Protein and Amino Acid Requirements of the Guinea Pig II. Effect of Age, Potassium and Magnesium and Type of Protein

Abstract

The requirements for supplementary arginine and methionine by young male guinea pigs receiving a 24% caseinsucrose diet have been shown to exist throughout the period of rapid growth. The need for supplementary arginine and methionine decreased as the animals matured, the decrease approximately following the decrease in growth rate. Satisfactory growth responses to amino acids were obtained only when supplementary potassium and magnesium were provided in the diet. Because of the decreased need for arginine by the older animals, there were only slight differences in the growth rate when 6% of gelatin was substituted for an equivalent amount of casein and when the casein was entirely replaced with a soybean protein.