The effects of cadmium in feed, and its amelioration with zinc, on element balances in sheep1

TRAF2/ASK1/JNK Signaling Pathway Is Involved in the Lung Apoptosis of Swine Induced by Cadmium Exposure

Cadmium (Cd), a toxic heavy metal, exists widely in the environment, which can enter organisms through a variety of ways and cause damage to various organs and tissues. However, the mechanism of lung toxicity in swine after Cd exposure is still unclear. To explore the molecular mechanism of swine lung damage caused by Cd exposure, we established the model of Cd exposure, and Cd chloride (20 mg/kg CdCl₂) was added to the diet of swine for continuous exposure for 40 days. TUNEL staining showed that the apoptosis of swine lung increased significantly after Cd exposure. Meanwhile, the results of qRT-PCR showed that Cd induced oxidative stress and inhibited the expression of antioxidant enzymes including CAT, GCLM, GST, SOD, and GSH-px in lung tissue. Cd exposure activated mitochondrial apoptosis pathway via the TRAF2/ASK1/JNK signaling pathway. In brief, we considered that Cd exposure causes oxidative stress in lung and induces lung cell apoptosis through the TRAF2/ASK1/JNK pathway and increases the expression of HSPs to resist the toxicity of Cd. Our research enriches the theoretical basis of Cd toxicity and provides reference for comparative medicine.

Can zinc supplementation ameliorate cadmium-induced alterations in the bioelement content in rabbits?

The study was designed to investigate the influence of zinc (Zn) supplementation on cadmium-induced alterations in zinc, copper (Cu), and magnesium (Mg) status in rabbits. For this purpose, the concentrations of cadmium (Cd), Zn, Cu, and Mg were estimated in the blood, liver, kidney, and bone. The rabbits were divided in a control group, a Cd group-animals intoxicated orally with Cd (10 mg kg-1 bw, as aqueous solution of Cd-chloride), and a Cd+Zn group-animals intoxicated with the same dose of Cd and co-treated with Zn (20 mg kg-1 bw, as aqueous solution of Zn-sulphate). Solutions were administered orally, every day for 28 days. Sample mineralisation was performed with concentrated nitric acid (HNO3) and perchloric acid (HClO4) (4:1) and metal concentrations were determined by atomic absorption spectrophotometry (AAS). Zinc supplementation improved some of Cd-induced disturbances in bioelement levels in the investigated tissues. Beneficial effects of Zn on Zn and Cu levels were observed in blood, as well as on the Cu kidney level. The calculated values for Cu/Zn, Mg/Zn, and Mg/Cu ratios in blood suggest that Zn co-treatment reduces Cd-induced changes in bioelement ratios in blood.

Effects of duration of salt supplementation of sheep on rumen metabolism and the accumulation of elements

Sheep may adapt rumen function in response to supplementary sodium, potentially affecting the metabolism and accumulation of this element and related elements in target tissues and organs. In this study, sheep were provided with a supplement of sodium added to silage for 3, 6 or 9 weeks. There was no evidence of adaptation of rumen function that would have benefited digestion or element absorption, on the contrary, after 6 and 9 weeks supplementation compared with 3 weeks, the buffering capacity of rumen solids was reduced and their density increased, with long particles that were associated with high dry matter contents. Potassium concentration in kidneys increased after 9 week of supplementation, in conjunction with reduced bone potassium concentration. In addition, the concentration of cadmium, an element known to compete with sodium, increased in rumen contents and its availability decreased. Copper was increased in the brain and eyes after 9 weeks of supplementation with NaCl, and after 6 weeks, copper in blood plasma decreased. It is concluded that there was evidence of a dynamic response to NaCl supplementation, which affected rumen solids and the accumulation of several important elements in key target organs.

Mineral deposition in tissues of cattle fed with different phosphates and relationships phosphorus: fluorine

