The inter-relationships of individual proteins and carbohydrates during fermentation in the rumen of the sheep. II. The fermentation of starch in the presence of proteins and other substances containing nitrogen

Abstract

1. The inter-relationships of starch and proteins during fermentation in the rumen are measured by estimating volatile fatty acids, ammonia, lactic acid and amino acids after administering the starch and protein supplements alone or together.2. The presence of casein stimulates the formation of volatile fatty acids from starch. Simpler nitrogen-containing compounds are less effective than casein; other proteins are as effective as casein provided they are fermented as rapidly in the rumen.3. Proteins can be divided roughly into three groups on the basis of the rapidity with which they give rise to ammonia in the rumen: casein, gelatin, ground nut protein > soy protein, wheat gluten > bovine albumin, zein.4. The proportion of acetic acid falls and of propionic acid and higher acids rises as proteins that are rapidly fermented are placed in the rumen.