��:�����:�: ���f;��'::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: THE PIG AS MODEL . Maternal and Fetal Nutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Infant Nutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Carbohydrate and Lipid Metabolism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amino Acid Metabolism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vitamin and Mineral Nutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The pig as a model for human nutrition

Selenium in agriculture and the environment

Role of selenium in male reproduction—A review

Weanling rats were fed a basal diet or this diet plus 02, 10, 20 or 40 mg/kg selenium (Se) as either selenite or selenomethionine (SeM) Except at the 02 mg/kg Se level, Se accumulated in all tissues at higher levels when SeM was fed than when selenite was given, and the magnitude of difference became more pronounced with increasing levels of dietary Se This was particularly true for muscle and brain Se levels in whole blood, testes, kidney and lungs were not significantly different between rats fed 02 mg/kg Se as selenite or as SeM, but the Se levels in liver, muscle and brain were higher in rats fed SeM Although the tissue Se concentrations differed markedly, there were no differences in the glutathione peroxidase (GPX) activity in tissues of rats fed SeM rather than selenite The percentage of Se associated with GPX was lower in all tissues from rats fed SeM than in those from rats fed selenite These results indicate that the chemical forms of dietary Se can have a marked influence on biological responses, including bioavailability of dietary Se

Effects of various dietary levels of selenium as selenite or selenomethionine on tissue selenium levels and glutathione peroxidase activity in rats.

Deficiency of cobalt, copper, iron, iodine, manganese, selenium, or zinc can cause a reduction in production. Reduced production occurs most commonly when a deficiency corresponds to the phases of growth, reproduction, or lactation. Because of environmental, nutrient, disease, genetic, and drug interactions, deficiencies of single or multiple elements can occur even when the levels recommended by the National Research Council for these nutrients are being fed. Additionally, random supplementation of trace elements above National Research Council recommendations is not justified because of the negative interaction among nutrients and potential toxicosis. Evaluation of trace element status can be difficult because many disease states will alter blood analytes used to evaluate nutrient adequacy. Proper dietary and animal evaluation, as well as response to supplementation, are necessary before diagnosing a trace element deficiency.

A. W. Groce

Papers

Natural dietary selenium, α-tocopherol and effect on tissue selenium.

Selenium supplementation of naturally high selenium diets for swine.

Selenium supplementation of practical diets for growing-finishing swine.

Selenium requirements in corn-soy diets for growing-finishing swine.

Selenium balance in the pig as affected by selenium source and vitamin E.