Métabolisme protéique de l'agneau nouveau-né. — I. Conséquences de l'ingestion de colostrum sur la glycémie, la gammaglobulinémie et les teneurs en acides aminés libres des tissus

Abstract

Ten newborn lambs were divided into two groups at birth. Five of them were fed hourly with cow colostrum; the others (unfed lambs) were given saline. Jugular blood levels of glucose, urea, free amino acids and IgG1 were measured during the 10-hour period following birth. The lambs were then exsanguinated under pentobarbital anaesthesia. Free amino acid levels were determined in liver, muscle (longissimus dorsi) and skin. The glycogen contents of the liver and whole body were measured. The IgG1 levels were determined in the intestinal wall and in the contents of the abomasum and small intestine. The blood glucose levels increased after birth in both groups and did not differ significantly in either group. After colostrum feeding, hepatic glycogen and blood urea concentrations were higher in fed than in unfed lambs. Blood free essential amino acid levels which increased after birth in the fed group, were higher in that group than in the unfed one. Nonessential free amino acid levels remained nearly constant throughout the experimental period and did not differ significantly in either group (fig. 2). Free threonine and valine in the liver, skin and muscle were higher in the colostrum-fed lambs than in the others. IgG1 levels increased after birth in the blood of the fed lambs and seemed to be closely related to the intestinal contents of these compounds (fig. 3). The amount of blood free essential amino acids provided by the hydrolysis of colostral proteins was estimated at about 43% of the amount entering the small intestine.