Evaluation Of Protein Nutrition Value Of Corn Silage By FTIR Technology

Because that protein molecular structures influenced feed nutrition value and digestive utilization,the objective of this present research was to rapidy evaluation of protein nutrition value of corn silage by investigating the relationship between nutrition value(common nutrient contents, protein fractions partitioned by CNCPS, rumen degradation characteristics) of corn silages with protein molecular structures, and established regression equations.Protein fractions of 11 kinds of corn silages were partitioned by Cornell Net Carbohydrate and Protein System(CNCPS) model, rumen degradation characteristics(dry matter, curde protein and neutral-detergent fibre) were determined by nylon bag technique and protein molecular structures(amide I, amide II, α-helix, β-sheet) were determined by Fourier transform infrared spectroscopy(FTIR).The results showed that: the height of amide II had a very significant correlation with acid detergent insoluble crude protein(ADICP)(r=-0.57, P<0.01), undegradable protein sub-fraction(PC)(r=0.57, P<0.01) and effective degradable rate of dry matter(DMED)(r=-0.71, P<0.01), but had a significant correlation with degradation rate of slowly degraded part(NDFc)(r=-0.52, P<0.05) and none degraded part of neutral-detergent fibre(NDFu)(r=-0.46, P<0.05); at the same time, the ratio of amide I height to amide II height had a very significant correlation with sol uble crude protein(SCP)(r=0.75, P<0.01),rapidly degradable protein sub-fraction(PA)(r=-0.72, P<0.01), rapidly degraded part of dry matter(DMa)(r=0.57, P<0.01), slowly degraded part of dry matter(DMb)(r=-0.55, P<0.01); had a significant correlation with nonprotein nitrogen(NPN)(r=0.42, P<0.05), none degraded part of crude protein(CPu)(r=-0.50, P<0.05), but tended to have a significant correlation with effective degradable rate of crude protein(CPED)(r=0.38, P<0.10); the ratio of amide I area to amide II area had a very significant correlation with intermediately degradable protein sub-fraction(PB2)(r=0.84, P<0.01); the height of α-helix had a very significant correlation with crude protein(CP)(r=0.68,P<0.01), neutral detergent insoluble crude protein(NDICP)(r=0.63, P<0.01), slowly degradable protein sub-fraction(PB3)(r=0.68, P<0.01), none degraded part of dry matter(DMu)(r=0.59, P<0.01), at the same time it also had a significant correlation with rapidly degraded part of crude protein(CPa)(r=0.45, P<0.05); the height of β-sheet had a very significant correlation with intermediately degradable protein sub-fraction(PB2)(r=-0.73, P<0.01); the ratio of α-helix to β-sheet had a very significant correlation with degradation rate of slowly degraded part of dry matter(DMc)(r=0.59, P<0.01) and degradation rate of slowly degraded part of crude protein(CPc)(r=0.57, P<0.01); had a significant correlation with effective degradable rate of crude protein(CPED)(r=0.43, P<0.05) and effective degradable rate of neutral-detergent fibre(NDFED)(r=0.42, P < 0.05), but no correlation(P>0.10) had found between protein molecular structures with true protein soluble in buffer(PB1), slowly degraded part of crude protein(CPb), rapidly degraded part of neutral-detergent fibre(NDFa) and slowly degraded part of neutral-detergent fibre(NDFb).These results indicated that FTIR could be used to analysis the relationship between protein nutrition value of corn silages with protein molecular structures and esta blish regression equations. Among theses equations, protein molecular structures indicated CP(R2=0.46), SCP(R2=0.56), PA(R2=0.52), PB2(R2=0.87), PB3(R2=0.46), DMED(R2=0.50) and CPED(R2=0.48) well. With the quantitative relations, analyzing nutritional values of corn silages would be rapidly and non-destructively, thus reducing the disadvantages of environmental pollution, time-consuming and laborious in traditional chemical analysis methods.