Increase in metabolic rate of the alligator fed proteins or amino acids

Energy required for protein digestion, amino acid absorption and transport, and for protein synthesis in the alligator was estimated by determining oxygen consumption following feeding of single amino acids, various amino acid mixtures, fish, casein, gelatin, zein, and a gelatin hydrolysate. Results suggested a low energy requirement for protein digestion, for absorption of the released amino acids, and for amino acid transport, and a high energy requirement for protein synthesis. Little energy was needed for absorption and transport of neutral single amino acids but absorption of single ionic amino acids appeared to require energy. The alligator's metabolic rate is so low that processes requiring extra energy increased oxygen consumption as much as 300%. Peptide bond synthesis seems to have been responsible for the 3-fold increase in metabolic rate after feeding protein. Whether that phenomenon should be called "specific dynamic action" is problematical.