Normanton Heidi, Houdijk Jos G M, Jessop Neil S, Knox Dave P, Kyriazakis Ilias
Animal Nutrition and Health Department, SAC, Edinburgh, UK.
Br J Nutr. 2007 Jan;97(1):104-10. doi: 10.1017/S0007114507205781.
Lactating rats experience a breakdown of immunity to parasites, i.e. they carry larger worm burdens after re-infection compared to their non-lactating counterparts. Feeding high-protein foods to lactating rats results in reduced worm burdens. This could be attributed to changes in gastrointestinal environment or to overcoming effects of nutrient scarcity on host immunity. The latter hypothesis was addressed through a manipulation of nutrient demand by manipulating litter size. Twenty-three rats were immunized prior to mating and re-infected on day 2 of lactation with 1600 infective Nippostrongylus brasiliensis larvae. From parturition onwards, rats received ad libitum low-protein food (100 g crude protein/kg). Litter size were standardised to nine (LS9), six (LS6) or three (LS3) pups, by day 2 of lactation. After a further 10 d, LS9 and LS6 rats carried more worms than LS3 rats. However, feeding treatment did not affect concentrations of mucosal inflammatory cells. Achieved feed intake did not differ consistently between the treatment groups. However, LS9 and LS6 rats lost weight, whilst LS3 rats gained weight during lactation. The results support the view that resistance to N. brasiliensis is sensitive to changes in nutrient demand, and the improved resistance to N. brasiliensis is likely due to effects of overcoming nutrient scarcity on host immunity.
哺乳期大鼠对寄生虫的免疫力会下降，也就是说，与非哺乳期大鼠相比，它们在再次感染后体内的蠕虫负担更重。给哺乳期大鼠喂食高蛋白食物会降低蠕虫负担。这可能归因于胃肠道环境的变化，或者是克服了营养缺乏对宿主免疫力的影响。后一种假设是通过控制窝仔数来操纵营养需求来验证的。23只大鼠在交配前进行免疫，并在哺乳期第2天再次感染1600条巴西日圆线虫感染性幼虫。从分娩开始，大鼠自由采食低蛋白食物（100 g粗蛋白/kg）。在哺乳期第2天，将窝仔数标准化为9只（LS9）、6只（LS6）或3只（LS3）幼崽。再过10天后，LS9和LS6组大鼠体内的蠕虫比LS3组大鼠更多。然而，喂食处理并未影响黏膜炎症细胞的浓度。各处理组的实际采食量并无一致差异。然而，LS9和LS6组大鼠体重下降，而LS3组大鼠在哺乳期体重增加。结果支持这样一种观点，即对巴西日圆线虫的抵抗力对营养需求的变化敏感，对巴西日圆线虫抵抗力的提高可能是由于克服营养缺乏对宿主免疫力产生的影响。
