The Effect Of Different Doses Of Saccharomyces Cerevisiae On Enteric Methane Emissions And Production Performance Of Beef Cattle

Combined with the typical feeding mode of central plains,this experiment explored the effects of different doses of saccharomyces cerevisiae on rumen fermentation,enteric methane emissions and production performance with the diet unchanged,seeking the effective doses of saccharomyces cerevisiae.Experiments were conducted as follows:Experiment 1: This study was investigated to evaluate the effects of different doses of saccharomyces cerevisiae culture on rumen gas,methane production,p H,ammonia nitrogen?NH₃-N?and microbial crude protein?MCP?in vitro.The treatments included four groups?A,B,C and D?.Saccharomyces cerevisiae culture(the number of live bacteria was 3.5×108CFU·m L^-1)was added at levels of 0 m L,0.5 m L,1.0 m L and1.5 m L to the A,B,C and D,repectively.In other word,saccharomyces cerevisiae culture was added at levels of 0,8.38 mL·mL^-1,16.67 mL·mL^-1 and 25 mL·mL^-1 in artificial rumen fluid,respectively.The results showed that the total gas production for 24 h of C and D were significant higher than that of A?P<0.05?,and the total methane production for 24 h of D was extremely significant lower than that of A?P<0.01?.The pH of C and D were extremely significant lower than that of A?P<0.01?,and the pH of B was significant lower than that of A?P<0.05?;There was no significant difference between each groups on NH₃-N contents?P > 0.05?;The MCP contents of D was significant higher than that of A?P<0.05?,the differences of MCP contents was not significant beteewn the rest three groups?P>0.05?.The acetate:propionate ratio of C and D were extremely significant higher than that of A?P<0.01?,but the differences of acetate: propionate ratio was not significant beteewn the B andA?P>0.05?.Conclusion: Total gas,MCP contents and acetate: propionate ratio of rumen fermentation in vitro were significiantly increased by adding saccharomyces cerevisiae culture?25mL·mL^-1(the number of live bacteria was 3.5×108CFU·mL^-1).Methane productions and NH₃-N contents of rumen fermentation in vitro were significiantly reduced by adding saccharomyces cerevisiae culture?25mL·mL^-1(the number of live bacteria was 3.5×108CFU·mL^-1).Experiment 2: The objective of the experiment was to investigate the effects of different doses of saccharomyces cerevisiae supplementation on production performance,dry matter intake and digestibility efficiency of nutrition of beef cattle.Thirty-two healthy Simmental crossbred beef cattle?246.18±6.63kg?were randomly and equally divided into four experimental treatments: A was control groups,fed with normal basic diet;Besides the basic diet,B,C and D were fed with saccharomyces cerevisiae(the number of live yeast cells?2×1010·g^-1),the doses of saccharomyces cerevisiae supplementation were 3g·?head·d?^-1,6g·?head·d?^-1and 9g·?head·d?^-1.Four animals were chosen from each group to conduct the feed intake and digestion and metabolism experiments during d38 to 40.The results showed that there was no significant effects of saccharomyces cerevisiae on dry matter intake?DMI?of experimental cattle?P>0.05?.The average daily gain?ADG?of C and D were extremely significant higher than that of A?P<0.01?,and the gross profit per head per day of C and D were increased by 27.63% and 24.01% than that of A.The phosphorus apparent digestibility of C and D were extremely significant decreased by28.58% and 30.12% than that of A?P<0.01?.The apparent digestibility of neutral detergent fiber?NDF?of C was significantly increased by 34.23% than that of A?P<0.05?;The apparent digestibility of acid detergent fiber?ADF?of D was increased by 40.31% than that of A?P<0.01?and 23.15% than that of B?P<0.05?,and had no significant differences with C?P>0.05?.There was no significant effects of saccharomyces cerevisiae on the apparent digestibility of crude protein?CP?and general energy?GE??P>0.05?.The results suggested that 6g·?head·d?^-1 or 9g·?head·d?^-1of saccharomyces cerevisiae supplementation can significant increase the production performance and the digestibility efficiency of nutrition of beef cattle.Experiment 3: The objective of the experiment was to investigate the effects of different doses of saccharomyces cerevisiae supplementation on methane emissions of beef cattle.Four animals were chosen from each group to deliver the known permeation rate of penetration tubes on d19,and the SF6 tracing method was used todetermine the methane emissions from d33 to 37.The results showed that the trend of enteric methane emission production from the four groups of experimental cattle was roughly consistent during the 5 sampling days.The average emission level of A was the highest,which of C was the lowest,and C changes the most gentle.The total methane emissions of beef cattle A<D<B<C,the total methane emissions of C was extremely significant lower than that of A?P<0.01?.The methane emission per unit of body weight A>D>C>B,there was no significant differences between each groups?P > 0.05?.The methane emission per unit of feed intake A<D<B<C,and the methane emission per unit of feed intake of C was significant lower than that of A?P<0.05?.The results suggested that 6g·?head·d?^-1 of saccharomyces cerevisiae supplementation can significant reduce enteric methane emission production of beef cattle.Above all,combined with the effect and the economy cost of Saccharomyces cerevisiae,the best additional dose of saccharomyces cerevisiae was 6g·?head·d?^-1.This additional dose can make the economic benefit reach the top,and maximum decrease the enteric methane and increase the production performance of beef cattle.