Houdijk J G M
Animal Nutrition and Health Department, Scottish Agricultural College, Edinburgh, UK.
Parasite Immunol. 2008 Feb;30(2):113-21. doi: 10.1111/j.1365-3024.2008.00992.x.
Periparturient relaxation of immunity (PPRI) to gastrointestinal nematode parasites may have a nutritional basis, as the increasing nutrient demand at times of nutrient scarcity during late pregnancy and subsequent lactation may result in a penalty on expression of acquired immunity to parasites. This nutritional basis implies that lowering nutritional demand, at constant nutrient supply, should reduce the degree of PPRI. Evidence to support the latter is reviewed through exploration of the effects of reproductive effort on periparturient resistance to parasites. A large body of evidence shows that a lower nutritional demand arising from rearing single rather than multiple lambs and/or kids consistently reduces the degree of PPRI in small ruminants, as manifested by reduced worm burdens and/or nematode egg excretions. Such variation in reproductive effort may also account, at least to some extent, for the often observed between-breed differences in PPRI, which may arise from differences in production potential, and thus nutritional demand. A reduction in nutrient demand can reduce the degree of PPRI in a matter of days. However, host immune responses associated with this nutritional sensitivity of host resistance remain to be elucidated, which may be achieved through a recently established periparturient rodent model.
围产期对胃肠道线虫寄生虫的免疫放松（PPRI）可能有营养基础，因为在妊娠后期和随后的哺乳期营养稀缺时营养需求增加，可能会对寄生虫获得性免疫的表达造成不利影响。这种营养基础意味着，在营养供应恒定的情况下，降低营养需求应能减轻PPRI的程度。通过探讨繁殖力对围产期寄生虫抵抗力的影响，对支持后者的证据进行了综述。大量证据表明，饲养单只而非多只羔羊和/或幼崽所产生的较低营养需求，持续降低了小型反刍动物的PPRI程度，表现为蠕虫负荷降低和/或线虫卵排泄减少。繁殖力的这种差异也可能至少在一定程度上解释了PPRI中经常观察到的品种间差异，这种差异可能源于生产潜力的不同，进而导致营养需求的差异。营养需求的降低可在数天内减轻PPRI的程度。然而，与宿主抵抗力的这种营养敏感性相关的宿主免疫反应仍有待阐明，这可能通过最近建立的围产期啮齿动物模型来实现。
