Avian plumage harbors various pathogens such as feather-degrading bacteria, which have the potential to reduce host fitness. A growing body of evidence suggests that the secretion of the uropygial gland of birds-preen oil-acts as one of the first lines of defence against harmful bacteria. However, previous studies on the antimicrobial impact of preen oil have yielded controversial results. The impact of preen oil on bacterial densities of feathers was experimentally investigated in two passerine species: great tits Parus major and pied flycatchers Ficedula hypoleuca. More specifically, we tested whether the antibacterial effect of the preen oil secreted by the same individual differs from that of the preen oil originating from the gland of other species. In the laboratory, ventral feathers were treated with preen oil from (1) an individual's own gland, (2) from the gland of another passerine species, or (3) from the gland of a phylogenetically distant bird species. We detected a significant antibacterial effect of preen oil on bacteria that were attached to feathers, though the effect did not depend on whether the oil originated from the individual's own gland or from the gland of another bird species. However, treatment with preen oil suppressed the density of bacteria more in the pied flycatcher than in the great tit. This is the first study providing experimental evidence that preen oil represents an important antimicrobial mechanism against those plumage bacteria that are attached to feathers.

中文翻译：

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精油对雀形目鸟类羽毛细菌影响的实验研究。

禽羽毛携带着各种病原体，例如降解羽毛的细菌，它们可能会降低宿主的适应能力。越来越多的证据表明，禽类尿道腺的分泌是预防有害细菌的第一道防线之一。但是，先前对自装油的抗微生物作用的研究产生了争议性的结果。通过实验研究了两种雀形目物种中的天然油对羽毛细菌密度的影响：大山雀帕鲁斯（Parus major）和斑蝇fly Ficedula hypoleuca。更具体地说，我们测试了同一个人分泌的精油的抗菌效果是否与源自其他物种腺体的精油的抗菌效果不同。在实验室中，腹羽用（1）自己的腺体，（2）来自另一种雀形目物种的腺体，或（3）来自系统发育距离较远的鸟类的腺体。尽管该作用并不取决于该油是否来自个人的自身腺体或另一种鸟类的腺体，但我们检测到它们对附着在羽毛上的细菌具有显着的抗菌作用。但是，用天然油处理比在大山雀中更能抑制斑the中的细菌密度。这是第一项提供实验证据的实验，表明味精油对附着在羽毛上的羽毛细菌具有重要的抗菌作用。尽管该作用并不取决于该油是否来自个人的自身腺体或另一种鸟类的腺体，但我们检测到它们对附着在羽毛上的细菌具有显着的抗菌作用。但是，用天然油处理比在大山雀中更能抑制斑the中的细菌密度。这是第一项提供实验证据的实验，表明味精油对附着在羽毛上的羽毛细菌具有重要的抗菌作用。尽管该作用并不取决于该油是否来自个人的自身腺体或另一种鸟类的腺体，但我们检测到它们对附着在羽毛上的细菌具有显着的抗菌作用。但是，用天然油处理比在大山雀中更能抑制斑the中的细菌密度。这是第一项提供实验证据的实验，表明味精油对附着在羽毛上的羽毛细菌具有重要的抗菌作用。