were the most abundant elements in muscle and liver tissues. The Na, K, Ca and Mg concentrations in fish tissues were between 51.7 and 3426 mg kg,1. Muscle accumulated the lowest levels of elements. Trace element and contaminant levels in muscle were highest in spring and summer. The Cu, Zn and Cr concentrations were highest in summer. The Ni, Mn and Fe concentrations were highest in spring. The maximum Pb concentrations in the muscle and liver of fish species was 0.39 and 0.80 mg kg,1 in autumn. The maximum Cd concentration in the muscle of fish was 0.27 mg kg,1 in spring and the maximum Cd concentration in the liver was 0.78 mg kg,1 in summer. CONCLUSION: The Cr, Pb, Cd, Cu and Zn levels in muscle were found to be lower than permissible limits reported by various authorities. Estimated weekly and daily intake for Pb and Cd by consumption of fish muscle were far below the PTWI and PTDI values established by FAO/WHO. Copyright © 2009 Society of Chemical Industry [source] Effects of Fungal Phytase on Utilization of Dietary Protein and Minerals, and Dephosphorylation of Phytic Acid in the Alimentary Tract of Channel Catfish Ictalurus punctatus Fed an All-Plant-Protein DietJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2002Weibing Yan A feeding trial was conducted to quantify the effects of phytase at levels of 0, 500, 1,000, 2,000, 4,000, and 8,000 units (U) per kg diet on utilization of dietary protein and minerals by fingerling (12 g) channel catfish Ictalurus punctatus fed an all-plant-protein diet composed of soybean meal, corn, and wheat middlings. The effects of phytase on dephosphorylation of phytic acid (phytate) in the alimentary tract of catfish also were determined. After 14 wk, mean weight gains (30.2,43.9 g/fish), feed conversion ratios (2.27,2.40 g feed consumed/g weight gain), protein efficiency ratios (1.47,1.61 g weight gaid/g protein consumed), and dietary protein retentions (23.8,26.7%) did not differ significantly (P > 0.05) among treatment groups. A digestibility trial conducted after the feeding trial showed no difference (P > 0.05) in mean digestibility of diet dry matter (49.0,58.3%) or crude protein (85.4-88.5%) among treatment groups. Concentrations of ash (46.7,48.6%), calcium (Ca, 17.9,18.5%), phosphorus (P, 9.1,9.5%), and manganese (Mn, 65.5,74.1 mg/kg) were significantly higher (P , 0.05) in bone of fish fed , 500 U/kg than in bone of fish fed 0 U/kg (ash, 43.5%; Ca, 16.4%; P, 8.4%; and Mn, 49.0 ma/kg), but concentrations of these minerals did not differ (P > 0.05) in bone of fish fed , 500 Uk/g. The magnesium (Mg) content of bone did not differ (P > 0.05) between fish fed 0 U/kg (0.29%) or 500 U/kg (0.34%), but was significantly lower in fish fed 0 U/kg than in fish fed , 1,000 U/kg (0.35,37%). Bone Mg levels did not differ (P > 0.05) among fish fed , 500 U/kg. The amount of zinc (Zn) in bone of fish fed 8,000 U/kg (153.3 mg/kg) was significantly higher than that in fish fed 0 U/kg (115.7 mg/kg) or 500 U/kg (130.3 mg/ kg), but did not differ from Zn levels in bone of fish fed 1,000,4,000 U/kg (134.5,135.8 mg/ kg). Dephosphorylation of phytate occurred primarily in the stomach within 2,8 h after diet ingestion, depending on the level of phytase supplementation. Initial levels of total phytate in the diet decreased 32,94% in stomach contents of fish fed l,000,8,000 U/kg within 2 h after feeding. Eight hours after feeding, stomach contents of fish fed , 1,000 U/kg contained less than 6% of initial total dietary phytate. Stomach contents of fish fed 500 U/kg retained 92% of initial total dietary phytate 2 h after feeding and 15% of total dietary phytate 8 h after feeding. Results of this study indicate that phytase supplementation at levels up to 8,000 U/kg diet did not increase weight gain or improve dietary protein utilization of channel catfish fed an all-plant-protein diet. Addition of phytase at a level of 1,000 U/kg diet was sufficient to significantly increase the Ca, P, Mg, and Mn content of bone, relative to fish fed an unsupplemented diet, and significantly decrease the quantity of total phytate in feces. A phytase level of 8,000 U/kg diet significantly increased the bioavailability of naturally occurring Zn in feed ingredients and increased the rate of phytate dephosphorylation in the stomach, compared with a diet containing no added phytase. Increased utilization of naturally occurring minerals in feed ingredients reduces the need for mineral supplements in diets and results in decreased elimination of minerals in feces. Thus, use of phytase in catfish feeds can be expected to provide both economic and environmental benefits. [source] Cadmium partitioning and gene expression studies in Nicotiana tabacum and Nicotiana rusticaPHYSIOLOGIA PLANTARUM, Issue 3 2006Lucien Bovet To better understand the differences in cadmium (Cd) uptake, partitioning and gene regulation between Nicotiana tabacum and Nicotiana rustica, we compared these two species for root and leaf Cd concentrations after different Cd exposures, 109Cd root-to-shoot transport, Cd tolerance as well as differential gene expression in roots exposed or not to CdCl2 using reverse transcriptase,PCR (RT-PCR). When grown in 1 ,M CdCl2 for 7 days, N. rustica exhibited higher root and lower leaf Cd contents than N. tabacum. Data were confirmed by radiolabeling experiments, which further showed that some 109Cd accumulated in the distal part of lateral roots in N. rustica. Visual inspection of leaves suggested that N. rustica was somewhat more tolerant to