| Conjugated linoleic acids (CLA) represent a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bonds, and subsequent work has found that positive health effects associated with dietary CLA included reduction in body fat accretion, modulation of the immune system, antiatherosclerosis, anticarcinogenesis, and enhanced bone mineralization. The CLA found in milk and meat fat of ruminants originate from two sources. One source is CLA formed during ruminal biohydrogenation of linoleic acid. The second source is CLA synthesized by the animal’s tissues from trans-11C18:1, another intermediate in the biohydrogenation of unsaturated fatty acids. Thus, mechinism and regulation of CLA in food products produced by ruminants interested ruminant physiologist and nutritionist. In this study, dairy cows were served as experimetal animals to investigate the effect of ricinoleic acid, extract of Chrysanthemum coronarium L. and their combination on digestion and metabolism of rumen, and TVA and CLA production in the rumen, and also on concentration of some other fatty acids in rumen.1. Effect of ricinoleic acid on biohydrogenation of linoleic acid in rumen of milk cowIt was reported that ricinoleic acid may reduce hydrogentaion of unsaturated fatty acids in rumen. And incubation of ruminal fluid in vitro was carried out to investigate effect of ricinoleic acid on biohydrogenation of linoleic acid in ruminal fluid. Ruminal fluid, gained from4milk cows with ruminal fistula, was incubated with ricinoleic acid and/or linoleic acid in vitro. Ruminal fluid samples were collected for analysis of pH value, ammonia nitrogen, microbe crude protein, volatile fatty aicds, and long chain fatty acids. Results showed that pH value had no significant difference between control and test group; ammonia nitrogen concentration in test group was significantly lower than that in control group after2h; microbe crude protein concentration in middle dose of ricinoleic acid treatment was signficantly higher than that in test group at6h; significant difference was not detected in long chain fatty acids between control and test group, but TVA and c9t11CLA concentration went increasingly after1h. It was suggested that ricinoleic acid had no effect on pH value of ruminal fluid, and reduced degradation of nitrogen-containing material; middle-dose ricinoleic acid could profit to de novo synthesis of protein by microbes; ricinoleic acid could reduce the biohydrogenation of linoleic acid in rumen, which could increase accumulaiton of TV A and formation of c9t11-CLA in rumen.2. Effect of Chrysanthemum coronarium L. extract on biohydrogenation of linoleic acid in rumen of milk cowBased on the reported that daisy plant could reduce biohydrogentation of unsaturated fatty acids in rumen, experiment in vitro was carried out to investigate effect of Chrysanthemum coronarium L. on biohydrogenation of linoleic acid in rumen. Ruminal fluid was gained from4milk cows with permanent ruminal fistula, then incubated with Chrysanthemum coronarium L. extract and/or linoleic acid. Samples were collected to analysis of pH value, ammonia nitrogen, microbe crude protein, VFA, and LCFA. Chrysanthemum coronarium L. extract in middle dose could reduced ammonia nitrogen significantly, and Chrysanthemum coronarium L. extract in certain concentration could reduce the degradation of nitrogen-containing material in rumen. And microbe crude protein increased significantly at6h in test group, Chrysanthemum coronarium L. extract may profit to de novo synthesis of protein by microbes. TV A and c9t11-CLA concentration in control group reached up to peak at1h, then declined, and TV A and c9tl1-CLA in test group were higher than those in control group after3h, which suggested that Chrysanthemum coronarium L. extract had inhibition on biohydrogenation in rumen, and increased accumulation of TV A and formation of c9t11-CLA.3. Combining effect of ricinoleic acid and Chrysanthemum coronarium L. extract on biohydrogenation of linoleic acid inrumen of milk cowIt was found that ricinoleci acid and Chrysanthemum coronarium L. extract could reduce biohydrogenation of unsaturated fatty acid in rumen, and ruminal fluid, gained from4milk cows was incubated with ricinoleic acid, Chrysanthemum coronarium L. extract to investigate the combining effect of ricinoleic acid and Chrysanthemum coronarium L. extract on biohydrogenation of linoleci acid in rumen. Linoleic acid was added into ruminal fluid, and sample was collected at0,1,2,3and4h for analysis of C16:0, C18:0, TVA, C18:2n6, C18:3n3, c9t11-CLA and so on. In whole incubation, C18:0concentratio in control group, but that declined after4h in test group, and TVA c9t11-CLA in test group was higher than those in control group. It suggested that ricinoleci acid and Chrysanthemum coronarium L. extract had combining effect on biohydrogenation in rumen which could reduce biohydrogenation of linoleic acid,and increase accumulation of TVA and formation of c9t11-CLA. |
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