20 

 compared to the oxide or sulfate forms. A 75% inorganic and 

 25% proteinate Zn, Mn and Cu mixture provided as a dietary 

 supplement improved embryo and/or fetal survival, and reduced 

 the duration of estrus in sows compared to those supplemented 

 with an organic mixture (Mirando et al . , 1993) . 



Spears (1991) showed, feeding a Mn deficient diet to 

 heifers, how Mn methionine (MnMet) supplementation was 

 superior to MnO in improving growth and feed efficiency. 

 Henry et al . (1992) suggested MnMet to be equally available to 

 MnS0 4 but more available than MnO. The relative 

 bioavailability of Mn proteinate was similar to that of MnS0 4 

 in chicks fed diets either devoid of or containing fiber and 

 phytate (Baker and Halpin, 1987) . Also in chicks, MnMet was 

 174% more available (based on bone Mn accumulation) than MnO 

 (Fly et al., 1989), and in another study (Henry et al . , 1989) 

 MnMet was not only more available than MnO but also than 

 MnS0 4 . 



Organic iodine (ethylenediamine dihydroiodide) 

 supplemented mice had similar macrophage phagocytosis to NaI0 3 

 and Nal supplemented mice (Siddiqui et al . , 1993) . 



In a toxicity and tissue retention study conducted with 

 rats, Na 2 Se0 4 was found to be more toxic to methionine 

 deficient rats than L-selenomethionine (SeMet) (Salbe and 

 Levander, 1990) . For pigs, however, SeMet was more toxic than 

 the inorganic form (Herigstad et al . , 1973) . Furthermore, 

 SeMet has been shown to protect chicks against pancreatic 



