Gizzerosine,a New Toxic Substance in Fish Meal,Causes Severe Gizzard Erosion in Chicks

“Black vomit” is a serious disease in chicks and is caused by some kinds of fish meal in the diet. However, the causative compound has not been identified. In the present study, a new substance, 2-amino-9-(4-imidazolyl)-7-azanonanoic acid, has been isolated from mackerel meal and named Gizzerosine. This compound caused severe gizzard erosion in chiks within a week when it was fed to them at the level of 2.2 ppm in the diet. Gizzerosine is produced during fish meal manufacturing by the reaction between histidine and protein in the fish meat. The discovery of Gizzerosine raises a new problem in food chemistry and animal nutrition.     

Platelet Selenium Indices as Useful Diagnostic Surrogate for Assessment of Selenium Status in Lambs: an Experimental Comparative Study on the Efficacy of Sodium Selenite vs. Selenium Nanoparticles

Biological Trace Element Research - Unlike in human medicine, information on the platelet selenium (Se) concentration and glutathione peroxidase (GPx) activity, as potential biomarkers of Se...     

Selenium and Glutathione Peroxidase Levels in Lambs Receiving Feed Supplemented with Sodium Selenite or Selenomethionine

Twenty-one 6 months old female lambs were divided into 7 groups and fed a basal diet containing 0.13 mg Se/kg. The basal diet was further supplemented with 0, 0.1, 0.5 or 1.0 mg Se/kg either as sodium selenite or as selenomethionine, and was fed for 10 weeks. Both feed additives produced an increase in the selenium concentration in the tissues analysed. Significant correlations were found between the concentrations of selenomethionine or sodium selenite added to the feed and the subsequent tissue levels. However, the selenium levels seemed to plateau at approximately 0.5 mg Se/kg of supplemented sodium selenite. The total glutathione peroxidase (GSH-Px) activity of the tissues increased when the selenium supplementation increased from 0 to 0.1 mg/kg for both selenium compounds. With further increase in selenium supplementation the GSH-Px activity in the tissues plateaued except in the blood where the activity continued to rise with increasing selenomethionine supplementation. The selenium dependent GSH-Px activity in the liver rose with increasing selenomethionine supplementation, but approached a plateau when 0.1 mg Se/kg as sodium selenite was added to the feed. The selenium concentration in whole blood responded more rapidly to the selenium supplementation than did GSH-Px activity. The experiment indicates that the optimal selenium concentration in the feed is considerably higher than 0.1 mg Se/kg, and that selenium levels of 1.0 mg/kg in the feed do not result in any risk for the animals or the consumers of the products.     

Lower Selenoprotein T Expression and Immune Response in the Immune Organs of Broilers with Exudative Diathesis Due to Selenium Deficiency

The objective of the present study was to investigate whether dietary selenium (Se) deficiency would affect the expression of selenoprotein T (SelT) and immune response in the immune organs of broilers. Changes in expression of inflammatory cytokines and oxidative stress response caused by Se deficiency can lead to organism damage, which in turn leads to immune response. Sixty (1-day-old) broilers were divided into the control group and Se-deficiency group. Animal models with exudative diathesis were duplicated in the broilers by feeding them Se-deficient diet for 20 days. After the Se-deficient group exhibited symptoms of exudative diathesis, all the broilers were euthanized, and their immune organs were taken for analysis. The tissues including spleen, bursa of Fabricius, and thymus were treated to determine the pathological changes (including microscopic and ultramicroscopic), the messenger RNA (mRNA) expression levels of SelT and its synthetase (SecS and SPS1), cytokine mRNA expression levels, and antioxidant status. The microscopic and ultramicroscopic analyses showed that immune tissues were obviously injured in the Se-deficient group. The mRNA expression of SelT was decreased compared with that in the control group. Meanwhile, the mRNA expression levels of SecS and SPS1 were downregulated. In the Se-deficient group, the mRNA expression levels of IL-1R and IL-1β were higher than those of three control organs. Additionally, the IL-2 and INF-γ mRNA expression levels were lower than those of the control group. The activity of CAT was decreased, and the contents of H₂O₂ and •OH were increased due to Se deficiency. Pearson method analysis showed that the expression of SelT had a positive correlation with IL-2, INF-γ, SecS, and SPS1 and a negative correlation with IL-1R and IL-1β. In summary, these data indicated that Se-deficient diet decreased the SelT expression and its regulation of oxidative stress, and it inhibited a pleiotropic mechanism of the immune response.

