EFFECT OF DIETARY ANTIBIOTICS ON PROTEIN AND ENERGY-METABOLISM IN RATS - POSSIBLE SIGNIFICANCE OF THE GUT MICROFLORA

The influence of the intestinal microbial activity on protein metabolism was tested in rats with three diets fed without and with antibiotics (Nebacitin). True protein digestibility, biological value, net protein utilisation, true amino acid digestibility and apparent digestible energy were measured. The intestinal microbial activity was on average reduced to one‐fifth by antibiotics. On a diet low in crude fibre (2.5%) but high in crude protein (17.6%), this reduction had only a minor influence on the parameters for protein quality that were measured. However, true digestibilities of histidine and cystine were strongly reduced by the antibiotic treatment. The digestibility of energy was also significantly reduced (5%). For diets higher in crude fibre and lower in protein, the influence of the microbial activity was more pronounced. Digestibility of protein and energy were severely reduced by the dietary antibiotic treatment. In general, antibiotic supplementation decreased the parameters that were measured. Copyright © 1979 John Wiley & Sons, Ltd