戶外放養(yǎng)的豬總是比圈養(yǎng)和嚴(yán)密隔離飼養(yǎng)的豬看起來“臟”,。但英國一項(xiàng)研究顯示,，這些戶外放養(yǎng)的“臟”小豬實(shí)際上更健康。
英國阿伯丁大學(xué)等機(jī)構(gòu)研究人員日前在《BMC生物學(xué)》期刊上報(bào)道了這一發(fā)現(xiàn),。他們將54只基因譜系近似的小豬平均分成3組,，一組在戶外放養(yǎng)，另一組在室內(nèi)圈養(yǎng),，最后一組不僅在嚴(yán)格隔離的環(huán)境下飼養(yǎng),，還被定時(shí)喂食抗生素。
研究人員分別在實(shí)驗(yàn)初期、小豬斷奶期和接近成熟期對它們進(jìn)行了分析,。結(jié)果發(fā)現(xiàn),，在戶外放養(yǎng)的那一組小豬中，腸道里約90％的細(xì)菌都屬于壁厚菌門,，這類細(xì)菌的大部分都對健康有益，有助于控制大腸桿菌和沙門氏菌等致病菌,；而室內(nèi)圈養(yǎng)的小豬腸道內(nèi)這種細(xì)菌只占70％,，隔離飼養(yǎng)的小豬腸道內(nèi)這種細(xì)菌僅為50％左右。
研究人員說,，腸道菌群的差異甚至還引起與免疫系統(tǒng)相關(guān)的基因變化,，在隔離飼養(yǎng)的小豬體內(nèi)，與發(fā)炎免疫反應(yīng)有關(guān)的基因表達(dá)更多,；而在戶外放養(yǎng)的小豬體內(nèi),，與免疫細(xì)胞T細(xì)胞相關(guān)的基因表達(dá)更多。
研究人員認(rèn)為,，實(shí)驗(yàn)表明,，看起來“臟”的環(huán)境反而更有利于小豬的健康和免疫系統(tǒng)發(fā)展。研究人員說,，雖然在小豬身上得到的實(shí)驗(yàn)結(jié)果不能直接套用到人身上,，但兩者腸道內(nèi)微生物的相似性，使得這一結(jié)果對人類也具有參考價(jià)值,。（生物谷Bioon.com）
小型豬是生物醫(yī)學(xué)研究中應(yīng)用最為廣泛的非嚙齒類大型實(shí)驗(yàn)動(dòng)物之一,，具有其它實(shí)驗(yàn)動(dòng)物不可替代的優(yōu)越性，而且作為異種器官移植最可能的供體成為研究熱點(diǎn),，因此小型豬的研究和開發(fā)利用受到生物醫(yī)藥界的普遍關(guān)注,。
“2010年廣州-東莞首屆國際小型豬論壇”將于2010年1月8日在廣州召開，詳情點(diǎn)擊：http://www.minipig.org/
生物谷推薦原始出處：
BMC Biology 2009, 7:79doi:10.1186/1741-7007-7-79
Environmentally-acquired bacteria influence microbial diversity and natural innate immune responses at gut surfaces
Imke E Mulder* 1 , Bettina Schmidt* 1 , Christopher R Stokes2 , Marie Lewis2 , Mick Bailey2 , Rustam I Aminov1 , James I Prosser3 , Bhupinder P Gill4 , John R Pluske5 , Claus-Dieter Mayer6 , Corran C Musk1 and Denise Kelly1
1Gut Immunology Group, University of Aberdeen, Rowett Institute of Nutrition and Health, Greenburn Road, Aberdeen AB21 9SB, UK
2Veterinary Pathology, Infection & Immunity, Langford House, Langford, Bristol, BS40 5DU, UK
3Institute of Biological and Environmental Sciences, University of Aberdeen, St Machar Drive, Aberdeen AB24 3UU, UK
4Agricultural and Horticultural Development Board, Winterhill House, Snowdon Drive, Milton Keynes MK6 1AX, UK
5School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA 6150, Australia
6Biomathematics & Statistics Scotland, University of Aberdeen, Rowett Institute of Nutrition and Health, Greenburn Road, Aberdeen AB21 9SB, UK
Background
Early microbial colonization of the gut reduces the incidence of infectious, inflammatory and autoimmune diseases. Recent population studies reveal that childhood hygiene is a significant risk factor for development of inflammatory bowel disease, thereby reinforcing the hygiene hypothesis and the potential importance of microbial colonization during early life. The extent to which early-life environment impacts on microbial diversity of the adult gut and subsequent immune processes has not been comprehensively investigated thus far. We addressed this important question using the pig as a model to evaluate the impact of early-life environment on microbe/host gut interactions during development.
Results
Genetically-related piglets were housed in either indoor or outdoor environments or in experimental isolators. Analysis of over 3,000 16S rRNA sequences revealed major differences in mucosa-adherent microbial diversity in the ileum of adult pigs attributable to differences in early-life environment. Pigs housed in a natural outdoor environment showed a dominance of Firmicutes, in particular Lactobacillus, whereas animals housed in a hygienic indoor environment had reduced Lactobacillus and higher numbers of potentially pathogenic phylotypes. Our analysis revealed a strong negative correlation between the abundance of Firmicutes and pathogenic bacterial populations in the gut. These differences were exaggerated in animals housed in experimental isolators. Affymetrix microarray technology and Real-time Polymerase Chain Reaction revealed significant gut-specific gene responses also related to early-life environment. Significantly, indoor-housed pigs displayed increased expression of Type 1 interferon genes, Major Histocompatibility Complex class I and several chemokines. Gene Ontology and pathway analysis further confirmed these results.
Conclusion
Early-life environment significantly affects both microbial composition of the adult gut and mucosal innate immune function. We observed that a microbiota dominated by lactobacilli may function to maintain mucosal immune homeostasis and limit pathogen colonization.
