| Adding the right amount of essential oil in the diet is an effective way to improve the concentration of unsaturated fatty acids in ruminant meat and milk products. Howere, the essential oil have some negative effect on rumen fermentation will reduce the degradation rate of fibers. Therefore, it is important to seek for the combinations that both can reduce the hydrogenation of fatty acids and promote rumen fermentation. Few Studies reported the effect of rubber seed oil on rumen fermentation and hydrogenated, and studieshave shown that Yucca schidigera is a potent regulator of rumen fermentation control agent. Therefore, the objective of this experiment was to investigate the effects of rubber seed oil(RO) or combination with Yucca schidigera(YS) on rumen fermentation parameters and fatty acids hydrogenated of in vitro. Specific content is divided into the following three parts. Experiment 1: Effect of rubber seed oil on rumen fermentation parameters and hydrogenation of fatty acidsRubber seed oil was added to total mixed ration(TMR) at the rate of 0, 1, 2, 3 and 4% dry matter of the diet. Rumen fluid was obtained from three fistulaed Holstein cows and incubated with 0.5g TMR for 0, 12 and 24 h at 39℃. Gas production(GP), fermentation kintetics, in vitro dry matter digestibility(IVDMD), neutral detergent fiber degradation(DNDF), acid detergent fiber degradation(DADF), and volatile fatty acids(VFA) were determined. The results showed as follows, rubber seed oil did not have significant effect on(P>0.05) GP24, pH, NH3-N, IVDMD, DNDF, DADF, total and individual VFAs. However, the DNDF tended to decrease linearly with increasing levels of rubber seed oil. After 24 h incubation, the concentration of C16:1, t11C18:1, t9C18:1, c9C18:1, c9c12C18:2, C18:3, c9t11 CLA, t10c12 CLA and C22:2 increased(P<0.05) with increasing levels of rubber seed oil. Thus, in vitro fermentation conditions, RO did not affect rumen fermentation and improve the concentration of t9C18:1, c9t11 CLA, t10c12 CLA. Experiment 2: Effect of Yucca schidigera on rumen fermentation parametersThe experiments were divided into two parts. In the first part, five treatments(consisted of supplemental YS at 0, 1, 5, 25 and 125 g/kg) were randomly assigned into 6 of 30 incubation bottles together with 0.5 g TMR, 50 m L basal media and 25 m L rumen fluid obtained from three rumen-cannulated lactating Holstein dairy cows. GP was continuously measured in an automated trace gas recording system(AGRS-III, Beijing) at 39℃ during 30 h of incubation. In the second part, the same as above and cultured at 39℃ shaking incubator for 30 h in vitro. Results showed that YS at 25 and 125 g/kg improved GP(P<0.05), IVDMD(P<0.05), DNDF(P<0.05) and DADF(P<0.05). YS decreased the concentration of NH3-N(P<0.05), with the increasing of YS. After 30 h incubation, the acetate propionate and TVFA increased significantly(P<0.05). Therefore, YS was beneficial to manipulate rumen fermentation in vitro. Experiment 3: Effect of rubber seed oil, the blends of rubber seed oil and Yucca schidigera on rumen fermentation parameters and hydrogenation of fatty acidsThe treatments were as follow: 1, 2, 3 and 4%DM of RO mixed with YS(12.5 mg)(IO+YS), respectively(four replicates per treatment). All treatments were evaluated in vitro 0, 12 and 24 h batch culture of 25 m L rumen fluid with 0.5 g TMR(48% forage and 52% concentrate) and 50 mL basal media. Results showed that the blends of RO and YS did not significant effect(P>0.05) GP24, pH, NH3-N, IVDMD, DNDF, DADF, FA, total and individual VFAs. The blends of RO and YS did not effect rumen fermentation and the accumulation of UFA in vitro.Therefore, RO seems to enhance the accumulation of t9C18:1, c9t11 CLA, t10c12 CLA and did not effect rumen fermentation negatively in vitro. YS was beneficial to manipulate rumen fermentation in vitro. However, the blends of RO and YS have no effect on rumen fermentation and the accumulation of UFA in vitro. |
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