The Effect Of Different Forage To Concentrate Ratio And N Sources On The Population Of Sheep Ruminal Cellulolytic Microbes And Fiber Digestion

In this paper, traditional and modern molecular biological methods for detecting microorganisms were used to study the population of rumen cellulosis microbes under different forage to concentrate ratio and different nitrogen sources diets. Rumen fermentation parameters and cellulase were also measured to explain the fiber degradation mechanism . The experiment comprises two parts:1.Effect of different forage to concentrate ratio on the count of cellulosis microbes and rumen fermentation parameters9 Sunite sheep, healthy, weighting about 50kg, were randomized allocated in three groups (groupⅠ,groupⅡand groupⅢ). The ratio of concentrate to Forage were 1:9,3:7 and 5:5 for groupⅠ,groupⅡand groupⅢrespectively. The results obtained by traditional detecting method showed that there were no significant differences between groups in the population of rumen fungi and bacteria (P﹥0.05), however, the differences between groups in the number of Dasytricha,Diplodinium,Ophryoscolex were significant(P<0.05),which were highest for groupⅡ. The count of Cellulosis bacteria decreased with the increase of concentrate in the diet, and the differences between groups reached statistical significance (P<0.05).The same results were obtained by quantified hybridization and quantified PCR technique. The percentage of F.succinogenes among three major cellulosis bacteria was highest, and the effect of diet on the amount of F.succinogenes wasn't significant. The amount of R.. albus and R. flavefaciens detected by quantified PCR in groupⅡwere significant higher than that of groupⅢ(P﹤0.05).The results also indicated that with the increase of concentrate:forage pH value declined, and the difference between groups were significant ( P﹤0.01),however, the concentration of NH3-N and total VFA increased with the increase of concentrate:forage ratio,and that were the highest for groupⅢ(P﹤0.01). The mol concentration percentage of acetic acid significant decreased with the increase of concentrate:forage, however, the mol concentration of propionic and butyric acid significant increased.(P﹤0.05).There were no significant differences between three groups in solid fractional passage rate and fiber dynamic degradation coefficients(p﹥0.05).The differences between treatments in passage rate and digestibility in different digestive tract segments weren't significant (p﹥0.05), however, rumen fiber digestibility in groupⅠwas higher than that of groupⅡandⅢ, and the whole digestive tract fiber digestibility was lowest for groupⅢ. Liquid fractional passage rate was the highest for groupⅡ,and the difference was significant between groups(p﹤0.05). No significant difference was found between three groups in cellulase activity in rumen liquid digesta. Pectic enzyme in rumen solid digesta in groupⅢwas significant higher than of groupⅠandⅡ(p﹤0.05),and FPA in rumen solid digesta in groupⅠwas significant higher than of groupⅢ(p﹤0.05)2.Effect of different nitrogen sources on the count of cellulosis microbes and rumen fermentation parameters12 Sunite sheep, healthy, weighting about 50kg, were randomized allocated in four groups. Nitrogen sources of the diets were sunflowerseed meal+zein,fish meal,cottonseed meal and soybean meal for groupⅠ, groupⅡ, groupⅢand groupⅣrespectively. The results obtained by traditional detecting method showed that rumen anaerobic fungi counts in groupⅢwere significantly greater than of groupⅡand groupⅣ(P<0.05),however,there were no significant differences between groups in the population of rumen bacteria(P﹥0.05).Nitrogen sources had significant effect on the number of Entodinium,Protozoa(P﹤0.0001), meanwhile the same trend was also found in the count of Isotricha,Dasytricha,Diplodinium,Ophryoscolex(P﹤0.05),and the number of protozoa was highest for groupⅣand lowest for groupⅢ. The count of Cellulosis bacteria for groupⅢwas significant greater than for groupⅡand groupⅠ(P<0.05). The amount of F. succinogenes in groupⅢdetected by quantified PCR were significant higher than that of groupⅠ(P﹤0.05)whereas the amount of R.. albus and R. flavefaciens weren't significantly influenced by nitrogen sources(P﹥0.05). Nitrogen sources significantly influence rumen pH value, and pH of groupⅢwas significant higher than that of groupⅣ(P﹤0.05). No significant differences were found between groups in the concentration of NH3-N ,total VFA and butyric acid (P﹥0.05), however, the mol concentration percentage of acetic acid for groupⅡwas significant lower than for other groups(P﹤0.05)whereas the adverse result was observed for that of propionic acid(P﹤0.01).The results also showed that there were no significant differences between groups in solid fractional passage rate, liquid fractional passage rate, rumen volume and fiber dynamic degradation coefficients ( p﹥0.05).Activity of xylanase in rumen liquid digesta was significantly influenced by nitrogen sources(p﹤0.05),and the xylanase activity of groupⅡsignificantly higher than of groupⅢandⅣ(p﹤0.01).When compared with groupⅣ, groupⅢshowed significantly higher xylanase activity(p﹤0.05). Pectic enzyme in rumen solid digesta in groupⅢwas significant higher than that of groupⅠ(p﹤0.05),and indican enzyme in groupⅠwas significant higher than that of groupⅡ(p﹤0.05)whereas there was no significant difference between groupⅢandⅣin the indican enzyme. GroupⅡshowed significantly lower FPA activity in rumen solid digesta compared to other groups(p﹤0.01).