The level of free amino acids in erythrocytes of different breeds of hen

[Effect of graded dietary protein rations on the amino acid content of crude protein in various parts of the gastrointestinal tract and blood fractions of laying hens]

Four groups of four colostomized laying hens each received rations only consisting of wheat, vitamins plus a mineral mixture and a graded daily feed supply of 110 g, 88 g, 66 g and 44 g. The determination of amino acids from faeces was carried out after hydrolysis from a 6-day sampling period from the 16 laying hybrids. At the end of the experiment the animals were slaughtered. The corpuscular fractions of the blood, the contents of crop and stomach as well as of the intestines were also hydrolysed and the amino acid content in the crude protein was determined. In addition, the content of free amino acids in the blood plasma was determined. The content of amino acids in the protein of the corpuscular blood fractions remained uninfluenced by the decreasing amino acid and energy supply. The content of free basic amino acids in the blood plasma decreased with the decreasing supply with amino acids and energy, whereas the content of free amino acids with branched chains and hydroxylized ones increased. The content of glutamic acid in the contents of crop and stomach changed considerably in comparison with feed protein. The amino acid values of the crude protein in the contents of the intestines and in faeces to a large extent differ considerably from those of the wheat fed and are approximate values of body protein. Deficient supply with amino acids and energy did not influence the apparent digestibility of the amino acids.