Effects Of Eliminating Anaerobic Fungi And Defaunation Respectively On Ruminal Microbes And Fiber Digestibility In Sheep

The aim of cureent research was to study effects of ruminal microorganisms and their interactions on fiber digestion, rumen fermentation parameters, fibrolytic enzyme activity and digesta passage rate under high forage diets (forage to concentrate ratio was 80: 20) by eliminating anaerobic fungi (EF) and defaunation (DF) respectively in sheep for pursuing the reasonable suggestion to improve the utilization of fiber in rumen. Ruminal microorganism count was conducted by real-time PCR and traditional roll tube method respectively to hunt for precise quantification approach of rumen microbes.Two trials were carried out and each trial included 6 healthy, 35 Kg body weight and 1.5 aged Mongolia sheep randomly assigned into two groups (control and treatment). In trial I treatment group, the anaerobic fungi were eliminated. After the sampling, the anaerobic fungi were introduced (IF) into the rumen of sheep. The same way was used in trial 2, in which samples were collected two times after defaunation (DF) and refaunation (RF).After EF, the digestibility of dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were significantly decreased (p<0.05), but the digesta passage rate was not changed. Total quantities of bacterial, cellulolytic bacterial and protozoa were significantly increased (p<0.05). Among three main cellulolytic bacteria species (R.albus, R.flavefaciens and F.succinogenes), the quantities of R.flavefaciens and F.succinogenes were significantly increased (p<0.05). The EF resulted in a decrease (p<0.05) of activity of CMCase, total VFA and acetate, whereas the activity of FPA, xylanase and pectinase were not changed. The ruminal pH value increased and the concentration of NH3-N decreased after EF, but was not statisticaly significant.The DF resulted in a significant decrease (p<0.05) in digestibility of DM, NDF and ADF. After DE, the total ruminal bacterial quantities were significantly increased (p<0.05), whereas the cellulolytic bacterial counts were not affected by DF. The quantities of ruminal anaerobic fungi were not changed by traditional roll tube method, but quanitites of rumianl fungus were significantly decreased (p<0.05) by using real-time PCR detection, which indicated that two methods were not consistent. Quantities of R.albus and R.flavefaciens significantly increased but f F.succinogenes significantly decreased (P<0.05). The DF significantly decreased the activity of CMCase, FPA and pectinase, but had little effect on the xylanase. The ruminal pH value and total VFA were not affected by DF, while the concentration of propionate was significantly increased and concentration of butyrate and NH3-N was significantly decreased (p<0.05).The results of real-time PCR detection of ruminal microorganisms showed that the quantities of total rumianl bacteria and fungi were 10 and 1000 times higher than that of traditional roll tube respectively. The sensitivity and accuracy of real-time PCR were also superior to the traditional method. The results of three main cellulolytic bacteria quantities by real-time PCR suggested that it could be a useful tool in the quantitative research of single ruminal microorganism.The results of current study indicated removal of anaerobic fungi or protozoa would lead to a decrease of fiber degradation and cellulolytic enzyme activity, and it also brought about a change of ruminal microbial ecosystem. Real-time PCR was a more accurate and convenient method for quantitative study of ruminal microorganisms.