Experimental laboratory diagnostic and residual toxicological studies in young cocks after feeding mercury-disinfected seed with and without selenium supplementation

A feed loading experiment was applied in 2 phases to 45 young cocks over 12 weeks, using 1.2 (N, N-bis/methylmercury/-p-toluolsulphamide)-dressed wheat (50% of base ration). The experimental animals were White-Leghorn laying hybrids. Investigations were conducted to study the effects of exclusive exposure to mercury and those of mercury with addition of 0.2 mg of sodium selenite/l drinking water on biochemical parameters (calcium, phosphorus, total protein, albumin, creatinine, urea, activity of alkaline phosphatase, hematocrit, hemoglobin, and leucocyte count) as well as on parameters relating to toxicological residues (selenium and mercury levels in liver, musculature, and kidneys). Statistically secured differences were found to exist between the experimental groups with regard to selenium and mercury in the liver and mercury concentrations in kidneys. These data have shown that the problem of residualisation cannot be solved by selenium supplementation in parallel to methylmercury loading. The results recorded are likely to confirm the need for a general ban on feeding mercury-dressed seed.     

Trace element levels in liver and kidney from cattle, swine and poultry slaughtered in Canada.

Levels of arsenic, cadmium, copper, mercury and lead were determined in approximately 650 samples of liver and kidney from cattle, swine and poultry slaughtered in Canada during 1979-81. In addition zinc levels were determined in livers and kidneys from swine, and selenium and zinc levels were determined in the livers and kidneys from cattle. Depending on the element several methods of atomic absorption spectroscopy were used to analyze samples including flame, hydride generation, cold vapour generation and graphite furnace atomization. Analyses were also done by plasma emission spectroscopy. Levels of arsenic over 2.0 micrograms/g were detected in 0.9% of swine livers and 0.3% of swine kidneys. Cadmium levels higher than 1.0 micrograms/g were detected in 0.3% of cattle livers, 10.8% of cattle kidneys, 1.8% of swine kidneys, 0.4% of poultry livers and 0.3% of poultry kidneys. Levels of copper over 150 micrograms/g were detected in 0.4% of cattle and swine livers. Levels of lead over 2.0 micrograms/g were detected in 1.4% of poultry livers and 1.6% of poultry kidneys. The highest level of mercury detected in all species was 0.25 micrograms/g and the highest level of selenium was 1.9 micrograms/g. Zinc levels of over 100 micrograms/g were detected in 1.7% of cattle livers, 0.2% of cattle kidneys and 5.0% of swine livers.     

Mercury and selenium in wild mink (Mustela vision) from Norway

Levels of mercury, methylmercuri and selenium were determined in liver samples from wild mink (Mustela vision) caught in the Norwegian countries of Rogaland (38 samples), Sogn og Fjordane (15 samples) and Hedmark (18 samples). The average mercury levels from these counties were 2.6, 3.1 and 2.1 micrograms Hg/g wet weight, respectively. No significant differences in mercury levels were found. The methyl mercury levels (MeHg) were determined in 30 samples. A very strong positive correlation between total mercury (Hg) and methyl mercury (r = 0.91, P less than 0.001) was found. The average methyl mercury level was 35 per cent of total mercury. This indicates that wild mink has the ability to demethylate mercury. The selenium levels were determined in 35 samples. A strong positive correlation between the levels of total mercury and selenium (r = 0.87, P less than 0.001) was found. There was no correlation between age or nutritional condition and mercury level. In the present study mink was examined to see of it could be recommended as an indicator species for monitoring the local environment for mercury contamination. No definite answer to this question could be found. The study did reveal, however, that in all the counties studied there are individuals that are considerably contaminated with mercury.     

Study of the soil-plant (carrot)-animal cycle of nutritive and hazardous minerals in a rabbit model.

