Gruhn K, Richter G, Raue B
Arch Tierernahr. 1977 Feb;27(2):135-44. doi: 10.1080/17450397709424564.
4 experimental hens were fed labelled casein as sole protein source for a period of 6 days. The dietary nitrogen contained a 15N excess of 0.69 atom%. Hens 1 and 2 were slaughtered 2 days and hens 3 and 4 four days after receiving the last 15N' dose. 10 follicles with diameters more than 6 mm were investigated for their content of N, for the TCE-soluble portion of N (TCE=trichloracetic acid) and for the content of different amino acids in protein. The corresponding 15N' data were established and the same analyses were carried out with the residual ovaries. The mean proportion of the TCE soluble N fraction in the total amount of N was 90% in the follicles and 88% in the residual ovaries. The content of certain kinds of amino acids in follicular protein depends on the degree of maturity of the follicles. There were differences in the percentage composition of amino acids between the follicles and residual ovaries. The mean percentage of lysine contained in follicular protein was 7,2%, that in the residual ovaries 7,9%. Corresponding data for arginine were 6,9% and 7,9%, those for glutamic acid 11,5% and 13,8%, for glycine 3,1% and 5,7%, for alanine 5,0% and 6,1%, for methionine 2,8% and 1,7% and for cystine 3,7% and 2,4%. Less than half of the 15N' atom % and less than half of the percentage of 15N' in the total amount of N and of the amount of amino acids in both the follicles and the residual ovaries were found in the hens killed 144 hrs after the last 15N dose than in the hens slaughtered 48 hrs after the last 15N intake. The atom % of 15N' in the N contained in the amino acids serine, threonine, glutamic acid, proline and leucine decreased with the process of ageing of the follicles. On an average, 88% of the total quantity of 15N' contained in the follicle samples were found as amino acid N, while in the residual ovaries 90% were found.