Forty-nine male calves were allotted in a randomized design, initially seven replicates per treatment at the end of the experiment were slaughtered four animals per treatment. Treatments CONT: control diet; FBC120: Dicalcium Phosphate 120:1 ratio P: F; MBC60: Monodicalcium phosphate 60:1 ratio P:F; FBC30: Dicalcium Phosphate 30:1 ratio P:F; SFT30: Super triple phosphate 30:1 ratio P:F; FBC10: Dicalcium Phosphate 10:1 ratio P:F; CAR10: concentrated ratio of 10:1 rock Q:F. Phosphates less elaborate showed higher amounts of heavy metals. In bones, iron, aluminum and lead were higher in FBC10 diet, the copper content was higher in animals fed the diet MBC60. Magnesium in liver was higher in animals fed diet FBC30, aluminum was higher for treatments SFT30 and FBC10, FBC120 and the cadmium and lead levels were higher in animals that received STF30. Treatments did not affect phosphorus and fluorine in muscle and heart, being that chromium was higher in the muscle of animals fed diets CAR10 and STF30 while cadmium in heart was greater in diet CAR10. Kidney phosphorus was higher in the animals fed the diet CAR10 and lower dietary FBC10, while aluminum was higher in the animals fed with the diet FBC10 and lower dietary FBC120 and levels of chromium and lead were higher in animals CAR10 diet and lowest in diet MBC60. Alternative sources of phosphorus and low ratios P:F increased the deposition of minerals in bones and liver, and this mineral deposition was lower in the muscles.

Deposition of copper, iron, manganese and zinc in the empty body of growing lambs of the breed German Merino Landsheep

A growth experiment with 108 lambs (breed: German Merino Landsheep) was carried out to examine the effect of gender, body weight (BW) and feeding intensity on the deposition of Fe, Zn, Cu and Mn in the empty body (whole animal minus contents of the gastrointestinal tract and bladder). The lambs (50% female and 50% male animals) were fed at three feeding levels ('low', 'medium' and 'high' by varying daily amounts of concentrate and hay) and slaughtered at different final BWs (30, 45 or 55 kg). Six male and six female animals were killed at a BW of 18 kg representing the animals' BW at the beginning of the comparative slaughter experiment. There were significant main effects for the treatments growth rate and final weight on the daily rate of accretion of the trace elements examined. Feeding intensity had a marked influence on the accretion rate for Fe (P < 0.001), Zn (P < 0.001), Cu (P < 0.001) and Mn (P = 0.003). With increasing feeding intensity (low, medium, high) the daily deposition of these trace elements increased (4.4, 5.2, 6.6 mg/day for Fe; 4.9, 5.5, 6.9 mg/day for Zn; 0.20, 0.36, 0.44 mg/day for Cu; 0.14, 0.16, 0.21 mg/day for Mn). Heavier final BW led to increased daily retention of Zn (P < 0.001) and Mn (P = 0.002). Gender had a marked influence only on the accretion rate for Zn (P < 0.001). Ram lambs had a higher daily deposition of this element than female lambs. Related to 1000 g empty body gain, the following concentrations were found for the trace elements examined: Fe 26.1 mg, Zn 30.0 mg, Cu 1.41 mg and Mn 1.04 mg. A feeding influence was given for Zn (P < 0.001) and Cu (P = 0.039). Feeding level low had higher Zn and lower Cu concentrations. Male animals showed less Fe (P < 0.001) and Zn (P = 0.034) per kg empty body gain than females.

Bodily variability of zinc natural isotope abundances in sheep

Evidence is growing that the range of zinc stable isotope compositions, represented by the deviation of (66)Zn in permil units relative to a standard and expressed as delta(66)Zn, is larger in organic matter than in inorganic material. This study reports the variations of delta(66)Zn in various organs of sheep raised on a controlled diet. Zinc was purified by anion-exchange chromatography. The Zn concentrations and Zn stable isotope compositions were determined by quadrupole inductively coupled plasma mass spectrometry and multi-collector inductively coupled plasma mass spectrometry, respectively. The data show that delta(66)Zn variability exceeds 1 per thousand, with bone, muscle, serum and urine enriched in the heavy isotopes, and feces, red blood cells, kidney and liver enriched in light isotopes, all relative to the diet value. The (66)Zn enrichment of the circulating serum reservoir is likely to take place in the digestive tract, probably through the preferential binding of lighter isotopes with phytic acid, which is known to control the uptake of metallic elements. Mass balance calculations suggest that the (66)Zn depletion between diet and feces, which is not balanced by any other outward flux, leads to a secular isotopic drift in serum. A simple time-dependent two-box model, involving the gastro-intestinal tract on the one hand and the muscle and bone on the other, predicts that the maximum (66)Zn enrichment, which equals the difference in delta(66)Zn between diet and bulk (approximately 0.25 per thousand), is reached after about ten years. Therefore, a better understanding of the variations of natural abundance of Zn isotopes in animals and humans will probably bring new perspectives for the assessment of their Zn status.

