Study On Ultrasonic Treatment Of Ammoniated Or Alkalized Rice Straw To Increase Rumen Degradation Rate

The purpose of this experiment was to study the effects of ultrasonic treatment on the content of ammoniated and alkalized rice straw fiber,rumen degradation characteristics,and carbohydrate molecular structure.In this experiment,a response surface design was used to build a four-factor five-level central combination design model with ultrasonic power,ultrasonic time,liquid-solid ratio,and ultrasonic power density in the container.The content of neutral detergent fiber(NDF),acid detergent fiber(ADF)and acid detergent lignin(ADL)was used to establish a multiple quadratic regression mathematical model for the response value to obtain the best ultrasonic process parameters and compare them with the actual measured values to verify the reliability of the model.Simultaneously determine the nutritional value and rumen degradation parameters of ammoniated and alkalized rice straw before and after the process parameter treatment.The nutritional value and the rumen degradation parameters of ammoniated and alkalized rice straw straw were analyzed by Fourier Infrared Spectroscopy(FTIR)to analyze the changes in carbohydrate molecular structure,and then to study their correlation.The research results are as follows:Experiment 1:Optimizing the ultrasonic process parameters of ammoniated and alkalized rice straw using response surface test designThe response surface analysis method can effectively predict the contents of ADL(R~2=0.71)and ADF(R~2=0.88)of ultrasonically treated ammoniated rice straw.Significant analysis shows that ultrasonic power has a higher influence on the contents of ADL and ADF.Using the response surface to optimize the ultrasonic parameters of each model,the best ultrasonic conditions for ammoniated rice straw were obtained:ultrasonic power 112 W,ultrasonic time 17.3 min,liquid-solid ratio 10.7:1,acoustic power density in the container 1.317 W/ml;response surface The analysis method can effectively predict the content of ADL(R~2=0.75)and ADF(R~2=0.84)of alkalized rice straw by ultrasonic treatment.Significance analysis shows that the sound power density in the container has a high degree of influence on the content of ADL and ADF.The response parameters were used to optimize the ultrasonic parameters of each model,and the best ultrasonic conditions for the alkalized rice straw were 90 W,14.1 min,14.4:1 liquid-solid ratio,and 1.716 W/ml in the container.Under the best ultrasonic process parameters obtained by the response surface fitting,the predicted values of ADL and ADF contents of ammoniated rice straw are 7.95%and 43.75%,and the actual values are 7.40%and 42.59%,respectively;the alkalized rice straw ADL and The predicted values of ADF content are 5.95%and 40.95%,and the actual values are 6.57%and 38.32%,respectively.The actual results are close to the model predictions.Experiment 2:Effect of ultrasonic treatment on nutrient composition and rumen degradation characteristics of ammoniated and alkalized rice strawAccording to the analysis of nutrients,ultrasonic treatment can significantly reduce the content of ADL and ADF on the basis of ammoniation(P<0.05),and significantly reduce the content of ADL and ADF on the basis of alkalization(P<0.01),But it has little effect on the content of NDF.The ammoniated rice straw ADL content decreased by 11.37%,ADF content decreased by 6.64%;alkalized rice straw ADL content decreased by 25.85%,ADF content decreased by 14.46%.In the rumen degradation experiment,the slow degradation part(b),potential degradation part(d)and effective degradation rate(ED)of ammoniated and alkalized rice straw DM,NDF,ADF after ultrasonic treatment were significantly improved(P<0.01),the effective degradation rate of ammoniated rice straw DM,NDF and ADF increased by 38.84%,24.98%and 24.00%respectively,and the effective degradation rate of alkalized rice straw dry matter(DM),NDF and ADF increased by 7.15%,10.88%,9.55%respectively.Experiment 3:Analysis of changes in carbohydrate molecular structure using Fourier transform infrared spectroscopy(FTIR)There are differences between the molecular structure of carbohydrates in ammoniated and alkalized rice straw before and after sonication.The peak area of fiber composite(A?CELC)and total carbohydrate peak area(A?CHO)and the ratio(A?CELC/A?STCHO)before and after ultrasound were significantly different(P<0.05).Moreover,A?CELC,A?CHO and A?CELC/A?STCHO can effectively estimate the content of ADF(R~2=0.73)and ADL(R~2=0.80),DM effective degradation rate(R~2=0.71),NDF effective degradation rate(R~2=0.71)and ADF effective degradation rate(R~2=0.70).In summary,proper ultrasonic treatment can reduce the content of ADF and ADL in ammoniated and alkalized rice straw,increase its effective degradation rate.