Academic literature on the topic 'Selenium Sheep Rats'

AbstractBoth selenium, as an effector and regulator of antioxidative enzymes activity, and thyroid hormones are potent immunomodulators. Besides, selenium incorporated into iodothyronine deiodinases is involved in the thyroid function and thus indirectly regulates the immune response. Studies of the mutual influence of selenium and thyroid hormones on the immune response are scarce, hence we analyzed the effects of an iodothyronine deiodinases blocker, propylthiouracil (PTU), and selenium deficiency on the function of peritoneal macrophages, and titer of naturally occurring anti-sheep red blood cells (SRBC) IgM antibodies in juvenile rats. The experiment was carried out on 64 Wistar male rats allotted to 4 groups: controlselenium adequate PTU-group; selenium adequate, PTU+ group; selenium defi cient, PTU-group; and selenium defi cient, PTU+. The selenium adequate and selenium defi cient groups were fed a diet containing 0.334 and 0.031 mg Se/kg, respectively. PTU+ groups received PTU (150 mg/L) in drinking water. After 3 weeks, thyroxine (T4), triiodothyronine (T3), and thyroid stimulating hormone (TSH) were determined. The animals having “intermediate” concentrations of T3(1.56-1.69 nmol/L) and T4(41-50 nmol/L) were excluded from further analysis. Thus, PTU+ groups included hypothyroid animals (T3≤1.55 nmol/L; T4≤40 nmol/L), while PTU-groups included euthyroid rats (T3≥1.70 nmol/L; T4≥50 nmol/L). Both groups of selenium deficient rats had, when compared to the control group, a significantly lower activity of glutathione peroxidase GPx1 and GPx3. Neither selenium deficiency nor PTU influenced the adherence of peritoneal macrophages. Selenium deficiency significantly decreased the peroxide synthesis in macrophages and significantly increased the titer of anti-SRBC IgM. Hypotyroidism alone or in combination with selenium deficiency had no influence on these parameters.

. Subterranean clover (Trifolium subterraneum) based pastures were fertilised with sodium selenite at 9 rates from 0 to 800 g Se/ha on 2 sites in 1983. In order to measure the residual value in 1984 and 1985, further applications of sodium selenite were superimposed on the original 9 treatments. Green pasture was sampled annually, dry pasture was sampled once, only in 1984 and the concentration of selenium in the pasture was measured. The sampled pasture was sorted into 2 components: subterranean clover, and non-subterranean clover. Except for the third site that had a quadratic response for the non-subterranean clover component of the pasture, the concentration of selenium in plants increased linearly with application rate. The selenium concentration in subterranean clover was lower than that in the other species in the pasture. Differences between years were large: in 1985, the concentration in plant material was twice that in 1983 and 1984. The dry summer feed had higher concentrations of selenium than the green pasture. The residual value of selenite was 25% in the first year and 15% in the second year. Adequate dietary levels of selenium for sheep would require an annual application of about 200 g sodium selenite/ha to these soils.

Fauna-free and faunated Canadian Arcott rams (21 and 23, respectively) were fed a corn silage diet supplemented with soybean meal for 110 d. Ruminal protozoa had no effect (P > 0.05) on plasma selenium concentrations but decreased the selenium concentration in the kidney cortex (P < 0.01), liver (P < 0.05), and spleen (P < 0.01). Key words: Sheep, selenium, Protozoa

Selenium (Se) is an essential trace mineral that when deficient, has been associated with increased disease evidence in sheep. Selenium deficient areas are widespread in UK and Ireland affecting, soils, forages and consequently livestock. Se supplementation of ewes throughout pregnancy has been reported to reduce peri-natal lamb mortality and improve lamb growth rates (Muñoz et al., 2005). The aim of this trial was to evaluate the effect of long term Se supplementation of adult ewes within a range of hill sheep systems.

The article presents data on the wool productivity of sheep of the kurdyuchny breed depending on feeding them non-extruded and extruded grain mixtures with additives of selenium-containing preparations.

