Effects of graded concentrations of supplemental selenium on selenium concentrations in tissues and prediction equations for estimating dietary selenium intake in pigs

The experiment was conducted to determine the effects of graded dietary selenium (Se) on organ weight and Se concentrations in tissues and to develop equations for estimating dietary Se intake in pigs. Sixteen barrows (initial body weight = 30.0 ± 2.6) were allotted to four dietary treatments including graded Se supplementations with 0, 1, 5, and 50 mg/kg of diet. The experimental diets fed to the pigs for 30 d, and then the pigs were euthanized, and the organs, muscle, and urine samples were collected. The hair and blood samples of pigs were collected on d 15 and 30. Equations were developed for predicting daily Se intake using the Se concentration in plasma, hair, liver, kidneys, muscle, or urine. For graded dietary Se concentrations, linear and quadratic effects on the final body weight, weight and relative weight of liver and kidneys were not observed. The Se concentration in plasma, hair, liver, kidneys, muscle, and urine were linearly and quadratically increased as dietary Se concentration increased (P < 0.001). The dietary Se concentration was positively correlated with the Se concentrations in the plasma, organs, muscle, and urine (r > 0.81, P < 0.001). The equations for estimating dietary Se intake using the Se concentration in the plasma, hair, or organ as an independent variable were significant (P < 0.05). In conclusion, the dietary Se concentration was well reflected in the Se concentration in the plasma, hair, liver, kidneys, and urine. The Se concentration in the plasma, hair, liver, and kidneys can be used as an independent variable for estimating the Se intake.