5National Research Council.Nutrient requirements of poultry[M].9th edition.Washington DC:National Academy Press,1994.
6Botsoglou N, Florou-Paneri P, Botsoglou E, et al. The effect of feeding rosemary,oregano,saffron and a-to- copheryl acetate on hen performance and oxidative stability of eggs[J]. South African Journal of Ani real Science,2005,35(3) :143-151.
7Stadelman M J, Pratt D E. Factors influencing compo- sition of the hen' s egg[J]. World ' s Poult Sci J, 1989,45 : 247-266.
8Mabe I, Rapp C, Bain M M, et al. Supplementation of a corn-soybean meal diet with manganese, copper, and zinc from organic or inorganic sources improves egg- shell quality in aged laying hens[J]. Poult Sci, 2003, 82(12) : 1903-1913.