The effects of the unsaturated degree of long-chain fatty acids on the rumen microbial protein content and the activities of transaminases and dehydrogenase in vitro

• Published in: Journal of Integrative Agriculture Vol. 15; no. 2; pp. 424 - 431
• Main Author: GAO Jian, JING Yu-jia, WANG Meng-zhi, SHI Liang-feng, LIU Shi-min (Biotechnology Research Institute, Chinese Academy of Agricultural Sciences/National Key Facility for Gene Resources and Gene Improvement, Beijing 100081, P.R.China Zhangjiakou Academy of Agricultural Sciences, Zhangjiakou 075000, P.R.China)
• Format: Journal Article
• Language: English
• Published: Science Press 01.02.2016; College of Animal Science and Technology,Yangzhou University,Yangzhou 225009,P.R.China%Institute of Agriculture,The University of Western Australia,Crawley WA 6009,Australia; Elsevier
• Subjects: goats; long-chain fatty acid; long-chain fatty acid rumen microbes goats protein concentration; protein concentration; rumen microbes; 二十碳五烯酸; 体外; 瘤胃微生物蛋白; 脱氢酶活性; 蛋白质含量; 谷丙转氨酶; 长链脂肪酸; 饱和程度; protein concentration; rumen microbes; long-chain fatty acid; goats
• ISSN: 2095-3119; 2352-3425
• DOI: 10.1016/S2095-3119(15)61081-4

This study investigated the effects of the degree of unsaturation（unsaturity） of long-chain fatty acids on microbial protein content and the activities of transaminases and dehydrogenase in vitro using goat rumen fluid as the cultural medium.Six types of fatty acids,stearic acid（C18：0,group A,control group）,oleic acid（C18：1,n-9,group B）,linoleic acid（C18：2,n-6,group C）,α-linolenic acid（C18：3,n-3,group D）,arachidonic acid（C20：4,n-6,group E）,and eicosapentaenoic acid（C20：5,n-3,group F）,were tested,and the inclusion ratio of each fatty acid was 3%（w/w） in total of culture substrate.Samples were taken at 0,3,6,9,12,18 and 24 h,respectively,during culture for analyses.Compared with stearic acid,linoleic acid,a-linolenic acid,and arachidonic acid increased the bacterial protein content,while oleic acid and eicosapentaenoic acid had no significant effects;the protozoal protein content was reduced for all the unsaturated fatty acids,and the magnitude of the reduction appeared to be associated with the degree of unsaturity of fatty acids.The total microbial protein content was dominantly accounted by the protozoal protein content（about 4-9 folds of the bacterial protein）,and only increased by linoleic acid,but reduced by oleic acid,arachidonic acid and eicosapentaenoic acid.There were no significant effects in the activities of both glutamic oxaloacetic transaminase（GOT） and glutamic-pyruvic transaminase（GPT） for all the other fatty acids,except for arachidonic acid which enhanced GOT activity and oleic acid which enhanced GPT activity.The total dehydrogenase activity was positively correlated with the degree of unsaturation of fatty acids.In conclusion,the inclusion of 3%of long-chain unsaturated fatty acids increased bacterial protein content,whereas reduced protozoal protein content and enhanced dehydrogenase activity.The fatty acids with more than three double bonds had detrimental effects on the microbial protein content.This work demonstrates for the first time the effect rule of the unsaturation degree of long-chain fatty acids on the rumen microbial protein in vitro.