Methionine Deficiency Under Ad Libitum and Force-Feeding Conditions

Abstract

The effects of methionine deficiency on weight, nitrogen intake, and nitrogen balance have been observed employing both ad libitum and force-feeding procedures. Under the conditions of this experiment there was a tendency for the weights of the animals receiving the ration ad libitum to differ from those of the group receiving the ration by a force-feeding procedure. This can probably be attributed to differences in the amounts of ration consumed. Since the nitrogen balance curves and the nitrogen intake curves followed almost exactly the same trends, it appears that fluctuations in the nitrogen balance curves were due to the amount of ration consumed. This is substantiated by the fact that a fairly constant daily excretion of nitrogen was observed; therefore, variations in nitrogen intake will cause fluctuations in the nitrogen balance curves. Comparing the results of our studies with those of other workers, it appears that the level of nitrogen in the ration, as well as the actual amount of food consumed, must be considered when observing the effects of an amino acid deficiency on nitrogen retention.