Are most natural sources of selenium readily available?
A. There are few data available with animals but some recent work with humans suggest that bioavailability may vary. Research from Norway compared availabilities of selenium in fish and wheat. Platelet selenium increased 30% for those people eating the wheat products but decreased 11% for those consuming a similar amount of selenium in fish. The reason for apparent differences in availability are not clear. Q. Can the zinc requirement of pigs be affected by the supplemental protein source. A. Yes. Recent British research has shown that as the level of canola meal in the diet increased there was a decrease in the amount of zinc absorbed. The authors believed that the high phytate content of the canola meal was the cause of the reduced zinc absorption by the pigs. Q. Can high iron intakes of grazing animals cause a mineral imbalance. A. It is unlikely. Recent research at North Carolina showed that feeding sheep as high as 1,200 mg iron/kg diet did not affect zinc status. Zinc is thought