high Cd exposure (50 ,M CdCl2) compared with N. tabacum. At such a high Cd concentration, Cd toxic effects on N. tabacum leaves were apparently not directly related to the homeostasis of Fe and Mn. However, the Zn levels were different in N. rustica compared with N. tabacum in absence and presence of Cd treatments. Root growth experiments revealed that N. tabacum, but not N. rustica, root length was reduced in bactoagar medium containing 20 ,M CdCl2. Complementary DNA microarrays were used as a screening approach to demonstrate by RT-PCR that some gene products were differentially regulated by Cd in N. rustica and in N. tabacum. In addition, "NtIRT1,"NtMTP1a, "NtHMA3" and "NtNAS3" were inducible by Cd in N. tabacum. Interestingly "NtIRT1" and NtMTP1a were differently expressed between the two species. Our results suggest different pathways for Cd sequestration and transport between these two species. [source] Effects of dietary zinc levels on growth, serum zinc, haematological parameters and tissue trace elements of soft-shelled turtles, Pelodiscus sinensisAQUACULTURE NUTRITION, Issue 3 2010S.-C. HUANG Abstract A 10-week feeding trial was conducted to evaluate the effects of dietary zinc (Zn) contents on the growth, tissue trace element contents and serum Zn levels in soft-shelled turtles, Pelodiscus sinensis. Juvenile soft-shelled turtles approximately 4.8 g in body weight were fed casein-based diets containing seven levels of Zn (14, 23, 32, 43, 58, 87 and 100 mg kg,1) for 10 weeks. There were no significant differences (P > 0.05) in weight gain (WG), feed conversion ratio (FCR) or protein efficiency ratio (PER) among the dietary treatments. However, Zn concentrations in the liver, serum and carapace of turtles fed the basal diet containing 14 mg Zn kg,1 were the lowest among all groups. Zn contents in the liver, serum and carapace increased when dietary Zn increased up to a dietary Zn level of approximately 43 mg kg,1. Beyond this dietary level, tissue Zn contents were relatively constant. Carapace iron (Fe), selenium (Se) in hard tissues and haemoglobin concentrations decreased when dietary Zn increased. Dietary Zn requirements of juvenile soft-shelled turtles derived from regression modelling using the liver, serum, carapace and bone Zn contents as indicators were 42, 39, 35 and 46 mg Zn kg,1, respectively. [source] Trace Metals' Abnormalities in Hemodialysis Patients: Relationship with MedicationsARTIFICIAL ORGANS, Issue 11 2000Su-Hui Lee Abstract: A multicenter collaborative study was performed to investigate the prevalence of abnormal blood contents of 6 trace metals, copper (Cu), zinc (Zn), aluminum (Al), lead (Pb), cadmium (Cd), and mercury (Hg), in hemodialysis (HD) patients and to analyze their relationship with the medications, such as CaCO3, Ca acetate, Al containing phosphate-binding agents, 1,25-dihydroxy vitD3, 1-hydroxy vitD3, and erythropoietin (EPO), as well as hematocrit level, by chi-square statistics. From 6 medical centers in Taiwan, we included 456 patients in maintenance HD for more than 4 months for this study, and they had continued the previously mentioned medications for at least 3 months. Blood samples were collected before initiating HD, and atomic absorption spectrophotometry was used to measure plasma levels of Cu, Zn, and Al as well as whole blood levels of Pb, Cd, and Hg. Three hundred seventy-five (78%) of the HD patients had low plasma Zn levels, that is, <800 ,g/L, and the mean (±SD) concentration was 705.8 (±128.23) ,g/L in all subjects. One hundred forty-one (31%) of the HD patients had high plasma Al, that is, >50 ,g/L, and the mean (±SD) was 44.30 (±28.28) ,g/L in all subjects. Three hundred thirty-three (73%) of the dialysis patients had high Cd levels, that is, >2.5 ,g/L, and the mean (±SD) was 3.32 (±1.49) ,g/L in all subjects. The majority of HD patients had normal blood levels of Cu, PB, and Hg. Only 21 (4.6%), 5 (1.1%), and 3 (0.06%) patients had elevated blood levels of Cu, Pb, and Hg, respectively. Their mean (±SD) blood concentration of Cu, Pb, and Hg were 1,049.78 (±233.25) ,g/L, 7.45 (±3.95) ,g/dL, and 3.17 (±25.56) ,g/L, respectively. Three patients had elevated plasma Hg concentrations, that is, 546, 12.6, and 24.0 ,g/L, respectively. In the 152 normal healthy age and sex matched control group, the blood levels of Al, Cd, and Pb were all significantly lower than the HD patients. However, the levels of Cu and Zn were higher in the control group. The Hg level was not significantly different in both groups. There was no statistical difference between patients with normal and abnormal blood levels of trace metals in various medications except Al containing phosphate binder. The Al containing phosphate binder users had significantly higher plasma Al levels (54.71 ± 26.70 versus 41.15 ± 28.03 ,g/L, p < 0.001) and hematocrit levels (29.61 ± 4.61 versus 27.81 ± 3.91, p < 0.0005). There was no statistical correlation between erythropoietin (EPO) dose and hematocrit level in these patients. In conclusion, the blood level of trace metals of these HD patients except Al was not related to their medications. However, caution must be exercised in interpreting this result as dose and duration of medication; efficiency of HD and water treatment may play an important role. Otherwise, environmental factors, diet, and the aging process may contribute to the trace metal burden in uremia. Thus, Zn and Cu are abundant in seafood, and Cd is abundant in contaminated plants such as rice. [source] | ||||||||||||||||