Effect of grazing pasture with a low selenium content on the concentrations of triiodothyronine and thyroxine in serum, and GSH-Px activity in erythrocytes in cows in Chile

Relationship Between Selenium, Copper, Zinc and Their Biomarkers in Blood and Skeletal Muscle Tissue in Adult Horses From Southern Chile

Microminerals are necessary for all bodily functions. In animal species, selenium (Se), copper (Cu) and zinc (Zn) all form part of antioxidant enzymes. Micromineral deficiencies, particularly Se, are well recognized in large animal species in Chile. Glutathion peroxidase (GPx) is a widely used biomarker for Se nutritional status and to diagnose Se deficiency in horses. Superoxide dismutase (SOD) is a Cu and Zn-dependant antioxidant enzyme, although it is not commonly used as a proxy for the nutritional status of these minerals. Ceruloplasmin (CP) is used as a biomarker of Cu nutritional status. This study´s objective was to explore correlation between said minerals and biomarkers in adult horses from southern Chile. Se, Cu, Zn, GPx, SOD, and CP were measured in whole blood of a group of 32 adult horses (5-15 years old). Further, a second group of 14 adult horses (5-15 years old) underwent gluteal muscle biopsies to determine Cu, Zn, GPx, and SOD. Correlations were determined by means of Pearson´s r coefficient. Significant correlations were found for blood GPx and Se (r = 0.79), blood GPx and SOD (r = -0.6), muscular GPx and SOD (r = 0.78), and Cu and CP (r = 0.48). These results confirm previously described strong association between blood GPx and Se in horses, validating the former´s use as a diagnostic proxy of Se deficiency in Chilean horses, and suggest significant interactions between GPx and SOD in blood and muscle tissue.

Potential benefits of selenium supplementation in patients with kidney disease

Trace element deficiency is common among patients with end-stage renal disease (ESRD); the reason is that since these patients undergo dialysis, they lose these elements more than healthy people, and also the use of trace elements is restricted due to loss of appetite. Selenium (Se) is a trace element that is essential for the oxidative stress defense system. Se deficiency leads to some complications similar to those often seen in ESRD patients, such as all-cause mortality due to cardiovascular diseases, bone loss, uric acid elevation, and anemia. This article aims to review the evidence on consequences of Se deficiency in ESRD patients, as well as effects of Se supplementation in hemodialysis patients. Multiple databases were searched to summarize the available evidence on selenium's role in kidney diseases. Since the complications of ESRD and those of Se deficiency are mostly similar, this triggers the idea that Se deficiency may be considered as a cause of these problems, but it needs to be more assessed that Se deficiency is a single factor or there are other factors participated in. Also the role of Se supplementation on resolving the mentioned complications, needs to be more studied through welldesigned clinical studies.

Studies of Selenium Deficiency in the Wumeng Semi-Fine Wool Sheep

Wumeng semi-fine wool sheep are affected by a disease, characterized by emaciation, stiffness and trembling of the limbs, weakness and inability to stand, and sudden death. The objective of the study was to determine possible relationships between the disease and mineral deficiencies. Samples of wool, blood, and liver were collected from affected and healthy sheep. Samples of soil and forage were collected from affected and unaffected areas. The samples were used for hematological and biochemical analyses and mineral nutrient measurements. Results showed that selenium concentrations in forage and soil samples from affected areas were significantly lower than those from unaffected areas (P < 0.01). Meanwhile, selenium concentrations of wool, blood, and liver from the affected sheep were also significantly lower than those from the healthy sheep (P < 0.01). The mean concentration of hemoglobin (Hb), packed cell volume (PCV), and mean corpuscular hemoglobin (MCH) from the affected sheep were significantly lower than those from the healthy sheep (P < 0.01). Serum glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activity in the affected sheep were significantly lower than those in the healthy sheep (P < 0.01). Serum creatine phosphokinase (CPK), lactate dehydrogenase (LDH), glutamate pyruvate transaminase (GPT), glutamic oxaloacetic transaminase (GOT), alkaline phosphatase (ALP), and malondialdehyde (MDA) values in the affected sheep were significantly higher than those in the healthy sheep (P < 0.01). Serum concentrations of free triiodothyronine (FT₃) and triiodothyronine (TT₃) in the affected sheep were significantly lower than those in the healthy sheep; serum concentrations of free tetraiodothyronine (FT₄) and tetraiodothyronine (TT₄) in the affected sheep were significantly higher than those in the healthy sheep (P < 0.01). But the administration of selenium and vitamin E by hypodermic injection prevented and cured the disease. The injection contains 0.1% and 5% of sodium selenite and vitamin E, respectively. A single dose is 6, 6, and 2 mL for mature ewe, mature ram, and lamb, respectively, repeated only once 15 days later. This study demonstrated that the disorder of Wumeng semi-fine wool sheep was mainly caused by the selenium deficiency in soil and forage.

