| This paper studied the effects of different combinations of branched-chain amino acids on ruminal fermentation parameters and microbial flora diversity through three experiments. We have confirmed the best proportion of BCAA(Val,Leu and Ile) between fodder concentrate and coarse fodder,under different mixture ratio.Through adding BCAA into fodder of sheep,we have clarified its effect on sheep’s digestive system,and revealed the mixture ratio of BCAA have some effection on the diversity of rumen microbial and the growth of fiber degrading bacteria.Test 1: Throgh ermentation culture in vitro and the orthogonal experiment,we hope to find out the effection of 16 kinds of BCAA(Val, Leu and Ile) combination on ermentation culture in vitro, when they are added into fodder at the different rate of 20:80,40:60 and 60:40. The results showed that: when the rate was 20:80, the concentrations of isobutyric acid and pentanoic acid were significantly increased(P<0.05) with the increasing of valine level; the concentration of isovaleric acid increased with the increasing of isoleucine level.when it was 40:60,the concentration of isobutyric acid significantly increased with the ingcreasing of valine.With the increasing supplementation of isoleucine and leucine, pentanoic acid had differently degreeds increase.And when we added 0.67mmol/L valine to the fodder at the same ratio, the results showed that the concentration of isovaleric acid was the lowest.when it was 60:40, Isobutyric acid is mainly affected by the influence of valine.isovaleric acid was Effected by leucine and isoleucine,Valproic acid waseffected by valine and isoleucine.in conquence, the combination of BCAA had not obvious effection on pH, acetic acid/propionic acid and the degradation rate of NDF in 3 different mixture ratioes.Test 2: Second experiment: On the basis of test 1, Forage to concentrate ratio of 20:80 with 4 * 4 Latin square design, Study effect of adding 3 group mixed of BCAA the parameters of sheep rumen fermentation and whole digestion metabolism of nutrients. Three kinds of branched chain-amino acid combinations were combination 1(Val 0.67, Leu 0, Ile 0.67 mmol/L), combination 2(Val 0.67, Leu 1.33, Ile 2 mmol/L),combination 3(Val 0.67, Leu 2, Ile 1.33 mmol/L). The results show that: Add the three groups mixed of BCAA had acetic acid, propionic acid, butyric acid, TVFA, pH and other nutrients not significantly different(P>0.05). Adding of branched-chain amino acid composition 2 made the retention rate of P, concentration of NH3-N higher than other groups in each sampling time. The concentration of NDF and TVFA was the highest in the combination of 3, which was significantly higher than that in the control group(P<0.05).Test 3: On the basis of test two, Effect of microbial flora of rumen was analyzed by PCR-DGGE and high-throughput sequencing because of adding branched chain-amino acid. The results show that: The addition of BCAA changed the composition of rumen microorganism number and the structure of the community, the abundance of Victivallis, Bacteroides, Butyrivibrio and unclassified Eurotiales sp had significant effect. The addition of 3 different combinations of BCAA all can make the Succiniclasticum abundance have a trend of increasing.The adding of the valine, leucine and isoleucine’s levels were 0.67, 2.00, 1.33mmol/L, which made butyrivibrio genus abundances raised up 34.88%(P<0.05).From the above:Roughage ratio of 20:80, added concentration of valine,leucine and isoleucine was 0.67, 2, 1.33 mmol/L which can make the DM and NDF degradation rate reached the maximum in vitro; Changed diversity of the rumen microbial by increased abundance of butyrivibrio, reduce abundance of Victivallis and Bacteroides in vivo. |
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