The role of essential trace elements in porcine fetal development

The hypothesis for these studies is that maternal consumption of trace elements during gestation is necessary for fetal and neonatal development. In experiment 1, pregnant females were fed diets supplemented with proteinated zinc (Zn), copper (Cu), and manganese (Mn) and fetal and maternal tissue was collected during early pregnancy. Females fed the proteinated trace elements had improved conception rate, more live fetuses and fewer dead fetuses than females fed trace elements as inorganic salt. Concentrations of Zn, Cu, and Mn were increased in fetal tissue of females fed the proteinated trace element supplement. In experiment 2, the effect of selenium (Se) on fetal development was investigated. Pregnant gilts were fed gestation diets low (0.05 ppm) or adequate (0.39 ppm) in Se and fetuses were collected throughout gestation. The content of Se in the whole fetus was not affected by maternal Se intake, but fetal liver Se was reduced in fetuses from gilts fed the low Se diet. When pregnant sows were fed the low Se diet, maternal and fetal liver had elevated concentrations of hydrogen peroxide and malondialdehyde indicating reduced antioxidant capacity. The nucleotide sequence of the genes coding for the selenium-dependant, antioxidant enzymes cellular glutathione peroxidase and thioredoxin reductase were determined in d 13 embryos. These nucleotide sequences have significant homologies with published sequences from the pig, cow, and human. In experiment 3, humoral response was determined in neonates of females fed gestation and lactation diets either adequate or low in Se. Pigs born to and suckled by females fed the adequate Se diet had elevated serum immunoglobulin isotype M compared to pigs born to and suckled by females fed low Se diets. These results indicate that the fetus relies on the maternal system for adequate supply of trace minerals needed for normal development. When females are fed gestation diets that do not meet nutritional demands, the effect can be observed in the fetus as well as the neonate.