Carrots were grown on soils polluted by heavy metal salts. Each particular microelement reached a high concentration [molybdenum (Mo) 39.00, cadmium (Cd) 2.30, lead (Pb) 4.01, mercury (Hg) 30.00, and selenium (Se) 36.20 mg/kg dry matter] in the carrot. In a metabolic balance trial conducted with 15 male and 15 female New Zealand White rabbits, the control animals (n = 5) were fed ad libitum with concentrate as basal diet, while the other rabbits received the basal diet and carrots containing the particular microelement. Blood samples were taken to determine the activity of serum enzymes. To investigate the metabolism of Mo, Cd, Pb, Hg and Se, samples were taken from the heart, liver, lungs, kidneys, spleen, ovaries/testicles, entire digestive tract, adipose tissue, femur, hair, faeces and urine. Carrot had significantly higher digestibility for all nutrients than the rabbit concentrate. Carrot samples of high Pb content had the lowest digestibility of crude protein. The microelements differed in their rate of accumulation in the organs examined: Mo and Cd accumulated in the kidneys, Pb in the kidneys, liver, bones and lungs, Hg in the kidneys and liver, while Se in the liver, kidneys and heart. The proportions of microelements eliminated from the body either via the faeces and urine (Mo 80.18% and Se 47.41%) or via the faeces (Cd 37.86%, Pb 66.39%, Hg 64.65%) were determined. Pathohistological examination revealed that the rate of spermatogenesis was reduced in the Mo, Cd, Pb and Hg groups compared to the control. Lead, Cd and Hg intake resulted in a considerable decrease in gamma-glutamyltransferase (GGT) and in an increase of alkaline phosphatase (ALP) activity because of damages to the kidneys and bones. All experimental treatments decreased the activity of cholinesterase (CHE) because of lesions in the liver.     

Fluorometric Selenium Determinations in the Liver of Normal Pigs and in Pigs Affected with Nutritional Muscular Dystrophy and Liver Dystrophy

The selenium concentration of livers and kidneys in normal pigs and in pigs affected with nutritional muscular dystrophy (NMD) and liver dystrophy (LD) was determined. The kidney values showed great variation in normal pigs. The young pigs generally had the lowest levels. The liver values were less scattered.In NMD and LD the liver contained about 0.2 ppm of selenium on the average, whereas normal livers contained about 1.2 ppm. Kidneys showed corresponding differences. This is in good agreement with the favourable results obtained with selenium therapy.     

Levels of trace elements in liver from Norwegian moose, reindeer and red deer in relation to atmospheric deposition

The levels of antimony, arsenic, cadmium, copper, lead, mercury, molybdenum, selenium and zinc were determined in liver of moose, reindeer and red deer from differen localities in Norway. Reindeer had considerably higher levels of mercury, lead and arsenic than moose and red deer. These findings are considered to be related to differences in feeding habits since reindeer on highland plateaus feed mainly on lichens which have been shown to accumulate trace elements. The levels of arsenic, and to some extent also selenium and cadmium, in moose and reindeer liver showed a north-south gradient closely related to the regional distribution of these elements in the forest moss. As regards lead, a north-south gradient and a relationship to moss levels, were found in moose liver only. It therefore seems that atmospheric deposition of the elements mercury, lead, arsenic, cadmium and selenium contribute to the body burden of these elements in cervides in Norway. There was no evidence of these elements accumulating to toxic levels.     

Evaluation of selenium status and its distribution in organs of free living foxes (Vulpes vulpes) from an Se deficient area

The objective of the study was to determine selenium status and its distribution in the organs of free living foxes from selenium deficient areas of north-western Poland. Samples of organs harvested from 40 foxes shot during the 2008-2009 hunting seasons served as experimental material. Selenium concentration in the organs was determined spectrofluorometrically. Selenium distribution in tissues depends largely on its dietary content. Our study indicated that concentrations of selenium in the examined organs followed the order: kidney>liver>spleen>lung>heart and kidneys were the organ with the highest retention of this element. Mean selenium concentration in fox kidneys was 0.60 +/- 0.15 microg/g wet weight. Several times less selenium on average was found in the liver (0.27 +/- 0.09 microg/g w.w.), lungs (0.17 +/- 0.06 microg/g w.w.), spleen (0.19 +/- 0.06 microg/g w.w.) and heart (0.13 +/- 0.05 microg/g w.w.). All the animals studied were deficient in selenium.     

Retention of Selenium in Kidneys,Liver and Striated Muscle After Prolonged Feeding of Therapeutic Amounts of Sodium Selenite to Pigs

Sodium selenite was mixed in a commercial pig food so as to increase the original selenium content (0.126 ppm) by 1.2 ppm. The supplemented food was given to 7 pigs during 78 days. A control group of as many pigs was given the non-supplemented commercial food. The pigs were killed, starting 4 hours after the last selenium-supplemented food had been given and then with intervals during the next 14 days. Small but significant increases of tissue selenium were noticed in liver and striated muscle as compared with the control animals. The kidneys showed no increase.     

Infleuce of dietary levels of vitamin E and selenium on tissue and blood parameters in pigs.

