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

Thirty-two adult female white-tailed deer were assigned to four complete pelleted diets (+/- 45 ppm vitamin E; +/- 0.2 ppm selenium). Selenium and vitamin E concentration in the unsupplemented diet was 0.04 and 5.5 ppm, respectively. Biochemical parameters of the erythrocyte (RBC) glutathione peroxidase system and survival of off-spring to weaning were followed for 2 years. At the end of the second year, 12 male young (3 per treatment) and the remaining adults were killed, and liver and muscle parameters of the glutathione system determined. Plasma selenium (Se) and vitamin E (E) were significantly lower among unsupplemented adults within 6 months of treatment and remained essentially constant from 10 months on. In vitro hemolysis and mortality of young were affected by dietary E but not by Se. Tissue glutathione peroxidase (GSH-Px) was correlated with tissue Se in all tissues measured (RBC, liver and muscle). Tissue Se, in turn, was related to dietary Se. Thus, dietary Se deficiency (Se = 0.04 ppm) resulted in biochemical deficiency (depressed GSH-Px). This was not reflected in gross lesions among the adults, nor in increased mortality among young.

Interrelationships of erythrocyte glutathione peroxidase system enzymes in the fasted Beagle

Eight adult female Beagles were fasted for 21 days to investigate responses of the erythrocyte glutathione peroxidase system enzymes. Blood samples were collected once a week. Erythrocyte reduced glutathione was maintained within 10% of base-line value. Hexose monophosphate pathway dehydrogenases showed a significant inverse relationship to glutathione reductase (GR) activity. Further, active GR, as a percentage of total GR, increased as hexose monophosphate pathway dehydrogenase activity fell. A similar relationship between these enzymes has been reported in human glucose-6-phosphate dehydrogenase deficiency. Also, glutathione peroxidase showed an inverse linear response to erythrocytic reduced glutathione. Though the responses of this system are complex, they appear interrelated.

Influence of Salinity on Protein Requirements of Rainbow Trout (Salmo gairdneri) Fingerlings

Rainbow trout (Salmo gairdneri) juveniles maintained at 10 and 20 ppt salinity were fed seven diet treatments from 30 to 60% protein in 5% increments for 10 weeks. The fish were stocked in cones, initially 50 fish per cone. Biweekly weights of diets and fish were determined and mortality was recorded daily. Percentage weight gain, gross diet efficiency, and protein efficiency ratio (P.E.R.) were computed. The minimum protein levels required for fish to achieve highest performance using these criteria were 40 and 45% for those maintained at 10 and 20 ppt, respectively. Mortality was significantly (P < 0.05) higher for fish maintained at the higher salinity. Analyses of the fish carcasses were conducted at the beginning and end of the experiment on representative samples to estimate the grams protein retained and apparent net protein utilization (N.P.U.) to verify the above findings. All the available data showed that dietary protein was of major consequence on all measurements until the minimum required level of protein in the diet was reached, while salinity was of minor consequence. P.E.R. and apparent N.P.U. were 2.10 and 34.4, respectively, for casein diets at the 40% protein level.