[Nonessential amino acid content in early weaned piglets following qualitatively and quantitively different protein...

A total of 60 piglets of German Landrace weaned at the age of 2 weeks were fed ad libitum with isoenergetic diets of different proteins (casein + dried skim milk, soybean protein + dried skim milk, only soybean protein) and different protein levels in the diet (20, 27, 34, 40% in D.M.). After 4 weeks the piglets were homogenized and examined for their content of non essential amino acids in the whole body mass by ion exchange chromatography. On the fresh and dried material the content of the non essential amino acids Asx, Ser, Glx, Pro, Gly and Ala increased with the higher protein contents of the diet. Decreasing protein quality reduced the content of serine, whereas coincidently the concentration of glycine, especially on the protein levels of 20 and 27% in the diet increased. On the contrary the protein quality had no effect on the concentration of Asx, Glx, Pro and Ala. Related to the whole body protein the highest contents of the non essential amino acids, excepting serine, were found in piglets which got few protein of low quality. Influenced by the different protein supply the proportion of glycine to lysine varied from 1.28 to 2.17. The mentioned changes in the amino acid composition of the piglets are mainly discussed as shiftings in the proportion of organs and tissues and their protein composition.