Oxidative stress is one of the most important factors responsible for poor quality of semen, and it is defined as an imbalance between the formation of reactive oxygen species (ROS, including hydroxyl radicals, superoxide anions, and hydrogen peroxide) and antioxidant capacity of semen. Antioxidants act as a powerful defence system against ROS attack in sperm cells by decreasing oxidative stress and they improve semen quality, which could be useful in the management of male infertility. Magra is a dual-purpose (wool and meat) hardy sheep breed that originated in the eastern and southern parts of the Bikaner district of Rajasthan, India. The present study evaluated the effects of the administration of vitamin E with selenium or vitamin C on serum antioxidants, testosterone, and seminal quality of Magra rams. Twenty-one Magra rams, aged between 1.5 and 2.5 years, were randomly assigned to treatment at weekly intervals with administration of either 1mL of vitamin E (tocopherol, 50mg mL−1) and selenium (1.5mg sodium selenite; n=7; VES), 8mL of vitamin C (250mg mL−1 sodium ascorbate; n=7; VC), or 1mL of saline (n=7; control) subcutaneously for 5 consecutive weeks. After the fourth week, semen and blood were collected twice a week for 5 consecutive weeks and assayed for seminal quality parameters, serum testosterone, and serum antioxidants. Data obtained were analysed statistically using te SPSS software (version 25.0; IBM Corp.). Mean values were compared using Duncan’s multiple range test. The semen parameters sperm motility, sperm concentration, live sperm percentage, and% HOST (hypo-osmotic swelling test)-positive sperm were significantly elevated, whereas reaction time and percentage of abnormal sperm were lower in both the treated groups compared with controls (P&lt;0.05). Seminal pH declined significantly in the VES group (P&lt;0.05), whereas it was not different between the VC and control groups of rams (P&gt;0.05). Glutathione peroxidase, superoxide dismutase, and total antioxidant capacity concentrations were higher in serum and seminal plasma of treated rams (P&lt;0.05). Serum testosterone concentrations were significantly elevated in VES and VC groups (P&lt;0.05). We concluded that the administration of vitamin E and selenium or vitamin C improves the serum testosterone production and seminal quality of rams.

Oxidative stress is one of the most important factors responsible for poor quality of semen, and it is defined as an imbalance between the formation of reactive oxygen species (ROS, including hydroxyl radicals, superoxide anions, and hydrogen peroxide) and antioxidant capacity of semen. Antioxidants act as a powerful defence system against ROS attack in sperm cells by decreasing oxidative stress and they improve semen quality, which could be useful in the management of male infertility. Magra is a dual-purpose (wool and meat) hardy sheep breed that originated in the eastern and southern parts of the Bikaner district of Rajasthan, India. The present study evaluated the effects of the administration of vitamin E with selenium or vitamin C on serum antioxidants, testosterone, and seminal quality of Magra rams. Twenty-one Magra rams, aged between 1.5 and 2.5 years, were randomly assigned to treatment at weekly intervals with administration of either 1mL of vitamin E (tocopherol, 50mg mL−1) and selenium (1.5mg sodium selenite; n=7; VES), 8mL of vitamin C (250mg mL−1 sodium ascorbate; n=7; VC), or 1mL of saline (n=7; control) subcutaneously for 5 consecutive weeks. After the fourth week, semen and blood were collected twice a week for 5 consecutive weeks and assayed for seminal quality parameters, serum testosterone, and serum antioxidants. Data obtained were analysed statistically using te SPSS software (version 25.0; IBM Corp.). Mean values were compared using Duncan’s multiple range test. The semen parameters sperm motility, sperm concentration, live sperm percentage, and% HOST (hypo-osmotic swelling test)-positive sperm were significantly elevated, whereas reaction time and percentage of abnormal sperm were lower in both the treated groups compared with controls (P&lt;0.05). Seminal pH declined significantly in the VES group (P&lt;0.05), whereas it was not different between the VC and control groups of rams (P&gt;0.05). Glutathione peroxidase, superoxide dismutase, and total antioxidant capacity concentrations were higher in serum and seminal plasma of treated rams (P&lt;0.05). Serum testosterone concentrations were significantly elevated in VES and VC groups (P&lt;0.05). We concluded that the administration of vitamin E and selenium or vitamin C improves the serum testosterone production and seminal quality of rams.

