Effects Of Diet Types On Rumen Methane Production And Microbial Diversity Is Inner Mongolia Cashmere Goats

Methane produced in the rumen of ruminants not only causes an increase in greenhouse gases,but also reduces feed utilization.In this study,alfalfa green hay,alfalfa green hay plus concentrate,cornstalk,and cornstalk plus concentrate were selected as experimental diets.Under the production conditions,8-month-old Inner Mongolia cashmere goats were fed with different types of diets in order to research the impact of diet types on CH4 emission and rumen fermentation characteristics,and high-throughput sequencing technology was used to analyze the diversity of rumen microbes.The purpose is to analyze the changes and interactions of microorganisms associated with methane production in the rumen,and reveal the impact of rumen microbial activity on methane production,and provide theoretical and technical support for the future assessment of animal methane emission and its reduction.1.The results of rumen methane emissions from cashmere goats showed that the daily output of CH4(12.63 L/d)in the alfalfa supplemented concentrate group was lower than that in the alfalfa group(14.97 L/d),but the difference was not significant(P>0.05).The daily output of CH4(18.22 L/d)in the cornstalk supplemented concentrate group was lower than that in the cornstalk group(21.11 L/d),and the difference was significant(P<0.05).The daily output of CH4 in the alfalfa group was significantly lower than that in the cornstalk group(P<0.01).Supplementing concentrate has a tendency to increase the hydrogen concentration,but the difference between the groups is not significant.2.The results of research on the rumen fermentation characteristics of cashmere goats showed that the effects of different types of diets on the pH,BCP concentration,butyric acid concentration and the ratio of acetic acid to propionic acid in rumen fluid of cashmere goats were not significant(P>0.05).The concentration of NH3-N(11.90 mg/100mL)in the rumen fluid of alfalfa supplemented concentrate group was significantly higher than that in other groups.The concentration of propionic acid,valeric acid,isovaleric acid in the alfalfa group and the alfalfa supplemented concentrate group were significantly higher than that in the cornstalk group and the cornstalk supplemented concentrate group(P<0.01).The concentration of acetic acid and TVFA in the alfalfa group and the alfalfa supplemented concentrate group were signilicantly higher than that in the cornstalk group and the cornstalk supplemented concentrate group(P<0.05).3.The research results of rumen microbial diversity showed that:(1)The abundance of ruminal methanogens,bacteria,and fungi increased after supplementing with concentrate.The abundance of methanogens and bacteria in the alfalfa group was higher than that in the cornstalk group,and the abundance of fungi was significantly lower than that in the cornstalk group.(2)The predominant phylum of methanogens in the alfalfa group was Euryarchaeota.The predominant phylum of methanogens in the alfalfa supplemented concentrate group,cornstalk group and cornstalk supplemented concentrate group were norank d Bacteria,and the dominant methanogens on family and genera levels were norank d Bacteria.(3)The predominant phylum of rumen bacteria in different diet groups were Bacteroidetes,and the predominant bacteria family was Prevotellaceae,and the predominant genus was Prevotella.(4)The dominant phylum and genus of rumen fungi in different diet groups were Ascomycota and Aspergillus.The predominant family of fungi in the alfalfa group or the alfalfa supplemented concentrate group were Aspergillaceae and Neocallimastigaceae.The predominant family of fungi in the cornstalk group or the cornstalk supplemented concentrate group were Aspergillaceae and Trichosphaeriaceae.4.The results of rumen protozoa research showed that supplementing concentrate could reduce the number of rumen protozoa in cashmere goats.The number of protozoa in the cornstalk group was higher than that in the alfalfa group.