EFFECTS OF LASALOCID AND CATIONOMYCIN ON THE EVOLUTION OF CERTAIN PARAMETERS IN THE BLOOD-PLASMA OF SHEEP

Six adult sheep were fed at maintenance level, successively over three experimental periods, 1100 g of a roughage-rich diet without suppleme nt or containing 33 mg kg(-1) of lasalocid or cationomycin. The feed w as administered in eight equal meals daily, every three hours. Blood s amples were taken in each animal from the jugular vein at 10.00 hours, 16.00 and 22.00 hours, one hour after the animals were fed. The ionop hores did not affect the plasma concentrations of glucose, free fatty acids, total amino acids, insulin, acetate, Ca or Mg. They decreased P -hydroxy butyrate content (P < 0.05) and increased that of albumin (P < 0.05). Lasalocid alone significantly decreased uremia, but the signi ficant threshold was only reached at 16.00 hours (P < 0.01). With this exception, the two ionophores had similar effects. Samples taken in p eripheral blood appear to be too far from nutrient absorption sites to give a clear indication of the effects of these molecules on the prod ucts absorbed or metabolised in the digestive tract.