Influence of Source and Level of Dietary Protein on Plasma Free Amino Acid Concentrations in Growing Swine

TYPPO et al. (1970) and Nordstrom et al. (1970) reported that concentrations of plasma free amino acids at various intervals post-feeding were quite sensitive to the dietary supply of amino acids. Other workers (Richardson, Blaylock and Lyman, 1953; Olsen et al., 1959; Puchal et al., 1962) also indicated that plasma free amino acid concentrations tended to reflect dietary amino acid levels. This experiment was conducted to investigate the sensitivity of concentrations of selected free amino acids in the plasma to the dietary supply as influenced by source as well as level of dietary protein. Also, comparison of free amino acid levels in the plasma of pigs fed different protein sources providing similar dietary supplies of amino acids should provide information relative to availability of individual amino acids from the various proteins. Experimental Procedure Thirty-six Yorkshire barrows averaging 20.7 kg initially were housed in individual pens equipped with slatted wooden floors and providing 0.54 m2 of floor space.