摘要
为研究日粮粗蛋白质水平(crude protein,CP)对育肥湖羊瘤胃微生物、pH及VFA含量的影响,选取54只4月龄[(32.25±2.50)kg]湖羊公羔,采用完全随机分组设计,将试验羊分为3个处理组,每个处理组18个重复,每个重复1只羊,3个处理组日粮CP水平分别为11.5%、14.0%、16.5%,试验期共70 d,包括7 d预试期,63 d正试期。试验期结束后,每组选择10只试验羊进行屠宰,测定屠宰性能并采集瘤胃内容物,用于瘤胃微生物DNA提取。结果表明:1)不同CP处理组对宰前活重、胴体重、屠宰率、瘤胃总重、瘤胃组织重及尾脂重无显著影响(P>0.05)。2)11.5%CP组瘤胃液氨态氮显著低于14.0%CP及16.5%CP组(P<0.001),但14.0%CP组与16.5%CP组无显著差异(P>0.05)。瘤胃液pH随日粮蛋白水平的增加有增加的趋势(P<0.1)。3)总挥发性脂肪酸(total volatile fatty acids,TVFA)浓度不受日粮中CP水平的影响(P>0.05),其中乙酸、丙酸、异丁酸、丁酸、戊酸比例均不受CP水平的影响(P>0.05),但异戊酸的比例随日粮中CP水平的增加有增加趋势(P=0.098)。4)在不同CP处理组中,瘤胃内溶纤维丁酸弧菌含量最高,但各处理组间无显著差异(P>0.05),其中白色瘤胃球菌、产琥珀酸丝状杆菌、普雷沃氏菌的含量均不受CP水平的影响(P>0.05),而黄色瘤胃球菌11.5%CP组显著低于14.0%CP组(P<0.05),16.5%CP组与11.5%CP组及14.0%CP组无显著差异。综上所述,日粮不同CP水平不影响试验羊屠宰性能,但能够影响瘤胃液pH及氨态氮含量,随CP水平的增加,异戊酸的比例有增加的趋势,14.0%CP组黄色瘤胃球菌数最多。
The objective of this study was to evaluate the effects of dietary CP levels on the rumen and its contents,pH,and microbial and volatile fatty acid(VFA)concentrations in finishing Hu lambs.A total of 54 three month old male Hu lambs[(32.25±2.50 kg)]were randomly divided into three groups based on their weights.The dietary CP levels were 11.5%,14%,and 16.5%,respectively.Each group contained 18 replicates,and a replicate consisted of one lamb.The pre-test period was 7 days,and the formal experiment lasted 63 days.A total of 10 lambs were selected for slaughter in each group at the end of the test period.Then,the slaughter performance was measured and the rumen contents were collected so that the rumen microbial DNA could be extracted.The results showed that 1)the different CP treatments had no significant effect on live weight before slaughter,carcass weight,slaughter rate,the total weight of the rumen,rumen tissue weight,and tail fat weight;2)the ammonia nitrogen in the rumen fluid of the 11.5%CP group was significantly lower than in the rumen fluid of the 14.0%CP and 16.5%CP groups(P<0.001),but there was no significant difference between the 14.0%CP group and the 16.5%CP group(P>0.05).Rumen pH increased as dietary protein levels rose(P<0.1).3)The TVFA concentration,and the acetate,propionate,isobutyrate,butyrate,and valerate ratios were not affected by the CP level(P>0.05).However,the isovalerate ratio tended to increase(P=0.098)as the CP level in the diet rose.4)Butyrivibrio fibrisolvens levels in the rumens from the different treatment groups were higher than the other bacteria,but there were no significant differences among the treatment groups(P>0.05).The Ruminococcus albus,Fibrobacter succinogenes,and Prevotella brevis contents were not affected by CP level(P>0.05),whereas the Ruminococcus flavefaciens levels were significantly lower in the 11.5%CP group than in the 14.0%CP group(P<0.05).The 16.5%CP group was not significantly different from 11.5%CP and 14.0%CP groups.These results indicated that the different CP levels did not affect the slaughter performance of the Hu lambs,but could affect the pH and ammonia nitrogen content of the rumen fluid.Furthermore,the isovalerate proportion increased as the CP levels rose,and the Ruminococcus flavefaciens levels were highest in the 14.0%CP group.
作者
牛骁麟
郭涛
周文静
郭龙
李飞
李发弟
NIU Xiaolin;GUO Tao;ZHOU Wenjing;GUO Long;LI Fei;LI Fadi(State Key Laboratory of Grassland Agro-ecosystems/Key Laboratory of Grassland Livestock Industry Innovation,Ministry of Agriculture and Rural Affairs/College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,Gansu,China;Engineering Laboratory of Mutton Sheep Breeding and Reproduction Biotechnology in Gansu Province,Minqin 733300,Gansu,China)
出处
《草业科学》
CAS
CSCD
2020年第5期975-983,共9页
Pratacultural Science
基金
国家重点研发计划(2018YFD0502103)
公益性行业(农业)科研专项-北方农作物秸秆饲用化利用技术研究与示范(201503134)
甘肃现代农业(草食畜)产业技术体系(GARS-09)。
