THE LYSINE REQUIREMENT OF THE WEANLING PIG

Osborne and Mendel in 1914 showed that lysine was essential for the growth of the young white rat. In addition lysine has been proved to be essential for the adult dog (Rose and Rice, 1939), the young mouse (Bauer and Berg, 1943), and adult men (Rose, 1947). Mertz et al. 1949 demonstrated that lysine was essential for the growth and development of the weanling pig. Brinegar et al. 1950 reported the L-lysine requirement of the weanling pig to be 0.6% when fed a ration containing 10.6% protein, and 1.2% when fed a ration containing about 22% protein. These values correspond to 5.7 and 5.5% of the dietary protein in the 10.6 and 22% protein rations, respectively. Shelton et al. 1951, using a ration which contained 10% gelatin, found the lysine requirement of the weanling pig to be 4.2% of the ration protein. Becker et al. 1954, using the approach of Harte and Travers (1947) and Mitchell (1950) to estimate amino acid requirements, reported that the lysine requirement of the pig from 5 to 9 weeks of age did not exceed 0.72% when fed a 12 % milk protein diet. Pfander and Tribble (1955) were unable to get an improvement in growth when they added supplementary lysine to 18, 16 and 14% protein rations which contained 0.85, 0.72 and 0.60% lysine, respectively. Similarly, Meade (1956) obtained no improvement in N retention when he supplemented with L-lysine a 15.9% protein diet containing 0.69% lysine. Evidence presented by Grau (1948) and Almquist (1949)