     

Selenium Concentrations in Tissues and Eggs of Growing and Laying Chickens Fed Sodium Selenite at Different Levels

Growing and laying chickens were fed graded levels of selenium in the form of sodium selenite. One day old Norwegian bred broiler chickens and 20 weeks old Norwegian bred White Leghorn chickens were divided into 5 groups each and fed a basal diet supplemented with 0, 0.1, 1.0, 3.0 or 6.0 μg Se/g for 6 and 31 weeks, respectively. At the end of the experiments significantly higher concentrations of selenium were found in the groups fed 1.0, 3.0 and 6.0 μg Se/g diet compared to the control group. Correspondingly higher concentrations of selenium were found in egg samples. The increase in egg yolk selenium was much higher than in egg white. Significant correlations were found between the amounts of selenium added to the ration and the selenium concentrations in liver, kidney, breast muscle, egg white, yolk and homogenized egg. There were no differences in body weight gain and egg production between the groups. A possible positive contribution to animal and human health of selenium supplementation of animals’ diet above the required level is discussed.     

Nanoparticles of Selenium as Species with Stronger Physiological Effects in Sheep in Comparison with Sodium Selenite

The present study was designed to compare the effects of nano red selenium and sodium selenite on the antioxidative activities of neutrophils and the hematological parameters in sheep. Fifteen sheep were randomly allocated into three groups. Groups 1 and 2 received selenium nanoparticles orally at 1 mg/kg and sodium selenite at 1 mg Se/kg for 10 consecutive days; group 3 served as the control. To assess the degrees of oxidative stress and of lipid peroxidation of the cellular membranes, the levels of thiobarbituric acid reactive substances (TBARS) were determined in serum samples that were collected at different supplementation intervals, i.e., after 0, 10, 20, and 30 days. In addition, hematological parameters in the serum samples were measured by routine procedures. It was found that TBARS levels in groups 1 and 2 were significantly higher on days 20 and 30 compared to the basal level on day 0. It was also found that on day 30, the TBARS activities in both treated groups were significantly higher than those of the controls (P < 0.05). These findings may explain the seemingly paradoxical effects of supplemental selenium on the indicators of oxidative stress, as the levels of TBARS were generally expected to decrease in the presence of selenium. There were no significant differences between the PCV and RBC values in the three groups. The white blood cell count (WBC) in group 1 showed a significant increase on days 20 and 30 in comparison with the control group. However, in group 2, there was a significant increase of the WBC value just on day 20 in comparison with the control group. Also, there were significant increases of the neutrophil counts and significant decreases of the lymphocyte counts on day 10 in group 1, in comparison with those in group 2 and controls, and on days 20 and 30 in groups 1 and 2 in comparison with those in the control group.     

The Effect of Selenite Ions on Growth and Selenium Accumulation in Spirulina platensis

Selenium accumulation and the growth of cyanobacterium Spirulina platensis (Nordst.) Geitl. were studied in a culture with sodium selenite-supplemented nutritional medium. Selenite concentrations below 20 mg/l did not inhibit the growth of S. platensis. The addition of 30 mg/l of this salt somewhat decreased the growth rate during the linear growth phase, induced the earlier suspension transition to the steady-state phase, and substantially lowered the highest optical density of the suspension. However, even at 170 mg/l Na₂SeO₃, the culture still demonstrated a capacity for growth. The content of selenium in the cells depended directly on its concentration in the medium, up to the lethal level. At high selenium concentrations (100–170 mg/l), S. platensis reduced Se(IV) up to Se(0). The latter was secreted onto the cell surface and into the cultural medium. The high concentrations of Na₂SeO₃ acidified the cytoplasmic pH as was measured by ³¹P-NMR spectroscopy. At the same time, the content of protein on a dry weight basis decreased and that of carbohydrates and lipids somewhat increased, just as was observed in S. platensis cells under other stress factors. In the presence of 20 mg/l Na₂SeO₃, the selenium content in the biomass increased by 20000 times as compared to that in the control cells, whereas the biochemical composition of biomass did not change. In this case, the selenium was incorporated almost completely in the protein fraction. The selenium concentration in this fraction increased more significantly when the sulfur content was lowered in the medium.     

Form of Selenium in Selenite Enrichment Media for Isolation of Salmonellae

Selenite-F and selenite-cystine media, commercially available for the routine isolation of salmonellae, were treated by anion exchange chromatography to separate the selenium from other components of the media. A chemical assay, based on an ascorbic acid reduction, showed that the selenium was all in the form of selenite.     

