Effects Of Exogenous Fibrolytic Enzyme On Methane Emissions And Feed Efficiency For Sheep

Methane is a greenhouse gas, rumen methane emissions decreased the feed energy utilization of ruminant. Therefore, reducing ruminant methane emissions more and more the concern of the community. In present study, respiration calorimetry room was used to study the effects of exogenous fibrolytic enzyme in methane emissions and feed utilization.A total of12boer crossbred goats were selected and assigned randomly to3treatments, including1basal diet (control) and2experiment diets (basal diet+0.2%cellulose, basal diet+0.2%compound cellulose), each treatment contained six goats. The design of experiment was3×3Latin square. The experiment lasted for21days, include14days of pre-feeding period and9days metabolism trial period. To collect all dung and urine start from the fourth day of metabolism trial period. To collect the samples for everyday kept at low temperature. Animals were confined in the chamber for the last3days of metabolism trial period. The first day was the adaptation. The end of the test, we were collected the tumour gastric juice and the blood. The results showed that (1) Exogenous cellulases supplementation could improved the utilization of the feed, significantly increased the apparent digestibility of ADF, NDF and CP(p<0.05), significantly reduced the excretion of fecal nitrogen and urinary nitrogen(p<0.05). Significantly increased nitrogen deposition rate and net nitrogen utilization (p<0.05) in condition of there were no difference in feed nitrogen;(2) there were no effect on gas energy and body heat gain by dietary cellulose(p>0.05), however, significantly reduced the loss of dung and urine energy(p<0.05). Compared with control group, the digestive energy and metabolic energy of experimental group were higher in condition of there were no difference in feed nitrogen, but, there was no difference on methane gas generation, methane emissions per kg dry matter intake and the ratio of methane emissions to the total energy;(3) dietary cellulose could improved rumen fermentation of boer crossbred goats, adding single cellulase treatment group the total volatile fatty acid, acetic acid, propionic acid and butyric acid content has a tendency to increase (p<0.1), adding compound cellulase treatment group total volatile fatty acid, acetic acid, propionic acid and butyric acid content were significantly lower than control group (p<0.05) and anding single cellulase treatment group(p<0.01), however, both single cellulase and compound cellulase could not effect rumen environment, rumen pH, the content of ammonia and lactic acid, the ratio of acetic acid to propionic acid and the ratio of volatile fatty acids to total volatile fatty acids.(4) dietary cellulase could affect the count of cellulolytic microorganisms in the rumen, increased white rumen bacteria, producing succinic acid fiber bacteroides, insoluble fiber butyrivibrio and protozoa(p<0.01), complex enzyme could reduce the count of yellow ruminococcus, thecount of methane-producing bacteria of cellulase group was higher than the complex enzyme group(p<0.05).(5) There were no difference of exogenous cellulose on serum alanine aminotransferase, urea nitrogen, total cholesterol and creatinine in boer crossbred goats(p>0.05).In conclusion, the exogenous cellulose supplementation could improved the utilization of roughage diet in sheep, increased the deposition rate of the nitrogen, increased digestible energy and metabolizable energy of diet. And also improved rumen fermentation, improved the proliferation of rumen cellulolytic bacteria, However, the increased of the cellulase had no effect on methane emissions.