Comparative Study On Nutritional Evaluation Of Roughages By Gas Production Technique And CNCPS

To explore the comparative study on nutritional evaluation by gas production technique and CNCPS,seven kinds of roughages(silage corn straw,alfalfa,corn straw,bean straw,chinensis,rice straw,specific silage corn straw) were selected.This investigation included that nutritional ingredient of roughages were studied by CNCPS,nutritional value of roughages were evaluated by the correlated data of gas production and volatility fatty acid(VFA),and the correlation between gas production,volatility fatty acid and nutritional ingredient were established.The new thought and theoretical evidence were provided by estimating nutritional ingredient of roughage by gas production technique in vitro.The results of the experiment showed that:(1) the content of CP was in a high difference between different roughages,the content of soluble protein was relatively more in alfalfa,the content of PC in corn straw silage,the ADIP which could not be degradated were low.The PB1, PB2 and PC between specific silage corn straw and corn straw were significant differences,these confirmed that protein composition was different between different species.High quality roughages (such as alfalfa) compared with low quality roughages(such as corn straw),NDF(%DM), ADF(%DM),slow-degradated protein PB3 and non-degradated carbohydrate CC were lower, CP(%DM) and fast-degradated carbohydrate CA were higher than others(P＜0.05).The non-used cell wall of bean straw had a higher level(P＜0.05).(2) Negative correlations between cumulative gas productions at 12,24,36,72h(P＜0.05) and 48h(P＜0.01) and CP were observed,but positive correlations between gas production at 12,24,36,48,72h(P＜0.01) and NDS/CP,and between gas production at 12h(P＜0.05),24,36,48,72h(P＜0.01) and(NDS-ASH)/CP were found.Positive correlations between parameters of a,b,a+b and c and NDS/CP(P＜0.01) were found,and a,b,a+b (P＜0.01) and c(P＜0.05) positive correlated with(NDS-ASH)/CP,and negative correlations between b,a+b and c and CP(P＜0.05) were also found.Positive correlation between degradation rate of NDF(P＜0.01) and ADF(P＜0.05) and CP were observed,but negative correlation between degradation rate of NDF(P＜0.05) and ADF(P＜0.01) and items of NDS/CP and(NDS-ASH)/CP was gotten.Regression model between gas production and CNCPS component was established with R~2＞0.973,which indicated that the model had practical value.(3) the total quantity of VFA was different significantly(P＜0.05) between alfalfa and chinensis,silage corn straw and specific silage corn straw when they were culturated for 36h.The degradation rate of ADF,NDF of alfalfa were the highest.Regression model between propionate quantity and nutrient content calculating by CNCPS was established,and propionate quantity estimation error was smaller,it indicated that there was a corresponding relation between propionate quantity and nutrient content calculating by CNCPS.(4)TVFA=1.07×GAS-1.41×CP-0.90×NDF-6.80×NDS/CP-2.33×(NDS-ASH)/CP+113.70, R~2=0.7431.The value of R~2 was bigger than other's results,which indicated that it had more practical value.To sum up,nutritional ingredient content by CNCPS of different roughages could be estimated by regression model between cumulated gas production at different times and ingredient,so more experimental time and expenditure could be saved.