亚硒酸钠对小麦幼苗中谷胱甘肽过氧化物酶和谷胱甘肽转硫酶活性以及谷胱甘肽含量的影响

用1.0 mg·L-1的亚硒酸钠根施小麦幼苗,测定亚硒酸钠对谷胱甘肽过氧化物酶和谷胱甘肽转硫酶活性以及还原性谷胱甘肽含量的结果表明,外源亚硒酸钠对麦苗地上部的谷胱甘肽过氧化物酶和谷胱甘肽转硫酶活性均有诱导作用,使麦苗体内的谷胱甘肽含量水平增加.     

The Influence of Supplements of Selenite,Selenate and Selenium Yeast on the Selenium Status of Dairy Heifers

The aim of the study was to define possible differences between selenite, selenate and selenium yeast on various aspects of selenium status in growing cattle. Twenty-four Swedish Red and White dairy heifers were fed no supplementary selenium for 6 months. The basic diet contained 0.026 mg selenium/kg feed dry matter (DM). After the depletion period the animals were divided into 4 groups; group I–III received 2 mg additional selenium daily as sodium selenite, sodium selenate, and a selenium yeast product, respectively. Group IV, the control group, received no additional selenium. The total dietary selenium content for groups I–III during the supplementation period was 0.25 mg/kg DM. After the depletion period the mean concentration of selenium in blood (640 nmol/l) and plasma (299 nmol/l) and the activity of GSH-Px in erythrocytes (610 µkat/l) were marginal, but after 3 months of supplementation they were adequate in all 3 groups. The concentration of selenium in blood and plasma was significantly higher in group III than in groups I and II, but there was no significant difference between groups I and II. The activity of GSH-Px in erythrocytes did not differ between any of the supplemented groups. The animals in the control group had significantly lower concentrations of selenium in blood and plasma and lower activities of GSH-Px in erythrocytes than those in the supplemented groups. The activity of GSH-Px in platelets was also increased by the increased selenium intake. There was no difference in the concentration of triiodothyronine (T3) between any of the groups, but the concentration of thyroxine (T4) was significantly higher in the unsupplemented control group.     

Comparative Mycotoxin Profiles of Gibberella zeae Populations from Barley, Wheat, Potatoes, and Sugar Beets

Gibberella zeae is one of the most devastating pathogens of barley and wheat in the United States. The fungus also infects noncereal crops, such as potatoes and sugar beets, and the genetic relationships among barley, wheat, potato, and sugar beet isolates indicate high levels of similarity. However, little is known about the toxigenic potential of G. zeae isolates from potatoes and sugar beets. A total of 336 isolates of G. zeae from barley, wheat, potatoes, and sugar beets were collected and analyzed by TRI (trichothecene biosynthesis gene)-based PCR assays. To verify the TRI-based PCR detection of genetic markers by chemical analysis, 45 representative isolates were grown in rice cultures for 28 days and 15 trichothecenes and 2 zearalenone (ZEA) analogs were quantified using gas chromatography-mass spectrometry. TRI-based PCR assays revealed that all isolates had the deoxynivalenol (DON) marker. The frequencies of isolates with the 15-acetyl-deoxynivalenol (15-ADON) marker were higher than those of isolates with the 3-acetyl-deoxynivalenol (3-ADON) marker among isolates from all four crops. Fusarium head blight (FHB)-resistant wheat cultivars had little or no influence on the diversity of isolates associated with the 3-ADON and 15-ADON markers. However, the frequency of isolates with the 3-ADON marker among isolates from the Langdon, ND, sampling site was higher than those among isolates from the Carrington and Minot, ND, sites. In chemical analyses, DON, 3-ADON, 15-ADON, b-ZEA, and ZEA were detected. All isolates produced DON (1 to 782 μg/g) and ZEA (1 to 623 μg/g). These findings may be useful for monitoring mycotoxin contamination and for formulating FHB management strategies for these crops.     

The Effects of Oral Consumption of Selenium Nanoparticles on Chemotactic and Respiratory Burst Activities of Neutrophils in Comparison with Sodium Selenite in Sheep

The present study was designed to compare the effects of nano-selenium and of sodium selenite on the chemotactic and respiratory burst activities of neutrophils in sheep. Fifteen sheep were randomly divided into three groups. Groups 1 and 2 received selenium nanoparticles (1 mg/kg) or sodium selenite (1 mg/kg) orally, respectively, for ten consecutive days, and the third group was considered as the control. To determine the chemotactic and respiratory burst activities of the neutrophils, the leading front assay and the NBT test were used on heparinized blood samples that were collected at different intervals (days 0, 10th, 20th, and 30th). The results obtained showed that the chemotactic activities in groups 1 and 2 increased significantly on the 10th, 20th, and 30th day, compared to day 0, and on the 20th day in comparison with the 10th day, while in group 2, there was a significant decrease on the 30th day compared to the 20th day. The chemotactic activities in group 1 were significantly higher than in group 2 on the 10th day and in the control group on the 10th, 20th, and 30th day, but the chemotactic activities in group 2 were significantly higher than those in the control group only on the 20th day. On the 30th day into the experiment, the respiratory bursts in groups 1 and 2 were significantly stronger in comparison with those at day 0. Overall, nano-selenium increased the chemotactic and respiratory burst activities more significantly than sodium selenite, which is suggestive of a stronger stimulatory effect of the Se nanoparticles on intracellular activities.     

