The effect of dietary selenium and vitamin A on biochemical parameters and survival of young among white-tailed deer (Odocoileus virginianus)

The effect of long-acting injectable selenium formulations on blood and liver selenium concentrations and liveweights of red deer (Cervus elaphus)

AIM

To evaluate the efficacy of a new long acting injectable selenium ( Se ) formulation to increase the Se status and prevent Se deficiency in red deer.

METHODS

Groups of weaned red deer (four stags and six hinds/group) grazing pastures containing <30 mg Se/kg DM were injected subcutaneously with either 0.5, 1.0 or 2.0 mg Se/kg as a new formulation of BaSeO4 (Deposel Multidose), 1.0mgSe/kg of a current formulation (Deposel), or not treated. Blood Se concentrations and liveweight were measured nine times at intervals over 377 and 270 days, respectively.

RESULTS

Both formulations of Se elevated blood Se concentrations from 105 nmol/l pre-injection for at least 377 days with peak levels of 1894, 1395 and 818 nmol/l for high, medium and low doses of Deposel Multidose, respectively, at 73141 days, and 1508 nmol/l at 73-141 days for the medium dose of Deposel, which persisted at similar levels for the duration of the study. Deposel Multidose produced fewer and less severe subcutaneous tissue reactions than Deposel. Pastures contained 10 to 30 mg Se/kg DM. There was no significant difference in growth rate between treated and control deer. There was a significant (p<0. 01) linear relationship (y = 1.25x + 71.6, R2=0.86) between blood (x) and liver (y) Se concentrations in the range of 120 - 2100 nmol/l for blood concentrations, and 200 - 3000 nmol/kg for liver concentrations.

CONCLUSION

Injections of BaSeO4 in both formulations studied were effective in increasing the Se status of deer but the new formulation produced fewer and less-severe tissue reactions. Young growing red deer appear less sensitive to Se deficiency as measured by weight gain, than sheep and cattle, suggesting that reference ranges for those species are not appropriate for deer. There was a linear correlation between blood and liver selenium concentrations.

Relationships between vitamin E status and erythrocyte stability in sheep

Stability of erythrocytes from sheep with vitamin E deficiency (E-deficient) was compared by two haemolytic tests, one based on osmotic fragility in hypotonic saline and the other on detergent sensitivity in Tween 20. Relationships between haemolysis, plasma alpha-tocopherol concentration and creatine kinase (CK) activity were evaluated. E-deficient animals were clinically healthy but had elevated (greater than 1000 iu per 1) CK activities and low (less than 1 mumol per 1) alpha-tocopherol concentrations compared with control sheep (less than 500 iu per 1 and greater than 1.5 mumol per 1, respectively). Erythrocytes from E-deficient sheep were markedly more susceptible to detergent treatment than those from controls, but osmotic fragility was similar in both groups. Detergent sensitivity was directly related to plasma alpha-tocopherol concentration and CK activity but not to erythrocyte glutathione peroxidase activity. Within 24 h of supplementation (300 mg alpha-tocopherol subcutaneously) of E-deficient sheep, plasma alpha-tocopherol concentrations were increased, CK activities decreased and erythrocyte susceptibility to detergent-induced haemolysis was significantly reduced. Concentrations of alpha-tocopherol returned rapidly (less than 3 days) to pre-supplement values, although decreased haemolytic responses persisted longer (greater than 7 days). Cells from E-deficient animals were protected against detergent-induced haemolysis by preincubation with alpha-tocopherol in vitro. The results indicate that detergent sensitivity of erythrocytes may provide the basis of a simple functional test for vitamin E deficiency in sheep.

Effect of diet on blood selenium and glutathione peroxidase activity in the alligator

Four groups of immature alligators were fed diets of ground nutria (Myocastor coypus) meat; ground fish (Merluccius spp); nutria plus sodium selenite; and fish plus sodium selenite. Plasma selenium, plasma glutathione peroxidase and erythrocyte glutathione peroxidase (GSH-Px) were measured in blood samples taken 10 days before and at 18, 39 and 60 days after initiating the diets. Selenium concentration and plasma GSH-Px activity remained at low levels in the group fed nutria alone, but increased significantly in the groups fed fish alone, nutria plus selenite and fish plus selenite. Plasma selenium and GSH-Px activity showed a high degree of correlation (r = 0.944). Erythrocyte GSH-Px activity was more variable than the plasma enzyme activity, but increased significantly in the groups fed nutria plus selenite and fish plus selenite by 39 days. In the groups fed fish alone enzyme activity was significantly higher than the group fed nutria alone only at 60 days.