FAECAL URIC ACID AS AN INDICATOR IN DETERMINATION OF FOOD UTILIZATION

The impracticability or impossibility of quantitatively separating uneaten food and faeces is the major obstacle to the measurement of the consumption and utilization of food by the grain-feeding insects frequently used in nutritional studies. This difficulty can be overcome by using faecal uric acid as an indicator for the indirect determination of the proportions of uneaten food and faeces in a mixture. A small sample of faeces is separated and analysed for uric acid. The remaining mixture is homogenized and an aliquot is analysed for uric acid. Since the food contains no uric acid the weight of faeces present can be calculated by dividing the total weight of uric acid in the mixture by the weight of uric acid per weight of faeces. In a comparison the uric acid method gave results almost identical with those obtained by the painstaking manual separation of food and faeces. © 1969.