Effects Of Additives On Fermentation Quality Of Rice Straw Silage

In recent years, with the development of livestock industry, the shortage of feedstuffs has become a limiting factor for the sustainable development of livestock industry in China. Rice straw is an important straw resource, and its annual production amounts to 192 million tons in China. But just a small proportion is utilized as roughage because of its low content of crude protein (CP), high content of crude fibre (CF), low dry matter digestibility and poor palatability. Therefore, it is important to find out a safe and effective method for the use of rice straw. Studies in Japan and Korea showed that rice straw ensiling could improve its feeding value. But it seemed difficult to succeed due to its low epiphytic lactic acid bacteria (LAB) and water soluble carbohydrates (WSC). It is necessary to use silage additives to improve the fermentation quality of rice straw. But just few studies on rice straw silage in China are available.This study investigated the improvement of LAB, cellulase, glucose and microorganism on the fermentation quality on the basis of the selection of rice varieties. It aimed to find out a practical method for rice straw ensiling and to further develop rice straw resource.There was significant difference in WSC content in straw among rice varieties. The fermentation quality of rice straw silage had a significant correlation to the WSC content in fresh straw. Jinlingxiang, Wuyujing3 and Hang1 had high content of WSC in straw and thus good fermentation quality, whereas IRAT109 and Dular had low WSC in straw with bad fermentation quality.The application of LAB, glucose, cellulase could, to a certain extent, improve the fermentation quality of rice straw silage, in which pH value, acetic acid(AA), butyric acid(BA), and ammonia nitrogen(NH₃-N) decreased and lactic acid(LA) increased. Meanwhile, the application also improved feeding value of rice straw, with the increase of CP content and in vitro organic matter digestibility(IVOMD), the decline of neutral detergent fibre(NDF)and acid detergent fibre(ADF). The order of effectiveness of the treatments was LAB+glucose>LAB+cellucase>LAB>cellucase.The treatment of LAB had a better effect than that of microorganism on the fermentation qulaity and feeding value of rice straw silage.Therefore, to obtain good fermentation quality silage, we should choose the rice varieties that contained high content of WSC in the rice straw, ensiled after harvest in time with LAB, or some sugar-rich materials additionally.