Uterine Inertia due to Severe Selenium Deficiency in a Parturient Mare

A 12-year-old, multiparous, parturient show jumper embryo-recipient mare presented at a veterinary hospital, seven days past her due date and with a dilated cervix, for evaluation of mild colic. Gastrointestinal or metabolic abnormalities and fetal maldispositions were excluded as causes of dystocia, and a diagnosis of uterine inertia was made. There was no uterine response to oxytocin treatment. A live filly was delivered via C-section, and severe selenium deficiency was eventually confirmed in the mare, her offspring, and in the herd of origin. The filly was born with severe white muscle disease and required intensive treatment. This report suggests that selenium deficiency is an underlying cause of equine uterine inertia in the absence of other causes of dystocia.

Osteopathology and selenium deficiency co-occurring in a population of endangered Patagonian huemul (Hippocamelus bisulcus)

Background

About 1,000 endangered Patagonian huemul deer (Hippocamelus bisulcus) remain in Chile and 350–500 in Argentina. Most groups (>100) are not recovering, and prevalence of osteopathology in Argentina was at least 57%. Here I describe relevant cases of osteopathology from a Chilean population which, however, recently also provided data on trace mineral status, supporting the initial hypothesis that nutrition may be a primary etiologic factor. Additionally, recent data on bone chemical composition of Argentine cases and soil analyses are discussed.

Results

Fluoride levels in Argentine cases with osteopathology were low and fluorosis was discarded as an etiological factor. Selenium deficiency occurred in 73% of huemul from the Chilean population which exhibited several cases with osteopathology. The pathophysiognomy included extensive erosion; tooth loss; porosification; perforations of palate, maxillar and mandibular bone with frequent exposure of tooth roots; and fractured mandibula. Areas currently used by remaining huemul have mainly acidic volcanic soils, which reduces selenium bioavailability: mean soil selenium levels from areas typically used by extant huemul were very deficient (0.19 ppm), corroborating documented overt selenium deficiency in local livestock and plants. The area of extant huemul is known to result in primary iodine deficiency in livestock which is aggravated by selenium deficiency.

Conclusions

Currently the most parsimonious explanation for frequent osteopathology and lack of numerical recovery are the combined effects of selenium and iodine deficiencies based on: osteopathology in a population of selenium deficient huemul; selenium deficient livestock, plants and soils; acidic soils; and regional primary iodine deficiency. The nexus between mineral nutrition and population dynamics of huemul may be due to constraints on their movements to fertile lowlands, including the elimination of historic migratory traditions, and concomitant elimination of source populations.

[Behavior of antioxidant parameters in young cattle during the course of the year]

OBJECTIVE

To analyze the behavior of antioxidant parameters in young cattle over 1 year and to detect possible health-related deficits during certain periods.

MATERIALS AND METHODS

Every 2 months over the course of 1 year, six healthy 12-month-old Holstein Friesian/German black and white heifers underwent a clinical examination and blood samples were obtained. The 36 animals were kept in tie-stalls during September, November, January, March and July, and solely at pasture in May. The antioxidant parameters superoxide dismutase (SOD), glutathione peroxidase (GPX) and the Trolox equivalent antioxidant capacity (TEAC), hematocrit and the metabolic parameters β-hydroxybutyrate, bilirubin, cholesterol, protein, albumin, urea, haptoglobin, calcium, inorganic phosphate, iron, alkaline phosphatase, aspartate transaminase, glutamate dehydrogenase and creatine kinase were determined.

