2Brandao N J, Stefan V, Mendoea B B, et ah The essen- tial role of zinc in growth [J]. Nutr. Rev., 1995 (15): 335.
3Peters J C, Mahan D C. Effects of dietary organic and inorganic trace mineral levels on sow reproductive per- formances and daily mineral intakes over six parities [J ]. Journal of Animal Science,2008 (86) :2247 - 2260.
4Payne R L, Bidner T D, Fakler T M, et al. Growth and intestinal morphology of pigs from sows fed two zinc sources during gestation and lactation [J]. Jour- nal of Animal Science,2006(84) :2141 -2149.
5Ward J D, Spears L W, Kegley E B. Bioavailability of copper proteinateand copper carbonate relative to copper sulfate in cattle [J]. Dairy Sci., 1996 (79): 127 - 132.
6Hoover S L, Clson M S, Hill G M. Evaluation of ex- cret ion and retention of zinc from inor ganic and oranic sources in diets fed to weaning pigs[J]. Jour- nal of Animal Science, 1997,75 (1) : 189.
5Kin-ya Ashida,Tohru Matsui,Jiro Itoh,Hideo Yano,Takashi Nakajima. Zinc distribution in the small-intestinal digesta of pigs fed skim milk powder or defatted soybean flour[J] 2000,Biological Trace Element Research(1):31~40