Glucose urea amino acids in the blood of ewes during pregnancy and lactation effect of nutritional state during late pregnancy

Grizard, J.; Tissier, M.; Champredon, C.; Prugnaud, J.; Pion, R.

Annales de Biologie Animale Biochimie Biophysique 19(1A): 55-72


ISSN/ISBN: 0003-388X
Accession: 005528318

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A factorial experiment using 28 Limousine ewes was carried out to study protein metabolism during pregnancy and lactation. The experimental treatments included 2 levels of energy intake during 7 wk prepartum (high:H; low:B) and 2 states of body reserves at 8 wk prepartum (fat:G; lean:M). The animals bore or were suckling either twins (D) or singles (S). Preprandial and postprandial jugular blood samples were taken at 38, 24 and 10 days prepartum and at 5, 13, 26 and 40 days postpartum. Blood glucose, urea and free amino acids were recorded. During pregnancy, reducing dietary energy supply resulted in a large decrease of lamb birthweight (-0.8 kg) and a diminution of the levels of glucose, some non-essential (alanine, citrulline) and some essential (tyrosine, phenylalanine, threonine, valine, leucine) free amino acids in the blood of ewes; blood urea increased. Reducing body reserves caused a small drop in lamb birthweight (-0.3 kg) and an increment of glucose and free methionine in the blood. During the last 2 wk of pregnancy, postprandial blood glucose level rose. During the first 2 wk of lactation, the amino acid requirements for milk protein synthesis were higher than amino acid supply by the digestive tract. At 1 wk postpartum, ewes showed very high blood levels of most of the essential free amino acids, free proline and free glycine. Some of the essential free amino acids (valine, leucine, phenylalanine, lysine, histidine) then decreased. Reducing body reserves resulted in an increment of most of the essential free amino acids in the blood. Blood levels of some of these amino acids seemed to be related to blood free methionine. Reducing the energy supply of the diet during late pregnancy increased blood glucose.