Berthelot F, Beaumont C, Mompart F, Girard-Santosuosso O, Pardon P, Duchet-Suchaux M
Institut National de la Recherche Agronomique, Pathologie Infectieuse et Immunologie, Nouzilly, France.
Poult Sci. 1998 Jun;77(6):797-801. doi: 10.1093/ps/77.6.797.
Previously, we have shown differences in susceptibility to the cecal carrier state in chicks orally infected with Salmonella enteritidis (SE) at 1 wk of age for four outbred lines: L2, B13, PA12, and Y11. The egg-type line L2 was one of the most susceptible lines and presented a large variability in cecal SE colonization. The heritability (h2) of the resistance to SE colonization in ceca was estimated in L2 chickens to determine whether genetic factors might be involved in its control. In three independent trials, a total of 819 L2 chicks produced from 88 sires and 232 dams were challenged orally with SE at 1 wk of age. Each week after inoculation, the frequency of cecal colonization was estimated. When this value had fallen to 50%, all the remaining animals were killed. The extent of cecal colonization by SE was estimated directly by counting the viable organisms in organs and determining the numbers of positive ceca. Enrichment culture was used in Trials 2 and 3. The effects of trial, of room within trial, and of cage within room on the frequency of SE contaminated ceca were often significant. No significant effect of sex was observed. Estimation of h2 using the frequency of SE positive ceca was low, 0.06 +/- 0.07, when results of direct culture were considered. In contrast, when considering the frequency obtained after enrichment, the h2 was estimated at 0.20 +/- 0.12. This result suggests a genetic basis for the expression of the resistance to colonization. An experiment of selection for resistance to SE carrier state in the chicken ceca should definitively confirm the genetic origin of the resistance.
此前，我们已经表明，对于4个远交系（L2、B13、PA12和Y11）的1周龄雏鸡经口感染肠炎沙门氏菌（SE）后，盲肠携带状态的易感性存在差异。蛋用型品系L2是最易感的品系之一，盲肠SE定植存在很大变异性。在L2品系鸡中估计了盲肠对SE定植抗性的遗传力（h2），以确定遗传因素是否可能参与其控制。在三项独立试验中，对88只父本和232只母本所产的总共819只L2雏鸡在1周龄时经口用SE进行攻毒。接种后每周估计盲肠定植频率。当该值降至50%时，将所有剩余动物处死。通过计数器官中的活菌并确定阳性盲肠的数量，直接估计SE在盲肠中的定植程度。试验2和试验3中使用了增菌培养。试验、试验内房间以及房间内笼子对SE污染盲肠频率的影响通常具有显著性。未观察到性别有显著影响。当考虑直接培养结果时，使用SE阳性盲肠频率估计的h2较低，为0.06±0.07。相比之下，当考虑增菌后获得的频率时，h2估计为0.20±0.12。该结果表明对定植抗性的表达存在遗传基础。在鸡盲肠中针对SE携带状态抗性的选择试验应最终证实抗性的遗传起源。
