Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obta...Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obtain rumen protozoa and bacteria. Two groups were designed as follows： One group was the whole bacteria which were labeled using fluorescence through removing free bacteria from rumen fluid （WFLB）; the other group was the bacteria which were labeled using fluorescence without removing free bacteria from rumen fluid （FLB）. The result indicated that the bacterial predation rates of rumen protozoa was 398.4 cells/（cell h） for the group WFLB, 230.4 cells/（cell h） for the group FLB, when the corresponding values expressed as bacteria-N, they were 2.15 pg N/（cell h） for the group WFLB, and 1.24 pg N/（cell h） for the group FLB, respectively. Extrapolating the assimilation quantity of nitrogen by ciliates on bacteria of Xuhuai goat, there were 103.2 mg N/（d capita） for the group WFLB, and 59.5 mg N/（d capita） for the group FLB, respectively. It was estimated that protein losses due to microbial recycling were 0.645 g pro/（d capita） for the group WFLB and 0.372 g pro/（d capita） for the group FLB, respectively. In addition, the fluorescence-labeled technique would be a potential assay for the determination of bacterial predation rate by rumen protozoa.展开更多
This study investigated the impacts of the degree of unsaturation （unsaturity） of long-chain fatty acids on volatile fatty acid （VFA） profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, i...This study investigated the impacts of the degree of unsaturation （unsaturity） of long-chain fatty acids on volatile fatty acid （VFA） profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, including stearic acid （C18：0, control group）, oleic acid （C18：1, n-9）, linoleic acid （C18：2, n-6）, a-linolenic acid （C18：3, n-3）, arachidonic acid （C20：4, n-6） and eicosapentaenoic acid （C20：5, n-3）, were tested. Rumen fluid from three goats fitted with ruminal fistulae was used as inoculum and the inclusion rate of long-chain fatty acid was at 3% （w/w） of substrate. Samples were taken for VFA analysis at 0, 3, 6, 9, 12, 18 and 24 h of incubation, respectively. The analysis showed that there were significant differences in the total VFA among treatments, sampling time points, and treatment×time point interactions （P〈0.01）. a-Linolenic acid had the highest total VFA （P〈0.01） among different long-chain fatty acids tested. The molar proportion of acetate in total VFA significantly differed among treatments （P〈0.01） and sampling time points （P〈0.01）, but not treatment×time point interactions （P〉0.05）. In contrast, the molar proportion of propionate did not differ among treatments during the whole incubation （P〉0.05）. However, for butyrate molar proportions, significant differences were found not only among sampling time points but also among treatments and treatment×time point interactions （P〈0.01）, with eicosapentaenoic acid having the highest value （P〈0.01）. Additionally, no statistically significant differences were found in the acetate to propionate ratios among treatments groups （P〉0.05）, even the treatments stearic acid and a-linolenic acid were numerically higher than the others. The inclusion of 3% long-chain unsaturated fatty acids differing in the degree of unsaturation brought out a significant quadratic regression relation between the total VFA concentration and the double bond number of fatty acid. In conclusion, the a-linolenic acid with 3 double bonds appeared better for improving rumen microbial fermentation and the total VFA concentration.展开更多
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 fl...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.展开更多
基金carried out under the financial support from the National Natural Science Foundation of China(30571344).
文摘Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obtain rumen protozoa and bacteria. Two groups were designed as follows： One group was the whole bacteria which were labeled using fluorescence through removing free bacteria from rumen fluid （WFLB）; the other group was the bacteria which were labeled using fluorescence without removing free bacteria from rumen fluid （FLB）. The result indicated that the bacterial predation rates of rumen protozoa was 398.4 cells/（cell h） for the group WFLB, 230.4 cells/（cell h） for the group FLB, when the corresponding values expressed as bacteria-N, they were 2.15 pg N/（cell h） for the group WFLB, and 1.24 pg N/（cell h） for the group FLB, respectively. Extrapolating the assimilation quantity of nitrogen by ciliates on bacteria of Xuhuai goat, there were 103.2 mg N/（d capita） for the group WFLB, and 59.5 mg N/（d capita） for the group FLB, respectively. It was estimated that protein losses due to microbial recycling were 0.645 g pro/（d capita） for the group WFLB and 0.372 g pro/（d capita） for the group FLB, respectively. In addition, the fluorescence-labeled technique would be a potential assay for the determination of bacterial predation rate by rumen protozoa.
基金financially supported by the Graduate Student Innovation Project of Jiangsu Province,China (KYLX15_1377)the Natural Science Foundation of Jiangsu Province,China (BK20151312)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD),China
文摘This study investigated the impacts of the degree of unsaturation （unsaturity） of long-chain fatty acids on volatile fatty acid （VFA） profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, including stearic acid （C18：0, control group）, oleic acid （C18：1, n-9）, linoleic acid （C18：2, n-6）, a-linolenic acid （C18：3, n-3）, arachidonic acid （C20：4, n-6） and eicosapentaenoic acid （C20：5, n-3）, were tested. Rumen fluid from three goats fitted with ruminal fistulae was used as inoculum and the inclusion rate of long-chain fatty acid was at 3% （w/w） of substrate. Samples were taken for VFA analysis at 0, 3, 6, 9, 12, 18 and 24 h of incubation, respectively. The analysis showed that there were significant differences in the total VFA among treatments, sampling time points, and treatment×time point interactions （P〈0.01）. a-Linolenic acid had the highest total VFA （P〈0.01） among different long-chain fatty acids tested. The molar proportion of acetate in total VFA significantly differed among treatments （P〈0.01） and sampling time points （P〈0.01）, but not treatment×time point interactions （P〉0.05）. In contrast, the molar proportion of propionate did not differ among treatments during the whole incubation （P〉0.05）. However, for butyrate molar proportions, significant differences were found not only among sampling time points but also among treatments and treatment×time point interactions （P〈0.01）, with eicosapentaenoic acid having the highest value （P〈0.01）. Additionally, no statistically significant differences were found in the acetate to propionate ratios among treatments groups （P〉0.05）, even the treatments stearic acid and a-linolenic acid were numerically higher than the others. The inclusion of 3% long-chain unsaturated fatty acids differing in the degree of unsaturation brought out a significant quadratic regression relation between the total VFA concentration and the double bond number of fatty acid. In conclusion, the a-linolenic acid with 3 double bonds appeared better for improving rumen microbial fermentation and the total VFA concentration.
基金financially supported by the Innovation Foundation for Undergraduate of Yangzhou University,China (201311117034)the Domestic Cooperative Innovation ofIndustry-University-Research(XT20140012)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘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.
