INFLUENCE OF SOME FOOD-ADDITIVES ON IGG PLASMA-CONCENTRATIONS IN NEWBORN CALVES FED AN IMMUNOGLOBULIN SOLUTION EXTRACTED FROM COLOSTRUM

A lot of newborn ruminants have no free access to their mother's colos trum, due to various reasons. For them, colostro-replacers are now on the market. These products contain immunoglobulins but their capacity to pass through the intestinal wall is often doubtful. So, an experime nt has been designed to test the influence of three supplements on the absorption of immunoglobulins extracted from colostrum by ultrafiltra tion. Fifty newborn calves were divided into five groups of ten. The f irst group received three meals of colostrum, exactly 2, 10, and 18 h after birth. According to the same kinetics, the four other groups rec eived the same amount of immunoglobulins but previously extracted from colostrum and diluted in a saline solution. The diets given to the la st three groups were supplemented with isobutyric acid, caseino-macrop eptide and colostrum extract, respectively. Immunoglobulins extracted from colostrum were badly absorbed compared with control colostrum die t. In spite of liberal supply of immunoglobulins given soon after birt h, the IgG plasmatic levels of the carves fed immunoglobulin solution remained below what is usually admitted as a good passive immunity. Al l the three additives were unable to improve the immunoglobulins' abso rption.