RESULTS

The GPX activities in September and January were significantly lower than those from March till July. The TEAC concentrations were in particular lower in January and significantly lower in March than in September and November. Differing SOD activities were not statistically significant. The correlation between SOD and GPX during the entire period was significant as well as between SOD and TEAC throughout the year except in January, whereas GPX and the TEAC only significantly correlated in November and from March till July. Albumin significantly correlated with the TEAC. The metabolic parameters were within the physiological range at all times, except urea in November and July and phosphate in May.

CONCLUSION

The young cattle showed significantly reduced GPX activities from September to January, and reduced TEAC concentrations particularly in January and March. Decreased GPX activity is indicative of a low selenium supply. Among other disadvantages, this is unfavorable for the development of heifers. A reduced provision with antioxidant agents, particularly vitamin E and β-carotene, is indicated by the TEAC and has negative effects that are comparable to those caused by a lack of selenium. In terms of health prophylaxis, particularly during winter, specific attention should be given to the supply of sufficient trace elements and good quality silage.

Selenium concentration and glutathione peroxidase (GSH-Px) activity in serum of cows at different stages of lactation

The aim of the study was to evaluate the activity of glutathione peroxidase (GSH-Px) and the concentration of selenium in Holstein-Friesian cows at different stages of lactation. Selenium was determined spectrofluorimetrically and GSH-Px activity using a Sigma CGP1 Glutathione Peroxidase Cellular Activity Assay kit. Mean serum selenium concentration was highest in early-lactation multiparous cows (0.18 μg/ml) and the lowest in dry cows (0.111 μg/ml). In early lactation, serum selenium concentration was significantly (P ≤ 0.01) higher in multiparous cows than in cows from the other groups. Mean GSH-Px activity in the serum of dry cows was over twice lower than in late-lactation cows (P ≤ 0.01) and over four times lower than in first-calving heifers and multiparous cows in early lactation (P ≤ 0.01). The coefficients of Spearman's rank correlation between GSH-Px activity and selenium concentration in the cows at different stages of lactation were not significant. A significant (P ≤ 0.01) mean positive correlation (0.46) was found between GSH-Px activity and serum selenium concentration for all the cows analysed together. The highest Se concentration and GSH-Px activity found in the serum of cows during the first stage of lactation may suggest that the generation of reactive oxygen species and their derivatives was higher during this period compared to the other stages, thus placing the cows at a greater risk of oxidative stress. It is therefore essential to give particular attention during this period to meeting the cows' requirement for selenium and other feed components that increase, directly or indirectly, the capacity of the body's antioxidant system.

Somatic cell count in milk of selenium-supplemented dairy cows after an intramammary challenge with Staphylococcus aureus

The objective of this study was to evaluate the effect of selenium (Se) supplementation on milk somatic cell count (SCC) in dairy cows. Twelve multiparous Holstein-Friesian cows were fed a diet containing a suboptimal Se concentration (<0.05 ppm, dry basis) starting 2 months before calving. Supplemented cows (n=6) received a single s.c. injection of barium selenate (1 ml/50 kg BW) 45 days prior to calving, whereas control group was kept unsupplemented. Twenty weeks after calving, two mammary quarters (right side) of each cow were challenged with 205,000 cfu/ml of Staphylococcus aureus (strain Newbould 305). Blood was collected bi-weekly until day 150 of lactation for the analysis of blood glutathione peroxidase (GPx1; EC 1.11.1.9) activity. To re-isolate the challenging pathogen and to evaluate SCC, aseptic milk samples were collected daily starting on the day of challenge, and finishing 7 days after inoculation. Unsupplemented cows had a lower activity of GPx1 through the experiment (P<0.001). Natural log SCC (lnSCC) was higher in unsupplemented than Se-supplemented cows (P=0.04), showing evidence of significance after 5 days. Selenium supplementation of dairy cows fed a diet containing a suboptimal Se concentration, resulted in higher blood activity of GPx1, and lower mean lnSCC after an intramammary challenge with Staph. aureus.