The in Vitro Synthesis of a Chick Growth Promoting Factor in Hen Feces

Rubin, Bird, and Rothchild (1946) reported that hen feces contained a factor essential for maximum growth of chicks fed a cereal grain-soybean oil meal diet containing adequate amounts of the known growth factors. The discussion in the paper by Rubin et al. (1946) indicates that these workers believed the chick growth factor was synthesized in the intestinal tract of the hen. However, it was pointed out that the possibility of synthesis after voiding of the feces could not be ruled out. Since no description of the manner of collecting the feces or the time and temperature of holding before drying was given in the paper by Rubin et al. (1946) it was considered desirable for us to determine whether fecal material reduced to temperatures too low for bacterial growth immediately after voiding would contain chick growth promoting properties. Feces were collected from White Leghorn hens kept in an unheated house . . .