The Optimum Dietary Essential Amino Acid Pattern for Male Taiwan Country Chicks (Report‪)‬

INTRODUCTION Taiwan country chickens are famous for their flavor (Cheng et al., 2008) and contributed approximately 60% of the Taiwan broiler industry value in 2007 (Agricultural statistics yearbook, 2007). The chickens are divided into two types, red or black, according to their feather color and characterized by a single comb, blue shank and a rich breast. These birds are not taken to market until 13 wk of age. Most studies on the nutrition of Taiwan country chickens focused on requirements for protein, metabolizable energy, calcium and phosphorous (Fan and Lee, 1984; Yu and Hsu, 1989; Yu et al., 1990; Shih et al., 1993; Huang et al., 2007) or on the effect of dietary inclusion of dehydrated food waste products on the growth performance (Chen et al., 2007). Only a handful of literature has concentrated upon the requirement for individual amino acids, including lysine (Hsu and Lin, 1990), methionine (Hsu and Lin, 1989) and tryptophan (Lin and Hsu, 1994; Chen and Hsu, 1996). Establishing the optimum pattern of dietary essential amino acids will be an approach to attain the requirements (g/kg diet) of all essential amino acids for Taiwan country chickens because they would be computed by means of multiplying the optimum pattern by the requirement for a single essential amino acid resulting from dose-response trials. Wang and Fuller (1989) extended a method, published by Bender (1965) with rats, based on the removal of non-limiting amino acids with no effect on nitrogen retention. They set up the optimum dietary amino acid pattern for growing pigs. This method could not distinguish the requirements for maintenance and tissue protein accretion. Therefore, Fuller et al. (1989) designed consecutive trials to measure, simultaneously, requirements for maintenance and for body protein accretion for pigs. In addition, numerous literature reported on the accretion and maintenance requirements for individual essential amino acids for chicks (Baker, 1991; Burnham and Gous, 1992; Baker et al., 1996; Edwards et al., 1997; Kim et al., 1997a, b, c; Edwards and Baker, 1999; Edwards et al., 1999; Sklan and Noy, 2005). After modifying the previous studies done on swine or chicks, a series of experiments were conducted to establish the optimum dietary essential amino acid pattern for red feather type male Taiwan country chicks to compute the requirements for individual essential amino acids and simultaneously set up requirements for maintenance and for growth.