Screening for the effects of natural plant extracts at different pH on in vitro rumen microbial fermentation of a high-concentrate diet for beef cattle.
Screening for the effects of natural plant extracts at different pH on in vitro rumen microbial fermentation of a high-concentrate diet for beef cattle.
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筛选不同pH下天然植物提取物对肉牛高精饲料体外瘤胃微生物发酵的影响
DOI：
10.2527/2005.83112572x
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发表时间：
2005
影响因子：
3.3
通讯作者：
C. Kamel
中科院分区：
文献类型：
--
作者：
P. Cardozo;S. Calsamiglia;A. Ferret;C. Kamel
在重复的 9 x 5 x 2 因子排列处理中，以五种剂量（0、0.3、3、30 和 300 mg/L）和两种不同 pH（7.0 和 5.5）测试了六种天然植物提取物和三种次生植物代谢物，以确定它们对使用高浓度育成饲料饲喂的小母牛瘤胃液的体外微生物发酵的影响。处理物为大蒜 (GAR)、肉桂 (CIN)、丝兰 (YUC)、茴香 (ANI)、牛至 (ORE) 和辣椒 (CAP) 提取物以及纯肉桂醛 (CDH)、茴香脑 (ATL) 和丁子香酚 (EUG)。每种处理均一式三份并分两个周期进行测试。将 50 毫升瘤胃液与缓冲液的 1:1 溶液引入装有 0.5 g DM 的 10:90 饲料：浓缩饲料（15.4% CP，16.0% NDF；DM 基础）的聚丙烯管中，并在 39°C 下孵育 24 小时。收集样品以测定氨氮和 VFA 浓度。 pH 从 7.0 降低至 5.5 导致总 VFA、氨氮、支链 VFA 浓度、醋酸盐比例和醋酸盐：丙酸盐含量降低 (P < 0.05)，而丙酸盐比例升高 (P < 0.05)。除了丁酸盐的 ATL 和 CDH、乙酸盐：丙酸盐比率的 ATL 和 EUG 以及氨氮浓度的 ORE 之外，pH 和剂量之间的相互作用对于所有测量都很显着。所有植物提取物的高剂量都会降低 (P < 0.05) 总 VFA 浓度。当 pH 为 7.0 时，ATL、GAR、CAP 和 CDH 降低 (P < 0.05) 总 VFA 浓度，ANI、ORE、CIN、CAP 和 CDH 增加 (P < 0.05) 乙酸盐：丙酸盐。 CIN、GAR、CAP、CDH、ORE 和 YUC 降低（P < 0.05），EUG、ANI 和 ATL 氨氮浓度升高（P < 0.05）。当 pH 为 7.0 时，植物提取物对发酵曲线的影响不利于牛肉生产。相反，当pH为5.5时，总VFA浓度没有变化（ATL、ANI、ORE和CIN）或增加（P < 0.05）（EUG、GAR、CAP、CDH和YUC），而乙酸盐：丙酸盐（ORE、GAR、CAP、CDH和YUC）减少（P < 0.05），这有利于牛肉生产。氨 N（ATL、ANI、CIN、GAR、CAP 和 CDH）和支链 VFA（ATL、EUG、ANI、ORE、CAP 和 CDH）浓度也降低（P < 0.05），表明脱氨作用受到抑制。结果表明，植物提取物对肉牛日粮中瘤胃发酵的影响可能因瘤胃 pH 值而异。当 pH 为 5.5 时，GAR、CAP、YUC 和 CDH 改变瘤胃微生物发酵，有利于丙酸盐，丙酸盐的能量效率更高。
Six natural plant extracts and three secondary plant metabolites were tested at five doses (0, 0.3, 3, 30, and 300 mg/L) and two different pH (7.0 and 5.5) in a duplicate 9 x 5 x 2 factorial arrangement of treatments to determine their effects on in vitro microbial fermentation using ruminal fluid from heifers fed a high-concentrate finishing diet. Treatments were extracts of garlic (GAR), cinnamon (CIN), yucca (YUC), anise (ANI), oregano (ORE), and capsicum (CAP) and pure cinnamaldehyde (CDH), anethole (ATL), and eugenol (EUG). Each treatment was tested in triplicate and in two periods. Fifty milliliters of a 1:1 ruminal fluid-to-buffer solution were introduced into polypropylene tubes supplied with 0.5 g of DM of a 10:90 forage:concentrate diet (15.4% CP, 16.0% NDF; DM basis) and incubated for 24 h at 39 degrees C. Samples were collected for ammonia N and VFA concentrations. The decrease in pH from 7.0 to 5.5 resulted in lower (P < 0.05) total VFA, ammonia N, branched-chain VFA concentration, acetate proportion, and acetate:propionate, and in a higher (P < 0.05) propionate proportion. The interaction between pH and doses was significant for all measurements, except for ATL and CDH for butyrate, ATL and EUG for acetate:propionate ratio, and ORE for ammonia N concentration. The high dose of all plant extracts decreased (P < 0.05) total VFA concentrations. When pH was 7.0, ATL, GAR, CAP, and CDH decreased (P < 0.05) total VFA concentration, and ANI, ORE, CIN, CAP, and CDH increased (P < 0.05) the acetate:propionate. The CIN, GAR, CAP, CDH, ORE, and YUC decreased (P < 0.05), and EUG, ANI, and ATL increased (P < 0.05) ammonia N concentration. The effects of plant extracts on the fermentation profile when pH was 7.0 were not favorable for beef production. In contrast, when pH was 5.5, total VFA concentration did not change (ATL, ANI, ORE, and CIN) or increased (P < 0.05) (EUG, GAR, CAP, CDH, and YUC), and the acetate:propionate (ORE, GAR, CAP, CDH, and YUC) decreased (P < 0.05), which would be favorable for beef production. Ammonia N (ATL, ANI, CIN, GAR, CAP, and CDH) and branched-chain VFA (ATL, EUG, ANI, ORE, CAP, and CDH) concentrations also were decreased (P < 0.05), suggesting that deamination was inhibited. Results indicate that the effects of plant extracts on ruminal fermentation in beef cattle diets may differ depending on ruminal pH. When pH was 5.5, GAR, CAP, YUC, and CDH altered ruminal microbial fermentation in favor of propionate, which is more energetically efficient.