The effect of the growth-promoting, appetite-stimulating or “physin” factor on the live-weight increase of swine

Abstract

Attention has been drawn to the remarkable growth rates obtained in certain litters of pigs under farm conditions.It has been pointed out that no explanation has been put forward to account for their occurrence.The literature relating to the new dietary factor, physin (Mapson), essential for optimum growth and reproduction in experimental rats, trout and dogs, has been reviewed.Experiments are reported in which rations, adequate as far as our present knowledge of essential dietary constituents goes, were fed to young growing swine. In each of three experiments, animals which received in addition 4 oz. of raw minced liver per day showed a 40 per cent. increase in growth rate compared with the controls.When food intake was controlled according to the new method of individual feeding, the liver animals showed the same gains in weight as the animals receiving the basal diet alone.