Studies on unidentified growth factors

Abstract

I . Chicks at 10 d of age were given diets containing all the nutrients known to be required, with L-amino acids in place of protein. Dietary supplements were added isonitrogenously.2. O x liver (100 g/kg) greatly improved the chicks' growth rate, whereas torula yeast (50 g/kg) was inactive. The activity of fresh moist liver was considered to be due largely to an organic factor, because of the inactivity of water and the low activity of liver ash.3. The growth rates of chicks receiving diets based upon casein and isolated soya-bean protein were significantly improved by the inclusion of IOO g fresh ox liver/kg, but not of 5 0 g torula yeast/kg. 4 . These results show that chicks receiving an amino acid diet require an organic growth factor (Progressin) that differs from the yeast factor required by rats receiving an amino acid diet.

Common beans (<i>Phaseolus vulgaris L.</i>) in the rations for cattle in feedlot

“…Ammonia concentrations showed average of 9.52 mg/dL. The concentration of NH 3 -N ruminal of 5 mg/dL to support cellulolytic activity is recommender to [35], already [36], pointed out that for maximum microbial growth the minimum would be 10 mg/dL, next the values found in this work.…”