Eighteen barrows approximately three weeks of age were used in a 3 X 3 factorial arrangement to investigate the effect of level of supplemental vitamin E and selenium on tissue and blood parameters. Tissue selenium concentrations increased in a quadratic manner with increased selenium intake with kidney tissue containing considerably greater concentrations than liver, heart or muscle. Supplementation of the diet caused a three-fold increase in serum selenium within the first week with a slight tendency to further increases in subsequent weeks. Serum vitamin E of unsupplemented pigs declined by fifty percent during the experiment, whereas supplemental vitamin E resulted in increased serum vitamin E. There was a considerable viration in percent peroxide hemolysis. Correlation of -0.63 between percent peroxide hemolysis and vitamin E intake and -0.85 between percent peroxide hemolysis and serum vitamin E were observed.     

Influence of selenium on aflatoxin B1 or crotalaria toxicity in turkey poults

This research compared the toxic effects of aflatoxin B1 and monocrotaline, the active principle of Crotalaria spectabilis, and the additive effect between aflatoxin B1 and monocrotaline in turkey poults. It was of interest whether selenium fed at dosage levels of 0.1, 5, or 10 micrograms/g of feed would protect against the toxic effect of aflatoxin and/or monocrotaline, and whether the toxicants would result in detectable residues in poult tissues. A total of 180 healthy 1-day-old male turkey poults was assigned at random to 12 treatment groups (15 birds/group). Body and liver weight losses, and low serum concentrations in total protein (TP), albumin (A), alpha-globulin (alpha G), and beta-globulin (beta G), as well as high values in gamma-globulin (gamma G), were produced in the groups fed crotalaria. Pathologic changes were induced by monocrotaline with no protection afforded by the added selenium. Low values in TP, A, alpha G, and beta G and in body and liver weights were observed in groups given the combination of aflatoxin plus crotalaria. Gross lesions were associated with an additive toxic effect and a lack of protective effect of selenium against this combination. However, higher values in TP, A, alpha G, and beta G, and liver weights in groups fed aflatoxin B1 plus selenium indicated that selenium had a protective effect against aflatoxin toxicity. Residues of aflatoxin B1 and aflatoxin M1 were found in the kidneys of poults fed aflatoxin B1; also, dehydroretronecine (the metabolite of monocrotaline) was detected in livers of poults fed Crotalaria spectabilis seeds.     

Cadmium and selenium levels in kidneys from Danish horses

The content of cadmium and selenium in horse kidneys from Jutland , Denmark, in relation to age, local geographical variation and possible relationship between the two elements has been investigated. During the winter of 1982-1983 kidneys from 50 horses were sampled and analysed for cadmium and selenium. The cadmium content of the horse kidneys was recorded in connection with the age of the horses. The cadmium level increases until the animal has reached approximately 7 years of age. At this age the cadmium concentration levels off. A significant regional difference was shown. The cadmium content is higher in horse kidneys from South and Central Jutland than in kidneys from North Jutland (Fig. 2). This geographic pattern is consistent with the one for atmospheric deposition of cadmium and cadmium content in Danish cattle kidneys from Jutland . The cadmium level in kidneys from Danish horses is considerably lower than the level in Norwegian and Swedish horse kidneys. Differences in water hardness and atmospheric deposition may explain some of this difference within Scandinavian countries. The selenium concentration shows no relationship with neither age, cadmium content nor place of rearing. So, the study did not reveal any relationship between the cadmium and selenium concentrations in horse kidneys. The high level of cadmium found in Danish horse kidneys emphasizes the importance of a prohibition against the use of the kidneys in animal and human nutrition, as proposed by others.     

Poisoning in ferrets by tissues of alkyl mercury-fed chickens

Chickens were fed alkyl mercury-dressed wheat (mercury content about 8 mg/kg) for 35–44 days and were then immediately sacrificed. No signs of untoward effects were observed. Muscle of the chickens, and a minor proportion of liver, were fed to two groups of two ferrets (Mustela furo L. × M. putorius L.), the mercury content of the diet being 7 and 5 mg/kg, respectively. The ferrets of the first group died after 35 and 36 days and those of the second after 58 days.The experimental ferrets showed a marked weight loss, attributable to muscular atrophy in addition to a reduced food intake. Clinical signs appeared in two to three weeks and were primarily neurological such as ataxia, trembling and paralysis. The signs could be correlated with pronounced degenerative changes of the central and peripheral nervous systems involving mainly the cerebellum and peripheral nerves and, to a lesser extent, the cerebrum and the spinal cord. Hypoplasia of the lymphatic tissue of the spleen and degeneration of the graafian follicles were seen as well.High mercury levels were found in the kidneys, liver and brain and also in skeletal muscle and the gonads of the ferrets (Table 2). Methyl mercury constituted the major part of the tissue mercury in the ferrets (as well as in the chickens).The results provide direct evidence of the transfer and accumulation of alkyl mercury in a toxic form through a food chain. The ecological implications are discussed.     

