Liver abscesses occur in finishing cattle fed high-grain, low-roughage diets. Cattle with abscessed livers do not show any clinical signs and are detected only at slaughter. Liver abscesses, which account for 67% of all liver abnormalities in cattle slaughtered in the United States, are of major economic concern to the beef industry. Fusobacterium necrophorum, Trueperella pyogenes, and Salmonella enterica, particularly the serotype Lubbock, are the main etiologic agents. Currently, the control of liver abscesses is based on in-feed use of antibiotics. The emergence and dissemination of antimicrobial resistance to antibiotics use in animals is a public health concern. Plant-based phenolic compounds, called phytophenols, are known to have antimicrobial properties. Our objectives were to evaluate antimicrobial activities of phytophenols on the liver abscess bacterial pathogens. Phytophenols extracted from rosemary, green tea, grapeseed, organic goji berry, and green coffee were selected for testing. The phytophenols were extracted using 75% aqueous acetone and total phenolic content was determined by a spectrophotometric analysis. Bacteria were cultured in Mueller-Hinton broth (S. Lubbock and T. pyogenes) or anaerobic brain-heart infusion broth (F. necrophorum with and without phytophenols, at 6, 12, 24, and 48 hours and bacterial concentrations were determined. If phytophenol was inhibitory, a micro-broth dilution method was used to quantify the inhibition. Phytophenols from green tea, grape seed, and rosemary inhibited T. pyogenes. Further studies are ongoing to investigate different concentrations of phenolic compounds on the pathogens. Phytophenols that inhibit the pathogens may have the potential to be used as feed additives to prevent liver abscesses.

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48 评估植物酚对导致饲养场牛肝脓肿的细菌病原体的抗菌活性

肝脓肿发生在喂食高谷物、低粗饲料的牛的育肥过程中。肝脏脓肿的牛没有任何临床症状，仅在屠宰时才被发现。肝脓肿占美国屠宰牛的所有肝脏异常的 67%，是牛肉行业的主要经济问题。坏死梭杆菌、化脓性Trueperella 和肠沙门氏菌，特别是血清型Lubbock，是主要的病原体。目前，肝脓肿的控制是基于饲料中抗生素的使用。抗生素耐药性在动物身上的出现和传播是一个公共卫生问题。众所周知，植物酚类化合物（称为植物酚）具有抗菌特性。我们的目标是评估植物酚对肝脓肿细菌病原体的抗菌活性。选择从迷迭香、绿茶、葡萄籽、有机枸杞和绿咖啡中提取的植物酚进行测试。使用 75% 含水丙酮提取植物酚，并通过分光光度分析确定总酚含量。在 Mueller-Hinton 肉汤（S. Lubbock 和 T. pyogenes）或厌氧脑心浸液肉汤（含有和不含植物酚的 F. necrophorum 培养基中培养 6、12、24 和 48 小时，并测定细菌浓度。如果植物酚具有抑制作用，采用微量肉汤稀释法对抑制进行量化。绿茶、葡萄籽和迷迭香中的植物酚抑制化脓性杆菌。正在进行进一步的研究以研究病原体上不同浓度的酚类化合物。抑制病原体的植物酚有可能被用作饲料添加剂以预防肝脓肿。