1月19日,，根據(jù)美國(guó)密歇根州立大學(xué)和美國(guó)農(nóng)業(yè)部農(nóng)業(yè)研究中心的共同研究結(jié)果，在豬食中添加抗生素成分將增強(qiáng)生豬體內(nèi)腸道微生物對(duì)抗生素藥物的抗藥性,。
有關(guān)這一研究的相關(guān)論文已經(jīng)發(fā)表在了最新一期的美國(guó)《國(guó)家科學(xué)院學(xué)報(bào)》,，該項(xiàng)研究的目的旨在幫助科學(xué)家們理解在美國(guó)農(nóng)場(chǎng)中備受爭(zhēng)議的在豬食中添加抗生素的做法將可能產(chǎn)生的影響。數(shù)十年來(lái),，美國(guó)境內(nèi)的很多農(nóng)場(chǎng)都會(huì)在他們飼養(yǎng)的牲畜飼料中添加抗生素,，不管是豬，家禽還是其它農(nóng)場(chǎng)動(dòng)物,，情況都是如此,。農(nóng)場(chǎng)主們這樣做的目的首先是防止動(dòng)物們患病，其次還可以加速牲畜的生長(zhǎng)速率并提高飼料產(chǎn)出效率,。
密歇根州立大學(xué)微生物學(xué)和分子遺傳學(xué)教授詹姆斯·提亞杰(James Tiedje)表示,，科學(xué)家們目前尚無(wú)法解釋為何抗生素的攝入會(huì)加速動(dòng)物身體的成長(zhǎng)并由此提升飼料產(chǎn)出效率,，但是他們擔(dān)心這種抗生素的添加將增強(qiáng)牲畜體內(nèi)微生物對(duì)多種存在爭(zhēng)議的抗生素藥物的抗藥性，這些抗生素藥物對(duì)于人體和動(dòng)物本身的健康存在潛在的風(fēng)險(xiǎn),。他說(shuō)：“病原體的抗生素藥物抗藥性變強(qiáng)對(duì)于全世界來(lái)說(shuō)都將是一個(gè)巨大的挑戰(zhàn),。因此了解究竟是何種機(jī)制導(dǎo)致這種增強(qiáng)效應(yīng)，以及如何去控制它是至關(guān)重要的,。”
其它研究進(jìn)展還包括：
1,、在飼料添加抗生素的豬腸道內(nèi)的微生物群落中細(xì)菌的抗藥性基因種類(lèi)和數(shù)量均出現(xiàn)了增加，但仍需進(jìn)一步的長(zhǎng)期研究,；
2,、在這些生豬體內(nèi)發(fā)現(xiàn)的一些基因是出乎意料的，通常它們和一些并未在研究中使用過(guò)的抗生素有關(guān),；
3,、在食用抗生素添加物飼料的生豬體內(nèi)，與生長(zhǎng)有關(guān)的微生物基因和微生物消耗的能量大量增加,，這可能暗示了抗生素藥物與動(dòng)物生長(zhǎng)加速以及飼料產(chǎn)出率之間存在的某種聯(lián)系,；
4、在食用抗生素添加物飼料的生豬體內(nèi),，大腸桿菌菌群數(shù)量出現(xiàn)上升,。但仍需進(jìn)一步觀察以驗(yàn)證這一結(jié)論；
美國(guó)農(nóng)業(yè)部研究人員托里·羅夫特(Torey Looft)說(shuō)：“據(jù)我們所知,，這是首次針對(duì)農(nóng)場(chǎng)飼料中抗生素的添加產(chǎn)生何種影響進(jìn)行的專門(mén)研究,。借助綜合手段觀察牲畜腸道菌群的功能及組成方面發(fā)生的變化。”(生物谷 Bioon.com)
doi:10.1073/pnas.1120238109
PMC:
PMID:
In-feed antibiotic effects on the swine intestinal microbiome
Torey Looft, Timothy A. Johnson, Heather K. Allen, Darrell O. Bayles, David P. Alt, Robert D. Stedtfeld, Woo Jun Sul, Tiffany M. Stedtfeld, Benli Chai, James R. Cole, Syed A. Hashsham, James M. Tiedje, and Thad B. Stanton
Antibiotics have been administered to agricultural animals for disease treatment, disease prevention, and growth promotion for over 50 y. The impact of such antibiotic use on the treatment of human diseases is hotly debated. We raised pigs in a highly controlled environment, with one portion of the littermates receiving a diet containing performance-enhancing antibiotics [chlortetracycline, sulfamethazine, and penicillin (known as ASP250)] and the other portion receiving the same diet but without the antibiotics. We used phylogenetic, metagenomic, and quantitative PCR-based approaches to address the impact of antibiotics on the swine gut microbiota. Bacterial phylotypes shifted after 14 d of antibiotic treatment, with the medicated pigs showing an increase in Proteobacteria (1–11%) compared with nonmedicated pigs at the same time point. This shift was driven by an increase in Escherichia coli populations. Analysis of the metagenomes showed that microbial functional genes relating to energy production and conversion were increased in the antibiotic-fed pigs. The results also indicate that antibiotic resistance genes increased in abundance and diversity in the medicated swine microbiome despite a high background of resistance genes in nonmedicated swine. Some enriched genes, such as aminoglycoside O-phosphotransferases, confer resistance to antibiotics that were not administered in this study, demonstrating the potential for indirect selection of resistance to classes of antibiotics not fed. The collateral effects of feeding subtherapeutic doses of antibiotics to agricultural animals are apparent and must be considered in cost-benefit analyses.