Effect of Sodium Selenite on Gene Expression of SELF,SELW, and TGR Selenoproteins in Adenocarcinoma Cells of the Human Prostate

Selenium is an essential trace element, the deficiency of which leads to the development of several serious diseases, including male infertility, prostate cancer, etc. It has been shown that oxidative stress contributes to the progression of prostate cancer, and antioxidants such as selenium and vitamin E can significantly reduce the risk of this disease. Sodium selenite, one of the selenium compounds that induce the formation of reactive oxygen species, is considered as a potential anticancer agent. The SS concentrations that lead to a decrease in the viability of human prostate adenocarcinoma cells (line Du-145) have been selected, and the effect of sodium selenite on the expression of mRNA of the SELV, SELW, and TGR selenocysteine proteins in these cells has been analyzed.     

Development of a Procedure to Determine Standardized Mineral Availabilities in Soybean Meal for Broiler Chicks

The objective of this study was to develop a procedure for estimating the standardized mineral (calcium, Ca; phosphorus, P; copper, Cu; manganese, Mn; zinc, Zn) availabilities (SMA) in soybean meal for broilers. In experiment 1, twelve 24-day-old male chicks were used to determine the length of the pre-experimental fasting period needed to empty the total tract of feed residues. Feed was removed and excreta samples were collected for 12, 24, 36 or 48 h after feed withdrawal, respectively. The result indicated that birds were fasted for at least 24 h after feed withdrawal in order to ensure that no previous feed residues remained in the digestive tract of chicks. In a subsequent experiment, forty-eight 24-day-old male chicks were used to determine SMA in soybean meal. Chicks were fasted for 24 h and then fed mineral-free or soybean meal diet for 4 h, and excreta samples were collected until 24 or 48 h after feed withdrawal. The results showed that the extended excreta collection time of 48 h after feed withdrawal was adequate for estimating SMA. The standardized availability values of Ca, P, Cu, Mn or Zn in soybean meal were 51.14%, 50.22%, 36.28%, 30.79% or 49.66%, respectively. In experiment 3, a similar bioassay was conducted with forty-eight 36-day-old male chicks to measure SMA in the same soybean meal. The standardized availability values of P (51.59%), Cu (36.37%), Mn (31.94%) or Zn (43.37%) were similar (P > 0.12) to the results of experiment 2 except for Ca (41.49%), indicating that the age of birds had no effect on the standardized availabilities of P, Cu, Mn or Zn in soybean meal. The results from this study suggested that this simple and rapid procedure could be used to determine SMA in feedstuffs (e.g., soybean meal) for broiler chicks.     

Effect of Sodium Selenite and Vitamin E on the Renal Cortex in Rats: An Ultrastructure Study

This study examined the use of vitamin E to alleviate toxic effects of sodium selenite. Adult male albino rats (n = 50) was divided into five groups. Group 1 was control, Groups 2 and 4 were treated with sodium selenite (2 mg/kg) for 2 and 4 weeks, respectively, Groups 3 and 5 were treated with sodium selenite (2 mg/kg) and vitamin E (100 mg/kg) for 2 and 4 weeks, respectively. Renal tissues were studied using anti-BCL2 and examined ultrastructurally. Positive Bax immunoreactivity was detected after 2 and more positive after 4 weeks and nearly all groups improved with co-administration of vitamin E. Ultrastructural study revealed lesions in Bowman's capsule and proximal convoluted tubules. The submicroscopic study revealed damage and necrosis of cortical structures after 2 and 4 weeks, respectively. After 4 weeks, cellular changes were seen, such as vacuolation and moderate degeneration of cells, widening of the urinary space scattered through the cortex with loss of cellular details, formation of apical buds, degeneration, and cellular rupture. Present findings disclosed an ameliorative effect of adding vitamin E to sodium selenite-induced changes in cortical tissues. Clinically, it is advised to add vitamin E to avoid selenium overdose hazards.     

