Effect of different fiber and energy source on rumen activity and in situ organic matter and fiber degradation.

摘要

Three Mediterranean buffaloes (average weight 450+-45 kg), were sequentially fed on high-fibre (HF1 and HF2) and low-fibre (LF1 and LF2) diets to evaluate the effects of concentrate and fibre source on the main fermentation parameters in the rumen. In situ lucerne and wheat straw organic matter, NDF and ADF degradation were measured. Average total volatile fatty acid concentration increased by 49 and 31% when buffaloes were fed on LF1 and LF2 diets compared with the HF1 diet (control); with lower rumen liquor pH, the maize silage-based diet (LF1) had a more constant fermentation activity throughout the sampling period. The high starch content and starch to neutral carbon sugar (NSC) ratio of the LF diet resulted in higher trichloroacetic acid (TCA)-precipitable protein compared with other diets, indicating more intense microbial protein synthesis. LF1 was 87% higher than the other diets with 473.35 mg/100 ml of TCA-precipitable protein measured in the first 3 h after a meal. The results show the importance of an adequate NSC/CP ratio to increase microbial protein synthesis and to reduce ammonia released in the rumen because of energy deficiency. The rumen environment selected when feeding different diets did not affect organic matter, NDF and ADFof in situ degradation of lucerne and wheat straw.