超声改善氨化稻秸纤维结构工艺优化及其对瘤胃降解特性的影响

试验旨在研究超声改善氨化稻秸纤维结构工艺优化及其对瘤胃降解特性的影响。采用响应面设计优化氨化稻秸纤维的超声水平，以中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）和酸性洗涤木质素（ADL）含量为响应值建立多元二次回归数学模型，得到最佳超声水平，并测定最佳超声水平下氨化稻秸与未处理氨化稻秸中营养成分的含量。利用尼龙袋法测定上述样品在奶牛瘤胃中干物质（DM）、NDF及ADF的降解率，得到各营养成分的动态降解参数。结果显示，氨化稻秸的最佳超声水平为超声功率112 W，超声时间17.3 min，液固比10.7：1，容器内声功率密度1.317 W/mL，在此超声水平下的氨化稻秸ADF和ADL含量的最小值分别为43.75%、7.95%，显著低于超声前（P<0.05），实际结果与模型预测接近，说明该模型可行。与超声前相比，氨化稻秸ADF降低了6.64%，ADL降低了11.38%。在瘤胃降解试验中，超声处理后的氨化稻秸DM、NDF、ADF的慢速降解部分（b）、潜在降解部分（d）和有效降解率（ED）均得到极显著提高（P<0.01），其中DM、NDF和ADF的慢速降解部分分别提高了36.52%、30.06%和22.19%，潜在降解部分分别提高了27.15%、28.56%和21.35%，有效降解率分别提高了25.09%、24.98%和24.00%。综上所述，适宜的超声处理可以降低氨化稻秸中ADF和ADL的含量，提高有效降解率。

The Optimization of Ultrasonic to Improve the Fiber Structure of Ammoniated Rice Straw and Its Effect on Rumen Degradation Characteristics

The objective of this study was to investigate the optimization of ultrasonic to improve the fiber structure of ammoniated rice straw and its effect on rumen degradation characteristics.The response surface analysis of four factors and five levels of central composite was used to design and optimize the ammoniated rice straw fiber modified ultrasonic conditions.Based on the neutral detergent fiber (NDF),acid detergent fiber (ADF) and acid detergent lignin (ADL) content as response values,a multivariate quadratic regression mathematical model was established to obtain the best ultrasound level.The contents of nutrients in ammoniated rice straw under the optimal ultrasonic level and untreated ammoniated rice straw were determined.The degradation rates of dry matter (DM),NDF and ADF in the rumen of cows were determined by nylon bag method,and the dynamic degradation parameters of each nutrient component were obtained.The results showed that ultrasonic power was 112 W,ultrasonic time was 17.3 min,liquid-solid ratio was 10.7 to 1,and ultrasonic power density was 1.317 W/mL,which was the best ultrasonic condition for ammoniating straw.At this ultrasonic level,the minimum contents of ADF and ADL of ammoniated rice straw were 43.75% and 7.95%,respectively,which were significantly lower than those before ultrasonic (P<0.05).The actual results were close to the model prediction,indicating that the model was feasible.Compared with before ultrasound,ammoniated rice straw ADF decreased by 6.64% and ADL decreased by 11.38%.After ultrasonic treatment,the slow degradation part (b),potential degradation part (d) and effective degradation rate (ED) of DM,NDF,ADF of the ammoniated rice straw were significantly improved (P<0.01),the slow degradation parts of which increased by 36.52%,30.06% and 22.19%,respectively,the potential degradation parts increased by 27.15%,28.56% and 21.35%,respectively,and the effective degradation rates increased by 25.09%,24.98% and 24.00%,respectively.In conclusion,appropriate ultrasonic treatment could reduce the content of ADF and ADL in the ammoniated rice straw and improve the effective degradation rate.