| The objective of this study was to analyse nutritional value and evaluate safety of alfalfa hay in five regions of northern China.95 samples of alfalfa hay from 44 representative large-scale prataculture companies in the major alfalfa planting regions were collected during June 15 to August 24,2017,including Northeast Plain(NP),Inner Mongolia Plateau(IMP),Northwest Desert Oasis(NO),Loess Plateau(LP)and Huanghuaihai Plain(HP)..These samples analysis were carried out in Laboratory.The results showed that: The first test:(1)The gray correlation analysis of the nutritional value of alfalfa hay in different regions indicated(Rank from high to low): NO,IMP,NP,HP,LP.Combined that with the results of cluster analysis,the alfalfa hay nutritional value of NO was the highest,those of IMP,NP and HP were medium,that of LP was the lowest.(2)There were no significant differences was found on the contents of CP,ADF and Ash in the alfalfa hay among 5 regions(P>0.05).Their NDF,EE and DM showed significant differences in different degions.The mean of nutrition composition content of alfalfa hay in China were followed: CP was 16.43%,NDF 44.01%,ADF 33.22%,Ash 10.78%,and DM was 91.90%,which belonged to the second grade alfalfa hay according to national standard.(3)The correlation analysis results of alfalfa hay nutrition composition showed that CP content had very significant negative correlation with NDF and ADF(P<0.01),and very significant positive correlation with P(P<0.01).There was very significant positive correlation between NDF and ADF content(P<0.01),while it had very significant negative correlation with P(P<0.01).Significant negative correlation and significant positive correlation were between ADF and P(P<0.05),and P and EAA(P<0.05),respectively.There was no significant correlation among the other nutrition compositions.(4)The contents of EAA and TAA of the alfalfa hay in IMP was higher than the other regions,but the difference was not significant(P>0.05),while its ALA and PUFA contentsinwere significantly higher than those of other four regions(P<0.05),and the contentof mineral elements of this region was also higher comparing with other regions.The second test:(1)The evaluation results of Nemerow comprehensive pollution index showed(Rank from high to low): LP,NO,IMP,HP,NP.The five regions were not contaminated by mycotoxins(AFB1,DON,ZEN),but those were slightly polluted by microbe (bacteria,mold).Alfalfa hay in China had not be contaminated by heavy metals except Cr i.(2)There were no significant differences in the contents of AFB1,ZEN,As,Cd,Pb and Cu in alfalfa hay of each region(P>0.05).The DON content of alfalfa hay in IMP was significantly higher than that those of NP and LP(P<0.05);that of LP was the lowest and significantly lower than IMP,HP and NO(P<0.05).Cr of NP was significantly higher than those of the other four regions(P<0.05).Zn of LP and HP were significantly higher than that of NO(P<0.05),no significant differences was found in NP and IMP(P<0.05).(3)The correlation analysis results showed that AFB1 had significant negative correlation with TBC and TMC(P<0.05);very significant negative correlation was between Cu and Zn(P<0.01);There was no significant correlation among the other safety components.(4)The detection rate of mycotoxin,microbe and heavy metals in all alfalfa hay samples of north China was 100%.The over-limit rate of DON,TBC and TMC were 6%,66.7% and 75.8%,respectively.And that of Cr in heavy metals was as high as 87.9%.In addition,other safety components had not exceeded the national standard.In summary,the alfalfa hay nutritional value of NO was the highest,safety was high nutritional value of IMP was high,safety was medium;nutritional value of NP was medium,safety was the lowest;nutritional value of HP was low,safety was also low;nutritional value of LP was the lowest,while safety was the highest. |
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