ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2016, Vol. 47 ›› Issue (10): 2060-2070.doi: 10.11843/j.issn.0366-6964.2016.10.015

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Effect of Dietary Nutrient Levels on the Number of Related Microbes,pH and VFA Levels in Rumen of Tan Sheep Aged from 150 to 180 Days

WANG Yao-yue,ZHAO Zhao-yan,WANG Xing-tao,CHEN Yu-lin*,YANG Yu-xin*   

  1. (College of Animal Science and Technology,Northwest A&F University,Yangling 712100,China)
  • Received:2016-04-19 Online:2016-10-23 Published:2016-10-23

Abstract:

The aim of this experiment was to study the effect of dietary nutrient levels on the number of related microbes,including Succinivibrio dextrinisolvens(S.dextrinisolvens), Prevotella ruminicola(P.ruminicola),Selenomonas ruminantium(S.ruminantium),Butyrivibrio fibrisolvens(B.fibrisolvens),Ruminococcus flavefaciens(R.flavefaciens),Veillonella parvula(V.parvula) and Methanogens,pH and VFA levels in the rumen of Tan sheep aged from 150 to 180 days.One hundred and twelve 105-day-old Tan sheep(half males and half females) with the similar average body weight (BW) of (29±1.25) kg and better body condition were allotted randomly to 4 dietary treatments (group Ⅰ,Ⅱ,Ⅲ and Ⅳ).Each treatment had 4 replicated pens,with 7 sheep in each pen.From group Ⅰ to Ⅳ,energy of diets were 7.08,8.09,9.10 and 10.11 MJ• kg-1,respectively;dietary protein levels were 8.04%,9.19%,10.34% and 11.49%,respectively.The ratio of energy to protein was kept unchanged (about 0.88).The experiment lasted for 75 days,including 15 days for adaptation.On 150 and 180 days of age, one sheep was randomly selected in each replicate for slaughter and rumen contents were collected,pH was tested and VFA levels in the rumen were analyzed by gas chromatography measurement.Genomic DNA was extracted from rumen contents,qRT-PCR was used for the absolute quantification of these related microbes by the consruction of the standard plasmids.The result showed that the number of S.ruminantium on different days of age were significantly different (P<0.05).However,with the increasing of dietary nutrient levels,the number of P.ruminicolaR.flavefaciensS.dextrinisolvensB.fibrisolvens and Methanogens increased significantly (P<0.05).With the distinct days of age and dietary nutrient levels,pH was not significantly different (P>0.05).The content of acetate acid showed significantly downward trend from lower dietary nutrient levels to higher dietary nutrient levels(P<0.05).The ratio of butyrate,isobutyric,pentanoic acid and isovaleric to total volatile fatty acid (TVFA) showed significantly upward trends(P<0.05).There were mutually improved relationships between different rumen microbes.Propionic acid content was significantly and positively correlated with the number of V.parvula(r=0.42,P<0.05),while the content of pentanoic acid was extremely significantly negatively related to the number of V.parvula (r=-0.53,P<0.01).Compared with the effect of days of age,different nutrient levels have greater effects on rumen microbes and VFA levels.There are correlations between the levels of rumen VFA,pH and related ruminal microbes.

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