1. Nutrient Requirements of Poultry;National Research Council,1994
2. “Cys” is the approved abbreviation for cysteine, but since there is no abbreviation for cystine, this manuscript will use the abbreviation “Cys” for cystine.
3. Nutrient Requirements of Poultry;National Research Council,1971
4. Nutrient Requirements of Poultry;National Research Council,1977
5. Nutrient Requirements of Poultry;National Research Council,1984