| Ruminants can convert forage into meat and milk that human beings require, the gastrointestinal microbes play an important role in it. Bacteria, protozoa, fungi and methanogens comprise a complicated microecosystem in rumen. They degrade feedstuff and supply nutrients for ruminants. However, the methane as one of the fermentation end products is considered to be a loss of feed energy and contribute to global warming. Scientists have been trying to understand the relationships between rumen microorganisms and to find strategies to reduce methane emission from ruminants. This study using goats as experimental animal was to investigate the effects of anaerobic fungi on feedstuff degradation, body healthy, methanogens and methane emission.In the first section, eight male goats with permanent rumen fistulae were chosen for this study to investigate the effects of inhibiting the rumen fungi on nutrient digestibility and physiological status of goats. Results showed, after the rumen fungi were inhibited, the apparent digestibility of dry matter, organic matter, crude protein, neutral and acid detergent fiber decreased slightly, but were not changed significantly (P>0.05). Inhibiting the rumen fungi also had no significant effects (P>0.05) on the body weight and blood parameters (TP, GPT, GOT, BUN, GLU, TG, CHOL) of goats. The results indicated that anaerobic fungi may have roles in fiber degradation in rumen, inhibiting anaerobic fungi in part had no negative effect on body healthy of goats.In the second section, the study was carried out to investigate the effects of inhibiting the rumen fungi on the ruminal fermentation in goats. Results showed that when the rumen fungi were inhibited, the rumen pH value increased significantly (P<0.05), while the ammonia nitrogen concentration in the rumen fluid decreased significantly (P<0.05). There were no significantly changes (P>0.05) in the microbial protein and propionate concentration in the rumen. The total VFA, acetate, butyrate concentration, the molar percentage of acetate/propionate and the methane emission decreased significantly (P<0.05). After the rumen fungi were resumed, the rumen pH value decreased significantly (P＜0.05), the total VFA concentration increased significantly (P<0.05), the ammonia nitrogen, acetate, butyrate concentration and the molar percentage of acetate/propionate had no significant differences (P>0.05) with that in the control period and treatment period. The methane emission increased significantly (P＜0.05). The results indicated that the rumen fermentation pattern was changed with inhibition of anaerobic fungi, the fermentation speed of carbohydrate slowed, and the production of VFA and methane in rumen delayed. The fermentation of anaerobic fungi may be acetate type in rumen and had a certain contribution to methane emission in the rumen.In the third section, Real-time PCR, ARISA and T-RFLP were used to investigate the population and diversity of fungi and methanogens in solid-and liquid-phase of rumen and their changes during the trial. Results showed that the gene copies of anaerobic fungi associated with rumen solid content per gram were3300-fold (P<0.05) as those in rumen liquid content per milliliter, while there was no significant difference (P>0.05) of gene copies of methanogens in the two parts of rumen content. After the treatment of fungal inhibition, the gene copies of anaerobic fungi associated with rumen solid content reduced by83.48%(P＜0.05), the populations of fungi in liquid phase and methanogens in solid/liquid phase of rumen content did not show significant changes (P>0.05). The gene copies of anaerobic fungi in rumen solid content increased significantly (P＜0.05) during the recovery period. The structures of anaerobic fungi and methanogens in rumen had no significant vibration. |
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