Trace element deficiencies have been reported throughout the UK and are known to decrease the productivity and welfare of animals. Selenium deficiency is characterised by muscular myopathy, white muscle disease or stiff lamb disease. Subclinical deficiencies can also cause reduced growth rate and impaired immune function. In ruminant animals, cobalt is required for the synthesis of vitamin B12 and deficiency leads to Pine, characterised by emaciation, anaemia and listlessness. Trace element deficiencies can be due to either a single element or multiple elements. Situations occur particularly in sheep where cobalt and/or selenium are deficient but where copper supplementation can be toxic. To correct these deficiencies, a single long-lasting and effective treatment in the form of a soluble glass bolus has been designed to release cobalt and selenium. This new bolus is similar to the commercial Cosecure® bolus, which is a Co/Se/Cu soluble glass, in which zinc replaces the copper.

Two experiments on weaner production are reported. In experiment 1, the liveweight and wool production were measured in medium Peppin Merino sheep that grazed at 10.5 weanerstha 8 plots of a mixed Phalaris aquatica-subterranean clover pasture or 8 plots of annual pasture (Trifolium subterraneum cv. Woogenellup and volunteer annual grass species). This was repeated over 2 years using autumn-born sheep; 4 groups on each pasture type were offered no supplement, 2 groups a cereal supplement (340 goats), and 2 groups of supplement isoenergetic with the cereal group but having a high protein meal replace some of the cereal (250 g oats and 60 g protein). The feed supplement was offered over the summer (January-April). The sheep on 2 of the unsupplemented plots and 1 of the 2 plots receiving either a cereal or cereal + protein supplement were offered access to a composite mineral block formulated to meet the mineral requirements of sheep with the exception of cobalt and selenium. There were 16 sheep on each plot within each group of 16 weaners, 4 were given an intraruminal cobalt 'bullet', 4 were given 5 mg of selenium orally, 4 given cobalt plus selenium and 4 were untreated controls. Experiment 2 was in year 3 with spring-born weaners on the same plots. The mineral block treatment was discarded on the plots receiving supplement and the effect of supplementary feeding at the beginning of March was compared with feeding in early January; barley was also compared with oats and protein. The stocking rate was raised to 13.5 sheep/ha. There were no statistically significant differences in sheep liveweight due to pasture type in either of the years of experiment 1 or experiment 2. Supplementation with cereals or protein-fortified cereals resulted in a significantly ( P < 0.05) increased liveweight at the end of March (5.6 kg in year 1,2.4 kg in year 2 of experiment 1, and 2.5 kg in experiment 2), and wool production (0.49 kg clean wool in year 1 and 0.3 1 kg in year 2 in experiment 1, and 0.49 in experiment 2). There was a significant liveweight response on the perennial plots to selenium + cobalt in year 1 of experiment 1. All cobalt-treated sheep were heavier ( P < 0.001) in year 2. Neither selenium nor cobalt significantly affected liveweight in experiment 2. The proportion of Phalaris aquatica on the perennial pasture diminished from 18% to less than 9% by the end of year 2 in experiment 1. These results suggest that, if perennial pastures cannot be maintained, then their establishment in the south-west of Western Australia would not result in greater animal production than on annual pasture. Decisions on using supplements would be dependent upon feed and wool prices.

Fine wool Merino and Border Leicester x Merino ewes grazed improved pastures low in selenium (Se) for 4 years at 6.3 and 12.5 sheep/ha; half of the ewes were supplemented with Se given as an intra-ruminal pellet. Selenium status of the ewes was monitored from Se concentrations in whole blood and plasma, and wool production, fibre diameter and liveweight were recorded. The unsupplemented ewes showed no overt signs of Se insufficiency; Se status was consistently low; and Se supplementation increased wool production and fibre diameter. Selenium status was lower in unsupplemented ewes grazed at the higher stocking rate and in ewes supporting a lamb; it showed seasonal trends and was negatively correlated with rainfall. Selenium concentrations in whole blood but not in plasma were lower in Merino than in Border Leicester x Merino ewes. Data relating to reproductive performance and the productivity of the lambs are presented in accompanying reports.