EFFECT OF A DIETARY LYSINE DEFICIENCY ON THE CONCENTRATION OF AMINO ACIDS IN THE DEPROTEINIZED BLOOD PLASMA OF CHICKS

Abstract

A lysine-deficient basal diet, both with and without supplemental lysine added, was fed to groups of Barred Plymouth Rock cockerels from hatching to 4 weeks of age. At this time blood samples were taken from the carotid artery and pooled for each group. Twelve amino acids were determined in the deproteinized plasma by microbiological assay. Deproteinized plasma from birds receiving the lysine-deficient diet was lower in lysine content and higher in threonine and tyrosine than that from birds fed the lysine-supplemented diet. Other amino acids showed much smaller differences. A similar amino acid pattern was observed when the birds were fed the lysine-supplemented diet for 25 days from hatching and then the lysine-deficient diet for 3 days before blood samples were taken. Withholding feed for 24 hours before the samples were taken resulted in a marked increase in lysine and threonine concentration, an effect which has been reported by other workers. Acid hydrolysis of the deproteinized plasma increased somewhat the concentration of lysine, as measured microbiologically, but had no effect on, or somewhat reduced, the concentrations of other amino acids.