摘要
【目的】试验旨在探究不同蛋白质水平饲粮中添加过瘤胃蛋氨酸(rumen-protected methionine, RPM)对牦牛生长性能、瘤胃发酵参数及养分表观消化率的影响,以期为舍饲牦牛养殖中饲粮蛋白质水平及RPM适宜添加量提供参考。【方法】采用2×3双因素试验设计,分别设置2个蛋白质水平:低(13%)、高(15%)蛋白质水平和3个RPM水平:0、0.05%和0.10%。选取36头体重(225.29 kg±30.59 kg)、体尺接近的4岁健康公牦牛,随机分为6个处理组,每个处理组6个重复,每个重复1头牛,单栏单饲,预饲期10 d,试验期60 d。分别在试验第66~69和70天时采集饲料样、粪样和瘤胃液,用于测定牦牛的生长性能、养分表观消化率和瘤胃发酵参数指标。【结果】(1)饲粮蛋白质水平对牦牛平均日干物质采食量(average daily dry matter intake, ADMI)无显著影响(P>0.05),但相较13%蛋白质组,15%蛋白质组牦牛平均日增重(average daily gain, ADG)显著提高(P<0.05)且料重比(feed to gain ratio, F/G)显著降低(P<0.05)。RPM水平对牦牛ADMI和F/G无显著影响(P>0.05),但有增加ADG的趋势(P=0.051)。饲粮蛋白质水平及RPM水平对牦牛ADMI存在一定的交互作用(P=0.058)。(2)饲粮蛋白质水平对牦牛瘤胃pH和微生物蛋白质(microbiological proteins, MCP)含量均无显著影响(P>0.05),但有增加瘤胃氨态氮(NH_(3)^(-)N)含量的趋势(P=0.091)。饲粮RPM水平对瘤胃pH、MCP和NH_(3)^(-)N无显著影响(P>0.05)。饲粮蛋白质水平及RPM水平对牦牛瘤胃NH_(3)^(-)N含量存在一定的交互作用(P=0.092)。与13%蛋白质组相比,15%蛋白质组牦牛瘤胃丙酸含量显著升高(P<0.05),瘤胃丁酸(P=0.066)、异丁酸(P=0.073)、戊酸(P=0.053)、异戊酸(P=0.056)含量均有升高的趋势。饲粮RPM水平对牦牛瘤胃挥发性脂肪酸(volatile fatty acid, VFA)浓度无显著影响(P>0.05),饲粮蛋白质水平和RPM水平对瘤胃VFA含量无显著交互作用(P>0.05)。(3)与13%蛋白质组相比,15%蛋白质组牦牛对粗蛋白质、钙、酸性洗涤纤维的表观消化率显著提高(P<0.05)。饲粮RPM水平对牦牛养分表观消化率无显著影响(P>0.05)。饲粮蛋白质水平和饲粮RPM水平对牦牛养分表观消化率无显著交互作用(P>0.05)。【结论】本试验条件下,在4岁舍饲牦牛15%蛋白质水平饲粮中添加0.05%RPM能够改善其瘤胃发酵,提高其干物质采食量、养分表观消化率和生长性能。
【Objective】This experiment aimed to explore the effects of supplementing rumen-protected methionine(RPM)to diets with different protein levels on the growth performance,rumen fermentation and nutrient apparent digestibility of yaks,so as to provide a reference for dietary protein level and RPM supplementation of house-feeding yaks breeding.【Method】A 2×3 two-factor experimental design was adopted in this experiment.Two protein levels were low(13%)and high(15%),and three RPM levels were 0,0.05%and 0.10%.A total of thirty-six 4-year-old healthy male yaks with similar body weight(225.29 kg±30.59 kg)and body size were selected and randomly divided into six treatment groups.Each treatment group had six replicates,and each replicate had one yak.Single pen and single feeding were adopted.The pre-trial period was 10 d,followed by a formal trial period of 60 d.Samples of feed,faeces and rumen fluid were collected on 66-69 and 70 d of experiment for determining the growth performance,apparent digestibility of nutrients and rumen fermentation parameters of yaks.【Result】①Dietary protein levels had no significant effect on average daily dry matter intake(ADMI)of yaks(P>0.05),but compared with 13%protein group,average daily gain(ADG)of yaks in 15%protein group was significantly higher(P<0.05),and feed to gain ratio(F/G)was significantly lower(P<0.05).The RPM supplementation had no significant effect on ADMI and F/G(P>0.05),but tended to increase ADG(P=0.051).There was a trend of interaction between dietary protein levels and RPM levels on ADMI in yaks(P=0.058).②Dietary protein levels had no significant effect on rumen pH and microbiological proteins(MCP)(P>0.05),but had a tendency to increase the content of NH_(3)^(-)N(P=0.091).There was no significant effect of dietary RPM levels on rumen pH,MCP and NH_(3)^(-)N(P>0.05).There was a trend of interaction between dietary protein levels and RPM levels on rumen NH_(3)^(-)N content in yak(P=0.092).Compared with 13%protein group,content of propionic acid was higher(P<0.05),the content of butyric acid(P=0.066),isobutyric acid(P=0.073),valeric acid(P=0.053)and isovaleric acid(P=0.056)had a tendency to increase in 15%protein group.There was no significant effect of dietary RPM levels on rumen volatile fatty acids(P>0.05).There was no significant interaction to volatile fatty acid between dietary protein levels and RPM levels(P>0.05).③Compared with 13%protein group,apparent digestibility of crude protein,calcium and acid detergent fiber in 15%protein group was significantly increased(P<0.05).There was no significant effect of dietary RPM levels on nutrient apparent digestibility(P>0.05).There was no significant interaction to nutrients apparent digestibility between dietary protein levels and dietary RPM levels(P>0.05).【Conclusion】Under the conditions of this experiment,adding 0.05%rumen protected methionine to the diet with a 15%protein level for 4-year-old house-fed yaks could improve their rumen fermentation,increase their dry matter intake,nutrient apparent digestibility and growth performance.
作者
赖秋爽
黎凌铄
李姝熠
田维
余青婷
张康林
李德鹏
刘骏
姜菲
彭忠利
吴建平
黄艳玲
LAI Qiushuang;LI Lingshuo;LI Shuyi;TIAN Wei;YU Qingting;ZHANG Kanglin;LI Depeng;LIU Jun;JIANG Fei;PENG Zhongli;WU Jianping;HUANG Yanling(College of Animal Science and Veterinary Medicine of Southwest Minzu University,Chengdu 610041,China;Institute of Animal Husbandry Scienc,Ganzi Tibetan Autonomous Prefecture,Kangding 626000,China)
出处
《中国畜牧兽医》
北大核心
2025年第4期1567-1578,共12页
China Animal Husbandry & Veterinary Medicine
基金
四川肉牛创新团队建设项目(sccxtd-2024-13)
油菜秸秆饲料化高效利用技术研究与应用(2022YFN0063)
牦牛高效养殖关键技术与集成应用研究(280130033501)。
关键词
牦牛
蛋白质水平
过瘤胃蛋氨酸
生长性能
瘤胃发酵
养分表观消化率
yak
protein level
rumen-protected methionine
growth performance
rumen fermentation
nutrient apparent digestibility
