Pathogenic infections increase morbidity and reduce performance in livestock, and thus understanding the comprehensive physiological changes associated with infections can benefit production sustainability. In this study, we sought to investigate such physiological responses to an acute immune challenge in lambs. Polypay wethers received single IV injections of 1.5 µg/kg lipopolysaccharide endotoxin (LPS-injected; n = 6) or saline (controls; n = 6). Corneal temperatures (via infrared thermography), rectal temperatures, blood, plasma, and saliva were assessed every 2 hr for 10 hr after injections. Blood was also assessed at 24 hr. LPS-injected lambs exhibited elevated (P < 0.05) corneal and rectal temperatures that peaked at 4 hr but were still slightly greater (P < 0.05) than controls at 10 hr. Circulating total white blood cells, monocytes, and granulocytes were reduced (P < 0.05) in LPS-injected lambs within the first 4 hr but were subsequently greater (P < 0.05) than in controls. Lymphocytes were reduced (P < 0.05) in LPS-injected lambs over the first 8 hr and did not differ from controls thereafter. Red blood cells, hematocrit, and hemoglobin were increased (P < 0.05) in LPS-injected lambs over the first 6 hr, indicating mild dehydration. Blood glucose briefly increased (P < 0.05) in LPS-injected lambs at 2 hr but was less (P < 0.05) than in controls thereafter. Blood lactate was greater (P < 0.05) in LPS-injected lambs between 6 and 10 hr after injections, which together with reduced (P < 0.05) CO2 partial pressure indicated a metabolic shift toward glycolysis. LPS-injected lambs exhibited a transient increase (P < 0.05) in plasma TNFα at 2 and 4 hr only and sustained increases (P < 0.05) in CXCL9 and CXCL10 beginning at 6 and 4 hr, respectively. They also exhibited a mild, paradoxical increase (P < 0.05) in the anti-inflammatory sFRP3. Salivary TNFα was increased (P < 0.05) in LPS-injected lambs at 2 hr only. Regression analyses indicated that rectal temperatures were a generally poor predictor of the other inflammatory components in this study, with the exception of circulating leukocyte populations. Likewise, correlations among the 10 cytokines measured in this study were generally weak, with notable exceptions between CXCL9 and CXCL10 and between IL-21 and IFNγ. These findings demonstrate that physiological changes to even short-lived immune challenges are dynamic in nature and persist beyond the time frame of febrile responses and other common assessments.

中文翻译：

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脂多糖内毒素注射提高了唾液 TNFα 和角膜温度，并诱导了白羊的循环白细胞、炎症细胞因子和代谢指标的动态变化

致病性感染会增加牲畜的发病率并降低生产性能，因此了解与感染相关的综合生理变化有助于生产的可持续性。在这项研究中，我们试图研究羔羊对急性免疫挑战的这种生理反应。Polypay 接受单次静脉注射 1.5 µg/kg 脂多糖内毒素（LPS 注射；n = 6）或生理盐水（对照；n = 6）。注射后每 2 小时评估一次角膜温度（通过红外热成像）、直肠温度、血液、血浆和唾液，持续 10 小时。血液也在 24 小时被评估。注射 LPS 的羔羊表现出升高的 (P < 0.05) 角膜和直肠温度，在 4 小时达到峰值，但在 10 小时仍略高于对照 (P < 0.05)。循环总白细胞，在前 4 小时内，注射 LPS 的羔羊中的单核细胞和粒细胞减少（P < 0.05），但随后比对照组更大（P < 0.05）。在第一个 8 小时内，注射 LPS 的羔羊中的淋巴细胞减少（P＜0.05），此后与对照无差异。在前 6 小时内，注射 LPS 的羔羊的红细胞、血细胞比容和血红蛋白增加（P < 0.05），表明轻度脱水。注射 LPS 的羔羊在 2 小时时血糖短暂升高 (P < 0.05)，但此后低于对照组 (P < 0.05)。注射 LPS 后 6 到 10 小时，注射 LPS 的羔羊的血乳酸更高（P < 0.05），这与降低的（P < 0.05）CO2 分压一起表明代谢向糖酵解转变。注射 LPS 的羔羊仅在 2 小时和 4 小时表现出血浆 TNFα 的短暂增加（P < 0.05），而 CXCL9 和 CXCL10 分别在 6 小时和 4 小时开始持续增加（P < 0.05）。它们还表现出抗炎 sFRP3 的轻度、矛盾的增加 (P < 0.05)。仅在 2 小时时，注射 LPS 的羔羊的唾液 TNFα 增加（P < 0.05）。回归分析表明，除循环白细胞群外，直肠温度通常不能很好地预测本研究中的其他炎症成分。同样，本研究中测量的 10 种细胞因子之间的相关性通常很弱，CXCL9 和 CXCL10 之间以及 IL-21 和 IFNγ 之间有明显的例外。