摘要
本试验旨在利用体外产气法评价缓释尿素替代山羊饲粮中苜蓿蛋白的可行性,为开发利用缓释尿素作为反刍动物蛋白质饲料提供基础数据。以4只肉羊作为瘤胃液供体羊,应用ANKOM RFS产气测量系统进行体外产气,体外发酵底物分别为含48%苜蓿不含缓释尿素的饲粮(对照组)、含24%苜蓿和0.5%缓释尿素的饲粮(试验1组)、不含苜蓿含1.0%缓释尿素的饲粮(试验2组),持续发酵72 h后终止发酵,测定指标包括产气量、发酵参数、纤维素酶活性、体外干物质降解率、挥发性脂肪酸浓度和甲烷产量。结果显示:1)试验1组和试验2组的24 h累积产气量(GP 24)、48 h累积产气量(GP 48)、72 h累积产气量(GP 72)、慢速降解部分产气量(b)、潜在产气量(a+b)、可消化有机物含量、代谢能均显著高于对照组(P<0.05)。试验1组的快速降解部分产气量(a)显著低于对照组、试验2组(P<0.05)。试验1组、试验2组、对照组的产气速率(c)数值依次降低,且各组间差异显著(P<0.05)。2)对照组、试验2组、试验1组pH依次降低且互相之间差异显著(P<0.05),但数值差异极小;试验1组的氨态氮浓度显著低于对照组和试验2组(P<0.05);3组的微生物蛋白浓度、纤维素酶活性、体外干物质降解率差异不显著(P>0.05)。3)试验1组和试验2组的丙酸浓度显著高于对照组(P<0.05);对照组、试验1组、试验2组的乙酸/丙酸依次降低且互相之间差异显著(P<0.05);3组的总挥发性脂肪酸、乙酸、丁酸浓度与甲烷产量差异不显著(P>0.05)。由此可见,在体外发酵条件下,适宜水平的缓释尿素可替代苜蓿蛋白,有利于瘤胃体外发酵。在本试验条件下,以0.5%的缓释尿素替代50%的苜蓿蛋白(饲粮中苜蓿占比由48%降至24%)为宜。
This study was conducted to evaluate the feasibility of replacing dietary alfalfa protein with slow-release urea using in vitro gas production technique for goats,and then to provide an understanding of exploitation of slow-release urea used as protein feed for ruminants.Four goats were used as rumen fluid donors.The ANKOM RFS gas production measurement system was used to gas production collection.Fermentation substrates were 3 diets:control group,the diet contained 48%alfalfa without slow-release urea;test group 1,the diet contained 0.5%slow-release urea and 24%alfalfa;test group 2,the diet contained 1.0%slow-release urea without alfalfa.The in vitro fermentation was terminated after 72 h,and the gas production,fermentation parameters,cellulase activities,in vitro dry matter degradation rate,and volatile fatty acid concentrations and methane production were measured.The results are showed as follows:1)test group 1 and test group 2 had significantly higher cumulative gas production of 24,48 and 72 h(GP 24,GP 48 and GP 72),gas production from slowly degradable fraction(b),potential gas production(a+b),digestible organic matter content,and metabolizable energy than those of control group(P<0.05).Test group 1 showed significantly lower gas production from rapidly degradable fraction(a)than that of control group and test group 2(P<0.05).The gas production rate(c)of test group 1,test group 2 and control decreased successively,and the difference was significant among all groups(P<0.05).2)The pH of control group,test group 2 and test group 1 decreased successively,and was significantly different from each other(P<0.05),but the difference of values was quite small.The concentration of ammonia nitrogen(NH 3-N)of test group 1 was significantly lower than that of control group and test group 2(P<0.05).There were no differences in microprotein concentration,cellulase activities,and in vitro dry matter degradation rate among 3 groups(P>0.05).3)The propionate concentration of test group 1 and test group 2 was significantly higher than that of control group(P<0.05).Acetate/propionate of control group,test group 1 and test group 2 decreased successively and was significantly different from each other(P<0.05).The concentrations of total volatile fatty acids,acetate,propionate,and methane production were not significantly affected among 3 groups(P>0.05).In conclusion,it is found that an appropriate level of slow-release urea is able to replace dietary alfalfa protein,which is beneficial to in vitro rumen fermentation.Under the experimental conditions,it is recommended to replace 50%alfalfa protein with 0.5%slow-release urea in the diet,and the proportion of alfalfa in the diet decreased from 48%to 24%.
作者
安靖
杨艺
吴文旋
周传社
陈鑫珠
王翀
茅慧玲
朱雯
AN Jing;YANG Yi;WU Wenxuan;ZHOU Chuanshe;CHEN Xinzhu;WANG Chong;MAO Huiling;ZHU Wen(Key Lab of Animal Genetics,Breeding and Reproduction in the Plateau Mountainous Region of Education Ministry,Institute of Animal Nutrition and Feed Science,College of Animal Science,Guizhou University,Guiyang 550025,China;Key Lab of Plateau Mountain Livestock Pollution Control and Resource Reuse Technology of Guizhou Province,Institute of New Rural Development,Guizhou University,Guiyang 550025,China;Key Lab of Agro-Ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Science,Changsha 410125,China;Institute of Animal Husbandry and Veterinary Medicine,Fujian Academy of Agricultural Sciences,Fuzhou 350013,China;College of Animal Science and Technology&College of Veterinary Medicine,Zhejiang A&F University,Hangzhou 311300,China;College of Animal Science,Anhui Agricultural University,Hefei 230036,China)
出处
《动物营养学报》
CAS
CSCD
北大核心
2023年第10期6516-6525,共10页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
国家自然科学基金项目(31960674,U20A2057)
贵州省农业科技支撑计划项目(黔科合支撑[2022]一般127)。
关键词
缓释尿素
苜蓿
体外产气法
瘤胃发酵参数
山羊
slow-release urea
alfalfa protein
in vitro gas production technique
rumen fermentation parameters
goats
