Malecky M, Broudiscou L P
Institut National de la Recherche Agronomique-AgroParisTech, F75005 Paris, France.
J Anim Sci. 2009 Apr;87(4):1366-73. doi: 10.2527/jas.2008-1419. Epub 2008 Dec 19.
This in vitro study evaluated the roles of diet type and redox potential in the degradation of linalool, (E)- and (Z)-beta-ocimene, alpha-phellandrene, (-)-beta-pinene, (-)-alpha-pinene, (+)-alpha-pinene, sabinene, and alpha-terpinene when incubated with rumen microflora, and it provided information on the time course of their disappearance. The 9 monoterpenes are found in the winter and spring diets of dairy goats in northwestern Mediterranean grazing systems. The diets were individually exposed to rumen microflora for 3 h in 17-mL culture tubes at a concentration of 4 microL/L. The mixed flora of the inoculum was controlled by the use of vancomycin (eliminating gram-positive bacteria) and by the energy source (starch vs. structural polysaccharides) on which rumen microflora had been grown. Redox potential was controlled by addition of L-cysteine-hydrochloride. The preliminary adaptation of microbial inoculum to a diet rich in structural carbohydrates reduced the recovery yields of (E)- and (Z)-beta-ocimene, (-)-beta-pinene, (-)-alpha-pinene, (+)-alpha-pinene, and sabinene (P<0.01), whereas vancomycin was without effect. The effect of carbohydrate source likely stems from the specific composition of the microbial community rather than from its acidogenic capacity. Reducing the culture redox potential by 50 mV reduced the recovery yields of linear and monocyclic terpenes (P<0.02), and the culture redox potential interacted with the inoculum source for (E)- and (Z)-beta-ocimene and for alpha-phellandrene. The time course of terpene disappearance was studied by exposing terpenes to a rumen microflora adapted either to starch or to fiber for 3, 6, or 24 h. The degraded fraction reached a plateau within 3 h for alpha-phellandrene and for all the isomers of beta-ocimene and pinene with the fiber-adapted microflora as well as with both inocula for alpha-terpinene. With the starch-adapted microflora, this steady state was reached for most other terpenes within 6 h of incubation. Sabinene was the only compound still disappearing after an incubation period of 6 h. Biotic and environmental variables in the rumen affected terpene degradation in a way that can alter the dietary terpene profile and possibly its influence on animal product characteristics.
本体外研究评估了日粮类型和氧化还原电位在芳樟醇、（E）-和（Z）-β-罗勒烯、α-水芹烯、（-）-β-蒎烯、（-）-α-蒎烯、（+）-α-蒎烯、桧烯和α-萜品烯与瘤胃微生物群落一起孵育时降解过程中的作用，并提供了它们消失的时间进程信息。这9种单萜存在于地中海西北部放牧系统中奶山羊的冬春日粮中。日粮分别在17 mL培养管中以4 μL/L的浓度与瘤胃微生物群落接触3小时。通过使用万古霉素（消除革兰氏阳性菌）和瘤胃微生物群落生长所依赖的能源（淀粉与结构性多糖）来控制接种物的混合菌群。通过添加盐酸L-半胱氨酸来控制氧化还原电位。微生物接种物对富含结构性碳水化合物日粮的初步适应降低了（E）-和（Z）-β-罗勒烯、（-）-β-蒎烯、（-）-α-蒎烯、（+）-α-蒎烯和桧烯的回收率（P<0.01），而万古霉素没有影响。碳水化合物来源的影响可能源于微生物群落的特定组成，而非其产酸能力。将培养的氧化还原电位降低50 mV会降低直链和单环萜烯的回收率（P<0.02），并且培养的氧化还原电位与接种物来源对（E）-和（Z）-β-罗勒烯以及α-水芹烯存在相互作用。通过将萜烯暴露于适应淀粉或纤维的瘤胃微生物群落3、6或24小时来研究萜烯消失的时间进程。对于α-水芹烯以及β-罗勒烯和蒎烯的所有异构体，在适应纤维的微生物群落以及α-萜品烯的两种接种物作用下，降解部分在3小时内达到平稳状态。对于适应淀粉的微生物群落，大多数其他萜烯在孵育6小时内达到这种稳定状态。桧烯是在孵育6小时后仍在消失的唯一化合物。瘤胃中的生物和环境变量以一种可能改变日粮萜烯谱及其对动物产品特性影响的方式影响萜烯降解。
