Effects Of Isoacids On Rumen Microflora Of Goat

Basis in the artificial rumen technique,in this experiment,Relatively Quantitative PCR and PCR-SSCP technique were used to investigate the effects of 2-methylbutyrate, Isobutyrate,Isovalerate,Valeric acid and their appropriate proportion of the mixture on rumen microflora of goat. 0.2% compound isoacids were added to study the effect of the different levels of NPN on rumen microflora of goat. The effect of compound isoacids on rumen microflora of goat were studied by adding isoacids in the goat diet.In this experiment, the results were shown as follows:Exp.1 The effect of four monomer isoacids and compound isoacids on goat rumen microflora ,under the condition ruminal fermentation in vitroUsed a single-factor trial, the experiment was divided into five treatments ,and each treatment included three replicates. According to the goat metabolic body weight, dry matter intake and dry matter content in the diet, four monomer isoacids and 0.2% compound isoacids were added. After 24-hour gas production in vitro, culture medium was collected. The microorganisms DNA was extracted from culture medium above. As a reference with the microorganisms DNA, semi-quantitative PCR was carried out. The region V3 of the 16S rDNA of rumen bacteria was analyzed by PCR-SSCP technique. The results demonstrated that the change trend of expression from each rumen bacterium was not consistent. The effect of compound isoacids on cellulose decomposing bacteria was higher than four monomer isoacids, but the difference is not significant(P>0.05). However, The effect of compound isoacids on starch decomposing bacteria was lessr than four monomer isoacids, but the difference is not significant(P>0.05). SSCP analysis showed that characteristic bands of rumen bacteria in each treatment group were different, and each treatment group had its own dominant bacteria.There was the most bands in compound isoacids group.Exp.2 Conditions in compound isoacids the effect of the different NPN levels on rumen microflora of goatUsed in vitro gas production method and a single-factor trial, In the light of dry matter content in the die, adjunction of NPN was setted to five levels: 0 (a control group),0.3%,0.6%,0.9% and 1.2%, respectively, and each level included two replicates. 0.2% compound isoacids were added. After 24-hour gas production in vitro, culture medium was collected. The microorganisms DNA was extracted from culture medium above. As a reference with the microorganisms DNA, semi-quantitative PCR was carried out. The region V3 of the 16S rDNA of rumen bacteria was analyzed by PCR-SSCP technique. The results demonstrated that under adding compound isoacids conditions, comprehensive consideration the expression of five rumen bacteria, the effect of 1.2%NPN was the best. SSCP analysis showed that the profiles had high similarity among control group,0.3%NPN group,0.6%NPN group and 0.9%NPN group. 1.2%NPN group obviously increased bacterial bands, therefore, the diversity of rumen bacteria was more complex in this group.Exp.3 The effect of compound isoacids on goat rumen microfloraThe experiment was divided into control period and trial period. Goats were fed basal diet during control period, while they were fed basal diet supplementing 0.2% compound isoacids during trial period. Before this experiment, 2 weeks Pre-feeding was executed. At 7th day and 14th day in every period, the rumen content samples were collected from fixed cannulas. The microorganisms DNA was extracted from culture medium above. As a reference with the microorganisms DNA, semi-quantitative PCR was carried out. The region V3 of the 16S rDNA of rumen bacteria was analyzed by PCR-SSCP technique. The results demonstrated that the expression of five rumen bacteria increased as the extension of compound isoacids added time. SSCP profiles showed that rumen bacterial flora obviously changeed. Compared with the control period, During the trial period, the number of bands increased in SSCP profiles, and the number of bands was the most in the 14th day.