3Jan Van den Broecke,L-threonine:new opportunities in diet formulation,Feed Mix, 1994(4):21-23.
4Webel DM,et al.Digestible threonine requirement of broiler chickens during the period three to six and six to eight weeks post hatching,Poultry Science,1996 (10):1 253-1 257.
5Watanable R, et al.Effects of dietary threonine levels on the tissue amino acid concentration and threonine metabolic enzyme activity in laying hens,Animal Science and Tecknology,1997(6):529-536.