Effect of K+, its Counter Anion, and pH on Sodium Efflux from Barley Root Tips

Sodium efflux from ²²Na⁺-loaded root tips root tips of Hordeumvulgare L. was markedly increased by replacing 10mM Na₂SO₄ inthe washing solution by K₂SO₄ with the same electrical conductivity.This increase was inhibited by both an uncoupler and an inhibitorof oxidative phosphorylation but not by ouabain. Potassium ionsdid not enhance Na⁺ efflux in the presence of a rapidly absorbedcounter anion, such as Cl^–, instead of . Efflux of ²²Na⁺ could also be enhanced by a low pH in theabsence of K⁺; this was prevented by uncouplers, but not byan inhibitor of the mitochondrial ATPase. It seems that K⁺ indirectly enhances Na⁺ efflux. It is suggestedthat metabolic K⁺ uptake in excess of the counter anion resultsin a proton gradient across the plasmalemma (acid outside) inducingH⁺/Na⁺ antiport.     

The Effect of Calcium on the Uptake and Distribution of Sodium in Excised Barley Roots

The total uptake and relative distribution of Na⁺ along the root was investigated in excised barley roots (Hordeum vulgare L. cv. Union) of 6-day-old plants cultured on 0.25 mM CaSO₄. One technique involved cutting the roots at harvest time after different uptake periods into different segments each 2 cm long. These segments were ashed and sodium was measured by flame photometry. For each experiment two treatments were done, one containing calcium in the uptake solution and one without calcium. A second technique involved the measurement of sodium transport, using labelled ²²Na⁺ solution. Although no significant differences could be found between the calcium containing and the calciumless treatments at 24 h, there were clearcut differences for the first 6 to 8 h. The effect of calcium on the first stages of the sodium uptake was a large accumulation of sodium in the part close to the apex with a translocation close to nil; whereas the sodium taken up in the absence of calcium did not accumulate in such large amounts in the apex region but was immediately transported basipetally.     

Selenium and Mercury in Native and Introduced Fish Species of Patagonian Lakes,Argentina

A survey of mercury (Hg) and selenium (Se) contents was performed in fish collected from lakes located in two National Parks of the northern patagonian Andean range. Two native species, catfish (Diplomystes viedmensis) and creole perch (Percichthys trucha), and three introduced species, brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss), and brook trout (Salvelinus fontinalis), were caught from lakes Nahuel Huapi, Moreno, Traful, Espejo Chico, and Guillelmo belonging to Nahuel Huapi National Park and from lakes Futalaufquen and Rivadavia, Los Alerces National Park. In lake Moreno, fish diet items were analyzed and rainbow trout grown in a farm. Hg and Se were measured in muscle and liver tissues by instrumental neutron activation analysis. The average concentrations in muscle of Hg for all species, ages, and lakes are between 0.4 to 1.0 μg g⁻¹ dry weight (DW) with a few fish, mainly native, exceeding the United States Environmental Protection Agency health advisory for freshwater fish limited consumption, and from 0.8 to 1.5 μg g⁻¹ DW for Se. Average concentrations in liver of Hg in all species range from 0.4 to 0.9 μg g⁻¹ DW. Brown trout, the top predator in these lakes, showed the lowest average Hg burden in both tissues. Se concentrations in the liver of brown and rainbow trout, up to 279 μg g⁻¹ DW, are higher than those expected for nearly pristine lakes, exceeding 20 μg g⁻¹ DW, the threshold concentration associated with Se toxicity. These species show lower Hg contents in muscle, suggesting a possible detoxification of Hg by a Se-rich diet. Creole perch and velvet catfish livers have lower Se concentrations, with a narrower span of values (2.3 to 8.5 μg g⁻¹ and 3.3 to 5.5 μg g⁻¹ DW respectively).     

A Lethal Toxic Substance for Brewing Yeast in Wheat and Barley

It is shown that among various grains, wheat and barley contain in the endosperm a toxic substance to brewing yeast, and the substance is easily extracted with a dilute sulfuric acid solution. One unit of the toxicity is defined as the lowest amount of the extract which inhibits the yeast growth in 10 ml of wort medium. Two or more units of the toxicity not only inhibited the yeast growth, but also caused the death of yeast cells. Although the toxic effect was not observed when divalent metallic ions such as Ca²⁺, Zn²⁺ or Fe²⁺ were present at a concentration of 5 × l0^?3 mole or more, the toxicity could be recovered by the addition of ethylene-diamine-tetra-acetate (EDTA). Genetic relationships on the content of the toxicity in wheat and barley and sensitivity of yeast strains to the toxicity are also presented.