Liquid hot water treatment of rice straw enhances anaerobic degradation and inhibits methane production during in vitro ruminal fermentation

摘要

Liquid hot water (LHW) treatment can be used todisrupt the fiber structure of rice straw. This in vitroruminal batch culture study investigated the effect ofLHW treatment on feed degradation, methane (CH_4)production, and microbial populations. Rice straw wastreated by LHW, and in vitro ruminal fermentationwas performed using an automatic system with 72 h ofincubation. Scanning electron microscopy showed thatLHW treatment disrupted the physical structure of ricestraw. Liquid hot water treatment decreased neutraldetergent fiber and hemicellulose contents of the ricestraw and increased neutral detergent solubles, watersolublecarbohydrates, and arabinose contents. Liquidhot water treatment increased dry matter degradationand volatile fatty acid concentration and decreased theacetate: propionate ratio, CH_4 production, hydrogenaccumulation, neutral detergent fiber degradation,and populations of protozoa, fungi, and cellulolyticbacteria. In summary, LHW treatment disrupted thecellulose-hemicellulose-lignin structure matrix of ricestraw, leading to increased substrate degradability anddecreased CH_4 production. Therefore, the LHW treatmentis a potential strategy to improve the nutritivevalue of forage such as rice straw and decrease the CH_4emissions in ruminants.