DeWolf Bradley D, Bauman Cathy A, Menzies Paula I, Borkowski Emma A, Shaw Richard J, Peregrine Andrew S
Department of Pathobiology, Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, Ontario N1G 2W1, Canada.
Department of Population Medicine, Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, Ontario N1G 2W1, Canada.
Vet Parasitol. 2025 Aug;338:110549. doi: 10.1016/j.vetpar.2025.110549. Epub 2025 Jul 25.
The rate at which pastured lambs develop immunity to gastrointestinal nematodes (GINs) is highly variable and depends on factors such as larval (L) challenge, nutrition, genetics and overall health. Salivary immunoglobulin A (IgA) against carbohydrate larval antigen (CarLA), found on the L epicuticle of GINs, has been shown to be an indicator of immunity to GINs in sheep. This study aimed to measure the salivary anti-CarLA IgA concentrations, considered a moderately heritable trait, of Ontario ewes and their offspring, and examine associations with the health and performance of pastured lambs. In 2022, 98 replacement ewe lambs were randomly selected in Ontario, Canada, following their first grazing season and just prior to breeding. At selection, each ewe lamb had its salivary anti-CarLA IgA concentration, fecal egg count (FEC), and weight measured. In 2023, these ewes were re-sampled 4 weeks after returning to pasture; likewise, offspring lambs (n = 107) were identified and sampled 60 days after grazing began. At sampling, 22.4 % (24/107) of offspring lambs had detectable salivary anti-CarLA IgA. Linear mixed models revealed that the 2022 salivary anti-CarLA IgA concentration in dams was positively associated with offspring weight, when age and sex were controlled (β=0.834; p = 0.008). Additionally, the 2023 salivary anti-CarLA IgA concentrations in dams were negatively associated with the FEC of their pastured offspring (β= -0.191; p = 0.044). These data suggest that acquired immunity to GINs develops early in Ontario lambs, and that salivary anti-CarLA IgA concentration of the dam may predict the performance of offspring when exposed to GINs on pasture.
放牧羔羊对胃肠道线虫（GINs）产生免疫力的速度差异很大，这取决于幼虫（L）感染强度、营养、遗传和整体健康状况等因素。已发现，针对GINs L表皮上碳水化合物幼虫抗原（CarLA）的唾液免疫球蛋白A（IgA）是绵羊对GINs免疫力的一个指标。本研究旨在测量安大略省母羊及其后代唾液中抗CarLA IgA的浓度（这是一个具有中等遗传性的性状），并研究其与放牧羔羊健康和性能的关联。2022年，在加拿大安大略省，98只后备母羊羔羊在经历第一个放牧季节后、配种前被随机挑选出来。挑选时，测量了每只母羊羔羊的唾液抗CarLA IgA浓度、粪便虫卵计数（FEC）和体重。2023年，这些母羊回到牧场4周后再次进行采样；同样，在放牧开始60天后，对后代羔羊（n = 107）进行识别和采样。采样时，22.4%（24/107）的后代羔羊唾液中可检测到抗CarLA IgA。线性混合模型显示，在控制年龄和性别后，2022年母羊唾液抗CarLA IgA浓度与后代体重呈正相关（β = 0.834；p = 0.008）。此外，2023年母羊唾液抗CarLA IgA浓度与放牧后代的FEC呈负相关（β = -0.191；p = 0.044）。这些数据表明，安大略省羔羊对GINs的获得性免疫力在早期就已形成，并且母羊唾液抗CarLA IgA浓度可能预测后代在牧场上接触GINs时的性能。
