摘要
本试验旨在揭示不同添加量、不同种类的中链脂肪酸对50∶50精粗比饲粮体外瘤胃发酵的影响,为中链脂肪酸种类及添加量的选择及后续的相关研究提供理论依据。试验采用体外产气法,采用单因素试验设计,以全价混合日粮(TMR,精粗比50∶50)为发酵底物,在体外瘤胃液(取自延边黄牛)中分别添加0 (对照组)、0.2%、0.8%、1.2%、2.0%(干物质基础)的辛酸(C_(8))、癸酸(C_(10))和月桂酸(C_(12))。每个中链脂肪酸5个组(CON组、T1组、T2组、T3组和T4组),每组3个平行。研究它们对肉牛体外瘤胃发酵产气量、产气参数、甲烷产量、瘤胃原虫数量、发酵参数、体外营养物质表观消化率等的影响。结果表明:1)各时间点辛酸和癸酸各试验组的产气量与对照组相比均无显著差异(P>0.05);月桂酸T2~T4组产气量从24 h开始与对照组相比显著降低(P<0.05),且随着月桂酸添加量的增加,产气量在24、36 h呈先降低后升高的二次曲线变化(P<0.05)。2)随着3种中链脂肪酸添加量的增加,甲烷产量和瘤胃原虫数量均呈线性下降(P<0.05),其中辛酸T3、T4组瘤胃原虫数量显著低于对照组(P<0.05)。3)辛酸T4组丁酸含量随着辛酸添加量的增加呈先升高后降低的二次曲线变化(P<0.05);癸酸T2~T4组氨态氮含量与对照组相比显著降低(P<0.05),且随着癸酸添加量的增加呈线性下降趋势(P<0.05),T3、T4组乳酸含量与对照组相比显著降低(P<0.05),各组间总挥发性脂肪酸及乙酸、丙酸、丁酸含量均无显著差异(P>0.05);月桂酸T3、T4组pH、各试验组氨态氮含量及T4组丁酸含量与对照组相比显著降低(P<0.05),且随着月桂酸添加量的增加呈线性下降(P<0.05),各试验组丙酸含量与对照组相比显著升高(P<0.05),且随着月桂酸添加量的增加呈线性上升(P<0.05)。4)辛酸和癸酸各试验组有机物消化率(OMD)、代谢能(ME)值及微生物蛋白(MCP)产量与对照组相比均无显著差异(P>0.05);月桂酸各试验组OMD、ME值及MCP产量与对照组相比显著降低(P<0.05)。5)辛酸、癸酸和月桂酸各试验组的粗蛋白质体外消化率(IVCPD)与对照组相比显著降低(P<0.05)。由此可见,在本试验条件下,不同种类及添加量的中链脂肪酸对瘤胃液体外发酵参数均有一定程度的改善,且与添加量有关。
This experiment was conducted to investigate the effects of different dosages and types of medium chain fatty acids on rumen fermentation in vitro in diet with 50∶50 concentrate to forage ratio,and to provide theoretical basis for the selection of types and dosages of medium chain fatty acids and subsequent related studies. This experiment adopted in vitro gas method,choose the single factor experiment design,used total mixed ration(concentrate to roughage ratio was 50:50)as fermentation substrate,and in vitro rumen fluid(from Yanbian cattle)was supplemented with 0(control group),0.2%,0.8%,1.2%,2.0%(dry matter basis)octanoic acid(C_(8)),capric acid(C_(10))and lauric acid(C_(12)),respectively. There were 5 groups for each medium chain fatty acid(CON group,T1 group,T2 group,T3 group and T4 group),3 in parallel for each treatment. The effects on gas production,gas production parameters,methane production and the number of rumen protozoa,fermentation parameters and in vitro nutrient digestibility of beef cattle were studied. The results showed as follows:1)at each time point,there was no significant difference in gas production between octanoic acid and capric acid groups and control group(P>0.05);from 24 h,gas production in lauric acid T2 to T4 groups was significantly decreased compared with control group(P<0.05),and showed a firstly decreased and then increased quadratically change with the dosages of lauric acid increased at 24 and 36 h(P<0.05). 2)With the dosages of three kinds of medium chain fatty acids increased,methane production and the number of rumen protozoa decreased linearly(P<0.05),and the number of rumen protozoa in octanoic acid T3 and T4groups was significantly lower than that in the control group(P<0.05). 3)The content of butyric acid in octanoic acid group showed a firstly increased and then decreased quadratically change with the dosages of octanoic acid increased(P<0.05);the content of ammoniacal nitrogen(NH3-N)in capric acid T2 to T4 groups was significantly lower than that in control group(P<0.05),and showed a linearly decreased trend with the dosages of capric acid increased(P<0.05),compared with control group,the content of lactic acid in capric acid T3 and T4 groups was significantly decreased(P<0.05),but there were no significant difference in the contents of total volatile acid and acetic acid,propionic acid,butyric acid among all groups(P>0.05);pH in lauric acid T3 and T4 groups,NH3-N content in all lauric acid experimental groups and butyric acid content in lauric acid T4 group were significantly decreased compared with control group(P<0.05),and showed a linearly decreased trend with the dosages of lauric acid increased(P<0.05),propionic acid content in all experimental groups was significantly increased compared with control group(P<0.05),and showed a linearly increased trend with the dosages of lauric acid increased(P<0.05). 4)Organic matter digestibility(OMD),metabolizable energy(ME)and microbial protein(MCP)in octanoic acid and capric acid groups were no significant difference compared with the control group(P>0.05);OMD,ME and MCP in lauric acid group were significantly decreased compared with the control group(P<0.05). 5)Compared with the control group,the crude protein digestibility in vitro(IVCPD)in octanoic acid,capric acid and lauric acid groups was significantly decreased(P<0.05). In conclusion,under the conditions of this experiment,different types and dosages of medium chain fatty acids can improve rumen liquid external fermentation parameters to a certain extent,and it is related to the dosage.[Chinese Journal of Animal Nutrition,2022,34(5):3032-3045]
作者
栾嘉明
杨东旭
冯鑫
杨濛
周金影
金英海
张敏
耿春银
LUAN Jiaming;YANG Dongxu;FENG Xin;YANG Meng;ZHOU Jinying;JIN Yinghai;ZHANG Min;GENG Chunyin(College of Agriculture,Yanbian University,Yanji 133000,China;Ministry of Education,Engineering Research Center of North-East Cold Region Beef Cattle Science&Technology Innovation,Yanbian University,Yanji 133002,China)
出处
《动物营养学报》
CAS
CSCD
北大核心
2022年第5期3032-3045,共14页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
国家自然科学基金项目(32060763,31660669)
高等学校学科创新引智计划(D20034)。
关键词
体外瘤胃发酵
中链脂肪酸
产气量
甲烷
瘤胃原虫数量
in vitro rumen fermentation
medium chain fatty acids
gas production
methane
the number of rumen protozoa