The Cu, Mn and Zn concentration of sheep wool: influence of washing procedures, age and colour of matrix

No standard or wholly proven method to determine the trace metal status of human or animal 'hair' yet exists. It is well known that hair-metal concentrations are highly influenced by washing procedures applied before analysis. A novel method to determine the efficiency of washing procedures at removing exogenous contaminants was devised. It was shown that suitability of washing procedures was element-specific and increased sonication time during washing progressively removed more Mn and Zn from sheep wool. The efficiency of exogenous contaminant removal by including sonication during washing was also dependent on the efficiency of procedures under study. The Cu, Mn and Zn concentration, and thus exogenous contaminant level, of sheep wool increased in tandem with its age. Additionally, Cu and Zn concentrations of black wool were significantly higher than white wool: a relationship ascribed to melanins. This investigation shows the necessity to standardise procedures used during analysis of 'hair' fibres, and to assess each washing procedure for each element before performing routine analysis.

Trace Mineral Profile in Blood and Hair from Cattle Environmentally Exposed to Lead and Cadmium Around Different Industrial Units

The present investigation was carried out to assess the trace mineral profile in blood and hair from cows environmentally exposed to lead and cadmium and to examine if these toxic heavy metals in blood and hair could affect blood copper, cobalt, zinc and iron concentrations and their accumulation in hair. Respective blood and tail hair samples were collected from adult cows above 3 years, reared in different industrial localities. Samples were also collected from urban areas with small industrial units (n = 55) and areas supposed to be free from pollution. The concomitant exposure of animals to both the heavy metal pollutants was not recorded in either of the industrial or urban locality. Blood lead was significantly (P < 0.01) correlated with blood copper (r = -0.339), cobalt (r = -0.224) and iron (r = -0.497). The increasing blood lead concentrations, irrespective of area of collection of samples, was associated with declining blood copper and iron, and cows with blood lead level above 0.60 mug/ml had significantly (P < 0.05) lower blood copper and iron. The higher blood lead but not cadmium significantly influenced the accumulation of lead (r = 0.323, P < 0.01) and cadmium (r = 0.204, P < 0.01) in hair possibly leading to significantly (P < 0.05) higher accumulation of both lead and cadmium in hair from cattle around lead-zinc smelters and closed lead-cum-operational zinc smelter, where blood cadmium level was comparable with that from unpolluted area. Concentration of zinc (r = 0.237, P < 0.01) and iron (r = 0.183, P < 0.01) but not copper and cobalt in tail hair was significantly influenced by their respective blood concentration. Both the hair lead and cadmium had a significant (P < 0.01) positive correlation with hair copper (r = 0.234, 0.294), zinc (r = 0.489, 0.775), and iron (r = 0.385, 0.643) concentrations. Thus, it is concluded from the present study that the higher blood lead concentrations in cattle irrespective of locality/industrial operations areas affected trace elements profile in blood and hair.

Effects of cadmium in herbage on the apparent absorption of elements by sheep in comparison with inorganic cadmium added to their diet

A meta-analysis of existing scientific literature recently suggested that Cd is absorbed more efficiently by sheep if it is in the organic form in grass, than if it is added as an inorganic supplement to the diet. We tested this experimentally by feeding sheep grass from contaminated soil, compared with uncontaminated grass and with Cd added to the diet. To produce contaminated herbage, Cd nitrate was added to soil in 11 lysimeters sown with perennial ryegrass, with a further 11 lysimeters receiving no Cd to produce uncontaminated herbage. In the Cd-treated lysimeters, soil had increased exchangeable K, Mg, and Ca, leachate had increased K, Mg, Ca, Na, and P, grass had increased Cd and reduced Mg, Na, P, Mn, Fe, Cr, Al, and Ni, and there was some reduction in grass yield compared with untreated lysimeters. Grass from Cd-treated or untreated lysimeters was fed to groups of 12 ewes for 2 days, with Cd intake equated by adding Cd nitrate to the concentrate feed of ewes receiving the uncontaminated grass. The apparent absorption of Cd, Zn, Mo, Cr, and Al was increased for ewes receiving Cd-enriched grass, and apparent absorption of Cu was reduced, compared to those receiving supplementary inorganic Cd. Most of the unabsorbed Cd was excreted in feces within 4 days of feeding. The ewes consuming Cd in grass had increased B concentrations in their urine, possibly due to adverse effects of Cd on kidney function. Finally, the ewes were offered a choice of the two herbages and they ate significantly more of the uncontaminated grass. It is concluded that the apparent absorption of Cd and other heavy metals by sheep in a short-term experiment was greater when Cd was in the grass than when the Cd was added in in an inorganic form and that sheep partially avoided herbage with a high Cd concentration.