The lowering effect of high copper intake on selenium retention in weanling rats depends on the selenium concentration of the diet

The question addressed was whether the influence of dietary copper concentration on selenium metabolism depends on the amount of selenium in the diet. Weanling, male rats were fed purified diets containing either 1 (low), 4 (normal) or 42 (high) mg Cu/kg diet and either 0.03 (low), 0.05 (normal) or 1.0 (high) mg Se/kg diet in a 3² factorial design. Extra copper was added to the diets in the form of CuSO₄ · 5H₂O and selenium as Na₂SeO₃ · 5H₂O. In rats fed either the low or normal amounts of selenium, higher intakes of copper decreased the apparent intestinal selenium absorption and increased urinary selenium excretion. The effects of copper on selenium absorption, excretion and retention were not seen in rats fed the high-selenium diets. An increase in dietary copper concentrations elevated selenium concentrations in the liver and kidneys, but slightly lowered those in the spleen of rats that were fed the diets with the normal level of selenium. In rats that were fed the diets with either low or high selenium concentration, copper intake had no effect on organ selenium concentrations. Glutathione peroxidase activity in erythrocytes was raised by feeding the diets which contained either normal or high copper content instead of those that were low in copper. It is concluded that the amount of selenium in the diet determines whether or not an increase in dietary copper concentration affects selenium metabolism.     

维生素E和氯化汞对比目鱼生长性能和汞生物学蓄积的交互作用

本研究进行6周的饲养试验,评估维生素E(VE)和汞对比目鱼生长性能和汞生物学蓄积的影响。试验采用2×3因子设计,将360条比目鱼随机分到6组,每组3个重复,每个重复20条鱼。对照组饲喂基础日粮,处理组分别在基础日粮中添加100、200 mg/kg VE、15 mg/kg汞、15 mg/kg汞+100 mg/kg VE、15 mg/kg汞+200 mg/kg VE。结果显示,日粮添加汞显著抑制比目鱼的增重、特定生长率、饲料效率和蛋白效率(P<0.05),而VE显著改善增重(P<0.05)。汞和VE对试验期间比目鱼的存活率无显著影响(P>0.05)。日粮补充VE对比目鱼粗脂肪、水分有一定影响。VE显著降低肌肉、肝脏和肾脏汞含量(P<0.05),但日粮添加汞降低了组织VE含量(P<0.05)。汞显著降低了比目鱼机体二十碳五烯酸和二十二碳六烯酸含量(P<0.05),补充VE后显著改善了机体亚麻酸和二十碳五烯酸含量(P<0.05)。结果表明,日粮中添加VE对比目鱼生长发育具有促进作用,同时有降低无机汞在机体蓄积的潜在作用。     

硒对汞致抗氧化系统损伤的拮抗作用

选用健康雏鸡250只作实验动物（对照组、中毒组、3个水平的硒保护组），研究汞对血液、组织中GSH－Px活性和LPO含量的影响以及硒与汞之间的相互作用效应。实验结果表明：汞可显著降低血清、组织中GSH－Px活性（P＜0.01），引起动物组织器官脂质过氧化，致使血清、组织中LPO含量显著增高（P＜0.01），且有时间－效应关系。从而说明汞能降低机体的抗氧化功能，损伤抗氧化系统；硒对汞致抗氧化系统的损伤具有拮抗作用。     

硒与维生素E对鸡马杜霉素急性中毒的保护作用

在实验条件下用7mg/kg bw.剂量的马杜霉不诱发鸡急性中毒，处理组鸡在给马杜霉素前给予硒（0.2mg/kg bw.剂量，内服）－维生素E（每kg饲料含200mg)7d，在给马杜霉素后给予硒（0.2mg/kg bw.剂量，内服）－维生素E（200mg/kg bw.剂量，肌注）4d，中毒组在给马杜霉素前后不给任何硒和维生素E，对照组既不给马杜霉素，也不给硒与维生素E。结果是：处理组鸡的死亡率显著低于中毒组（P＜0.05），且病鸡恢复比中毒组快。处理组的肝脏、心肌、骨骼肌的出血与变性比中毒组轻，但处理组与中毒组的肾脏的出血与变性的程度相似；处理组的血清GOT值、肝脏的脂质过氧化物的含量、肝脏过氧化氢酶的性均显著低于中毒组；但处理组的血清CK值与中毒组相比无显著性差异。结果表明硒与维生素E对鸡马杜霉素急性中毒有较好的保护作用。     

