[Study of the interrelationships of amprolium-thiamine, Coccidia and coccidiosis in chicks].

A total of 180 birds, divided into 9 groups of 20 each, were used in tests to elucidate the prophylactic value of the coccidiostatic drug Amprolium in the suggested dose of 125 g per ton feed, and given at the rate of a four-fold high dose (500 g/ton), with and without additional amounts of thiamine incorporated into the standard mixtures. It was found that Amprolium could hardly suppress to a full extent the excretion of oocysts in doses which were as high as 500 g/ton. When using additional amounts of thiamine such effect could not be produced. It is believed that thiamine contributes to the lowering of the activity of the preparation as well as to be prolongation of the parasite development in the intestine and the increase in the asexual populations and oocyst excretion by 66 per cent. In cases where poultry farms are infected despite the use of Amprolium it is suggested to make it clear with objectivity to what extent coccidiosis is due to the resistance phenomenon or the lowering in the activity of the preparation as a result of the higher concentration of thiamine in the feed mixture, and to effect the respective correction so as to reach an optimal ration of the components.