Norup L R, Dalgaard T S, Friggens N C, Sørensen P, Juul-Madsen H R
Department of Animal Health, Welfare and Nutrition, Faculty of Agricultural Sciences, University of Aarhus, PO Box 50, DK-8830 Tjele, Denmark.
Poult Sci. 2009 Mar;88(3):543-53. doi: 10.3382/ps.2008-00431.
This study aimed to investigate the effect of mannose-binding lectin (MBL) on infections with Escherichia coli in chickens. Initially, the basic levels of MBL in 4 different lines of layer chickens, namely ISA Brown, Lohmann Selected Leghorn, Lohmann Braun, and Hellevad, were investigated. This investigation revealed a 2-to 3-fold difference in the basic levels of MBL in serum between some of these commercial lines. Furthermore, the ontogeny of the basic level of MBL in serum of an experimental chicken line was investigated. The level of MBL was very stabile for long periods, with an elevation at 5 to 7 wk of age. Another elevation in MBL level started around 18 to 19 wk of age and stayed elevated at least until 38 wk of age. In this study, it was hypothesized that chickens with high levels of MBL (H-type) may be less prone to disease caused by E. coli infection than chickens with low levels of MBL (L-type) after attempts were made to immunosuppress the chickens by immunization with a live attenuated infectious bursal disease virus (IBDV) vaccine strain. The H-type and L-type chickens were divided into 4 groups receiving either no treatment (I-E-), E. coli alone (I-E+), IBDV alone (I+E-), or IBDV and E. coli (I+E+). Body weight gain was depressed by IBDV immunization as well as E. coli inoculation. The depression of BW gain was significantly larger in L-type chickens compared with H-type chickens. The antibody response to E. coli was significantly depressed by IBDV vaccination and antibody titers to E. coli were elevated by experimental E. coli inoculation, but only in the group not given IBDV (I-E- vs. I-E+). On d 28, T-cell responses in L-type chickens showed a lower percentage of proliferating CD4+ and CD8+ T cells compared with the H-type, regardless of treatment. In conclusion, immune reactions toward infections with E. coli differed between chickens having different basal serum MBL levels, and as such, MBL may be of importance for future selection of more robust chickens for outdoor or organic farming.
本研究旨在调查甘露糖结合凝集素（MBL）对鸡大肠杆菌感染的影响。首先，研究了4种不同品系蛋鸡（即ISA Brown、罗曼精选来航鸡、罗曼褐壳蛋鸡和海兰白鸡）中MBL的基础水平。该研究揭示了其中一些商业品系之间血清中MBL基础水平存在2至3倍的差异。此外，还研究了一个实验鸡品系血清中MBL基础水平的个体发育情况。MBL水平在很长一段时间内非常稳定，在5至7周龄时有所升高。MBL水平的另一次升高始于18至19周龄左右，并至少持续升高至38周龄。在本研究中，研究人员提出假设：在用活的减毒传染性法氏囊病病毒（IBDV）疫苗株对鸡进行免疫抑制后，MBL水平高的鸡（H型）可能比MBL水平低的鸡（L型）更不易感染由大肠杆菌引起的疾病。将H型和L型鸡分为4组，分别接受不治疗（I-E-）、单独接种大肠杆菌（I-E+）、单独接种IBDV（I+E-）或接种IBDV和大肠杆菌（I+E+）。IBDV免疫和大肠杆菌接种均会抑制体重增加。与H型鸡相比，L型鸡体重增加的抑制更为明显。IBDV疫苗接种显著抑制了对大肠杆菌的抗体反应，实验性接种大肠杆菌可提高对大肠杆菌的抗体滴度，但仅在未接种IBDV的组中（I-E-与I-E+）。在第28天，无论接受何种处理，L型鸡的T细胞反应中增殖的CD4+和CD8+T细胞百分比均低于H型鸡。总之，不同基础血清MBL水平的鸡对大肠杆菌感染的免疫反应存在差异，因此，MBL对于未来选择更健壮的鸡用于户外或有机养殖可能具有重要意义。
