| This experiment was conducted to compare nutrients composition and ruminal fermentation characteristics of different types distillers' grains using cornell net carbohydrate and protein system(CNCPS)and in vitro gas production.The correlation analyses between CNCPS components and ruminal fermentation characteristics were carried out and the corresponding regression equations were established.Trial 1.Study on the nutrients composition of different types distillers' grains(1)Twenty four distillers' grains were sampled and divided into 5 categories,including 8 Luzhou-sorghum distillers' grains,4 Maotai-sorghum distillers' grains,4 highland barley distillers' grains,3 corn distillers' grain ands,5 barley brewers' grains.The nutrients components of different types distillers' grains were significantly different(P<0.05).Barley brewers' grains had the highst content of CP(P<0.05),and Luzhou-sorghum distillers' grains was the lowest(P<0.05).Barley brewers' grains and Maotai-sorghum distillers' grains had the highst level of NDIP(P<0.05).The content of ADIP in sorghum distillers' grains was significantly higher than the others(P<0.05).Highland barley distillers' grains had higher SCP and NPN(P<0.05).The CF,NDF,ADFand ADL contents in Luzhou-sorghum distillers' grains were significantly higher than the others(P<0.05),and the lowest content was corn distillers' grains(P<0.05).Corn distillers'grains had the highst level of NFE(P<0.05).Starch content in corn distillers' grains was significantly higher than the others(P<0.05),and barley brewers' grains was the lowest(P<0.05).(2)The proportions of CNCPS components in different types distillers' grains were different(P<0.05).The proportion of CA in barley brewers' grains was significantly higher than the others(P<0.05).Corn distillers' grains had the highst level of CB1(P<0.05).CC proportion of Luzhou-sorghum distillers' grains was significantly higher than the others(P<0.05),and corn distillers' grains the lowest(P<0.05).The proportion of PB3 in barley brewers' grains was significantly higher than the others(P<0.05),and Luzhou-sorghum distillers' grain was the lowest(P<0.05).The PC proportion of Luzhou-sorghum distillers'grains was significantly higher than the others(P<0.05).(3)The contents of mineral elements and anti-nutritional factors in different types distillers' grains were also different(P<0.05).The levels of Fe and Mn in sorghum distillers' grains were higher than the others(P<0.05),and the corn distillers' grains was the lowest(P<0.05).The contents of Cu and Zn in barley brewers' grains were significantly higher than the others(P<0.05).The level of tannin in sorghum distillers' grains was higher than the others(P<0.05),and the barley brewers' grains was the lowest(P<0.05).Si level of Luzhou-sorghum distillers' grains was significantly higher than the others(P<0.05),and the content of Si of Maotai-sorghum distillers' grains,highland barley distillers' grains,barley brewers' grains and corn distillers' grains decreased successively(P<0.05).Trial 2.Study on the in vitro ruminal fermentation characteristics of different types distillers' grains(1)With the extension of the fermentation time,the total gas production and potential gas production(a+b)of corn distillers' grains and highland barley distillers' grains were significantly higher than the others(P<0.05).At the same time,corn distillers' grains and highland barley distillers' grains had lower pH(P<0.05),however the pH value were in the normal range.(2)The concentrations of MCP and NH3-N of barley brewers' grains were higher than the others(P<0.05),Luzhou-sorghum distillers,grain was the lowest(P<0.05).TVFA,acetic acid and propionic acid of corn distillers' grains and highland barley distillers' grains were significantly higher than the others(P<0.05),and Luzhou-sorghum distillers' grain was the lowest(P<0.05).The ratio of acetic acid to propionic acid proportion of sorghum distillers' grains was significantly higher than the others(P<0.05).Trial 3.Study on the correlation between nutritional components and in vitro fermentation characteristics of distillers' grains(1)The total gas production of distillers' grains at 48 h in vitro fermentation was significant negative correlated with the contents of NDF(r=-0.734,P<0.01)and ADF(r=-0.759,P<0.01);the total gas production at 48 h in vitro fermentation was positively correlated with NFC(r=0.820,P<0.01)content.(2)The total gas productions at different time points in vitro fermentation of distillers'grains were positively correlated with the contents of CB1 and NSC;the total gas production at 4h,6h,8h,12h,24h and 48h in vitro fermentation were negative correlated with CC content.And,the total gas productions at 12 h in vitro fermentation was the highest positively correlated with CB1(r=0.801,P<0.01);the total gas productions at 8 h in vitro fermentation was the highest positively correlated with NSC(r=0.905,P<0.01);the total gas productions at 48 h in vitro fermentation was the highest negatively correlated with CC(r=-0.735,P<0.01).Parameters of gas production b and a+b were positively correlated with CB1(r=0.628,P<0.01;r=0.578,P<0.01),CB2(r=0.537,P<0.01;r=0.558,P<0.01)and NSC(r=0.774,P<0.01;r=0.803,P<0.01);and negatively correlated with CC(r=-0.706,P<0.01;r=-0.713,P<0.01)and PC(r=-0.490,P<0.05;r=-0.527,P<0.01).(3)At 48 h in vitro fermentation,the concentrations of MCP and NH3-N were positively correlated with CA(r=0.514,P<0.05;r=0.617,P<0.01),PB2(r=0.685,P<0.01;r=0.754,P<0.01)and PB3(r=0.785,P<0.01;r=0.846,P<0.01),and were negatively correlated with content of CHO(r=-0.702,P<0.01;r=-0.675,P<0.01),CC(r=-0.603,P<0.01;r=-0.711,P<0.01)and PC(r=-0.556,P<0.01;r=-0.623,P<0.01).VFAs were positively correlated with CB1(r=0.686,P<0.01),CB2(r=0.621,P<0.01),NSC(r=0.702,P<0.01)and PB2(r=0.624,P<0.01),and were negatively correlated with content of CC(r=-0.885,P<0.01),PC(r=-0.653,P<0.01).In summary,the nutrients composition and in vitro fermentation parameters of different types of distillers' grains are different.Based on the CNCPS evaluation,the protein quality of distillers' grains decrease sequentially from barley brewers' grains,corn distillers' grains,highland barley distillers' grains,Maotai-sorghum distillers' grains,to Luzhou-sorghum distillers' grains,and the quality of carbohydrates decrease from corn distillers' grains,highland barley distillers' grains,barley brewers' grains,Maotai-sorghum distillers' grains to Luzhou-sorghum distillers' grains.The fiber constituents in the distillers'grains are the main factors that inhibit theirs fermentability.PB2 and PB3 are favorable for the synthesis of MCP.CB1,CB2 and NSC are favorable for the formation of TVFA,while CC and PC inhibit their production.The rumen fermentation characteristics of distillers'grains can be predicted using the CNCPS fractions. |
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