饲粮中添加桉叶油和茴香油对肉羊甲烷产量及瘤胃产甲烷菌区系的影响

Effects of Dietary Eucalyptus Oil and Anise Oil on Methane Production and Rumen Methanogens Community of Mutton Sheep

本试验旨在研究饲粮中添加植物精油(EOs)对肉羊甲烷(CH_(4))产量及瘤胃产甲烷菌区系的影响。试验采用3×3拉丁方设计,选用体重为(64.45±8.56) kg的6只健康杜寒F1代杂交成年瘘管羊,随机分配到3个组[不添加EOs的对照组、添加500 mg/(头·d)桉叶油的桉叶油组和添加500 mg/(头·d)茴香油的茴香油组]中,每组2只,共进行3期试验,每期22 d,其中预试期14 d,正试期8 d。试验期间采用呼吸测热室测定肉羊CH_(4)产量,试验期结束时取瘤胃食糜,采用荧光定量PCR测定肉羊瘤胃微生物数量;采用Illumina MiSeq高通量测序技术测定瘤胃产甲烷菌区系变化。结果显示:与对照组相比,饲粮中添加桉叶油对肉羊CH_(4)产量没有显著影响(P>0.05),但添加茴香油有使肉羊CH_(4)产量降低的趋势(P=0.08)。与对照组相比,饲粮中添加桉叶油或茴香油对肉羊瘤胃中总细菌、总真菌、总原虫和总产甲烷菌数量均无显著影响(P>0.05);饲粮中添加桉叶油显著降低了瘤胃甲烷短杆菌(Methanobrevibacter ruminantium)和未分类的甲烷短杆菌属(unclassified Methanobrevibacter)的相对丰度(P<0.05),极显著增加了Methanobrevibacter euryarchaeote的相对丰度(P<0.05);饲粮添加茴香油显著降低了Methanobrevibacter ruminantium的相对丰度(P <0.05),显著提高了unclassified Methanobrevibacter和Methanobrevibacter euryarchaeote的相对丰度(P <0.05)。综上所述,肉羊饲粮中添加500 mg/(头·d)桉叶油或茴香油对肉羊瘤胃微生物数量没有显著影响,但影响了瘤胃产甲烷菌区系,其中茴香油对CH_(4)产量数值上的降低可能是由于其降低了Methanobrevibacter ruminantium的数量。

This study was conducted to evaluate the effects of dietary plant essential oils(EOs)on methane(CH_(4))production and rumen methanogens community of mutton sheep.The experiment used a 3×3 Latin square design,six healthy F1 generation hybrid fistulas Duhan mutton sheep with the body weight of(64.45±8.56)kg were randomly allocated to 3 groups with 2 sheep per group,and the 3 groups were control group(without EOs),eucalyptus oil group[supplemented with 500 mg/(head·d)eucalyptus oil]and anise oil group[supplemented with 500 mg/(head·d)anise oil].A total of 3 stages of experiment were conducted for22 days each,including 14 days of pre-feeding and 8 days of formal experiment.During the experiment,the CH_(4)production of mutton sheep was measured by respiratory calorimetry chamber.At the end of the experiment,rumen digesta was collected and the microbial number of mutton sheep rumen was determined by fluorescence quantitative PCR,Illumina MiSeq high-throughput sequencing technique was used to determine the changes of the rumen methanogens community.The results showed that,compared with the control group,diet supplemented with eucalyptus oil had no significant effects on the CH_(4)production of mutton sheep(P>0.05),but the CH_(4)production had a decreasing tendency when diet supplemented with anise oil(P=0.08).The supplementation of eucalyptus oil or anise oil had no significant effect on the number of total bacteria,total fungi,total protozoa and total methanogens in rumen of mutton sheep(P>0.05).Compared with the control group,diet supplemented with eucalyptus oil significantly decreased the relative abundances of Methanobrevibacter ruminantium and unclassified Methanobrevibacter(P<0.05),and significantly increased the relative abundance of Methanobrevibacter euryarchaeote(P<0.05);diet supplemented with anise oil significantly decreased the relative abundance of Methanobrevibacter ruminantium(P<0.05),and significantly increased the relative abundances of the unclassified Methanobrevibacter and Methanobrevibacter euryarchaeote(P<0.05).In conclusion,the supplementation of 500 mg/(head·d)eucalyptus oil or anise oil in diets of mutton sheep has no significant effect on the rumen microbial number,but affects the rumen methanogens community.The numerical decrease of anise oil on CH_(4) production may be due to the decrease in the number of Methanobrevibacter ruminantium.