硒和碘营养对蛋鸡不同组织抗氧化酶活性的影响

本试验旨在探讨饲粮中添加不同剂量的硒和碘对蛋鸡心脏、肝脏、脾脏和甲状腺中几种抗氧化酶活性的影响。288只33周龄的新罗曼蛋鸡,饲喂添加不同剂量硒和碘(0,0;0.2,0:0,0.2:0.2,0.2mgkg)的日粮12周,试验结果如下:硒缺乏时,心脏和肝脏中的GSHPx活性下降(P=0.073);碘缺乏时,心脏和肝脏中的CAT活性下降(P=0.055,P=0.097),肝脏中的GSHPx活性降低(P=0.093);硒碘互作对心脏(P<0.01)和肝脏(P<0.05)中的TSOD和CAT活性影响显著,对脾脏中的TSOD(CAT+GSHPx)值影响极显著(P<0.01)。结果表明:碘能够影响肝脏中含硒酶的活性,硒碘的互作能够影响心脏、肝脏和脾脏的抗氧化酶活性。     

The activity and properties of fructose-1,6-diphosphatase in various tissues (Liver, Kidneys, skeletal muscle, small intestine mucosa) in swine]

The following parameters are recommended for activity determination of FDPase by release of inorganic phosphate at 37 degrees C of enzyme from liver and kidneys of swine: pH 7.5, 2 mMol concentration of fructose-1,6-diphosphate, 5 mMol concentration of Mg ions, and ten minutes of incubation. When the activity of FDPase was analysed with temperatures of 22 degrees C, and 45 degrees C, rises were recorded up to the highest temperature. ADTA was strongly activating along with 2 mMol of Mg ions in a test arrangement of 5 mMol concentration. Manganese, zinc, and cobalt ions are strong activators even in low concentrations (0.2 or 1.0 mMol), whereas copper, cadmium, and mercury ions are strong inhibitors of the enzyme. Average activities of FDPase were analysed by means of the optical test in the liver and kidneys of fetuses aged 98 days. They were 1.79 or 0.38 units in one gram of tissue. In pigs for slaughter they had been 2.06 or 3.58 units in one gram of tissue.     

Development of goitre and enterohepatonephropathy in Nubian Goats fed with pearl millet (Pennisetum typhoides)

We present the first reported study of Pearl millet (Pennisetum typhoides) goitrogenesis and enterohepatonephropathy in 5-9-month-old Nubian goats of either sex. The goats were fed 0.25 or 1 g millet per kg body weight per day for 62 days. The effects on thyroid follicles, intestines, liver and kidneys are described and correlated with clinical signs, changes in serum and tissue iodine and selenium concentrations and alterations in serum aspartate transaminase, gamma glutamyl transferase, total protein, total lipids and other constituents and haematological values.     

Liver copper, selenium and vitamin B12 concentrations in farmed and feral red deer (Cervus elaphus)

AIM: To compare liver copper, selenium and vitamin B12 concentrations in red deer of farmed and feral origin. METHODS: Liver samples were collected from red deer at a South Island deer slaughter premise and a game packing house in November 2000. The site of origin and age of each animal were recorded. A subsample of 107 livers was selected (n=5-10 per site of origin and age category) from farmed deer from central Canterbury, Nelson and Westland, and from feral deer from north, central and south Westland. Samples were analysed for copper, selenium and vitamin B12 concentrations and reported on a wet-matter basis. RESULTS: Mean liver copper concentrations for farmed and feral yearlings were 267 and 889 micromol/kg, respectively, and for farmed and feral adults were 206 and 677 micromol/kg, respectively. Liver copper concentrations were lower for farmed than for feral deer (p<0.001) and for feral adults than for feral yearlings (p=0.002). Mean liver selenium concentrations in farmed and feral yearlings were 2050 and 1539 nmol/kg, respectively, and in farmed and feral adults were 1938 and 1625 nmol/kg, respectively. Liver selenium concentrations varied significantly between regions and overall, farmed deer had higher liver selenium concentrations than feral deer (p=0.04). Mean liver vitamin B12 concentrations in farmed and feral yearlings were 456 and 742 nmol/kg, and for farmed and feral adults were 428 and 869 nmol/kg, respectively. Liver vitamin B12 concentrations were lower for farmed than for feral deer (p<0.001). CONCLUSION: Feral deer had higher liver copper and vitamin B12 concentrations and lower liver selenium concentrations than farmed deer in the regions studied.