Developments of pulmonary diseases, often accompanied by infections of bacteria, severely affect meat production and welfare of pigs. This study investigated 307 pigs at age of 240 days from an eight-breed cross reared under standardized housing conditions for associations among extent of lung lesions, bacteria load inferred from 16S rRNA sequencing of bronchoalveolar lavage fluid, as well as 57 immune cells and 25 hematological traits. We showed that the pigs under study suffered substantial and varied lung lesions, and the Mycoplasma is the most associated bacteria genera. At a false discovery rate of 0.05 (FDR<0.05), severity of lung lesions were significantly associated with greater CD8+ to CD3+ cell ratio, neutrophil-to-lymphocyte ratio (NLR), and standard deviation of red blood cell volume distribution width (RDW-SD), and lower CD4-CD8-/CD3+, CD3+CD4-CD8-/PBMCs (peripheral blood mononuclear cells) and CD14-CD16-/PBMCs cell ratios, mean corpuscular hemoglobin concentration, lymphocyte count and lymphocyte count percentage, reflecting an status of inflammation, immune suppression and hypoxia of the pigs accompanying the progression of lung lesion. The Mycoplasma abundance showed positive correlations with neutrophil count, neutrophil count percentage, NLR, monocyte count , coefficient of variation in red blood cell volume distribution width (RDW-CV), and RDW-SD, and negative correlations with mean corpuscular hemoglobin concentration, lymphocyte count, and lymphocyte count percentage, these correlations are largely consistent with those of lung lesions, supporting the comorbidity of lung lesions and Mycoplasma infection. We also observed nonlinear associations that sharp increases in neutrophil count and neutrophil count percentage occurred only when Mycoplasma abundance raised above the population-average level. The results provide helpful insights into the changes of host immune status in response to Mycoplasma relevant lung diseases in pigs.

中文翻译：

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八支杂交异种猪中支原体负荷和肺部病变对猪免疫和血液学状态的影响。

肺部疾病的发展通常伴随细菌感染，严重影响猪的肉类生产和福利。这项研究调查了307只猪，这些猪是在标准化的饲养条件下饲养的8头杂交的240天大的猪，其相关性涉及肺部病变程度，根据支气管肺泡灌洗液的16S rRNA测序推断的细菌载量以及57个免疫细胞和25个血液特质。我们表明，所研究的猪遭受了实质性和多样的肺部病变，而支原体是最相关的细菌属。在0.05的错误发现率（FDR <0.05）下，肺部病变的严重程度与CD8 +与CD3 +细胞比例，中性白细胞与淋巴细胞比例（NLR）以及红细胞体积分布宽度（RDW）的标准偏差显着相关-SD），较低的CD4-CD8- / CD3 +，CD3 + CD4-CD8- / PBMC（外周血单核细胞）和CD14-CD16- / PBMCs细胞比率，平均红细胞血红蛋白浓度，淋巴细胞计数和淋巴细胞计数百分比，反映了炎症状态，随着肺部病变的发展，猪的免疫抑制和缺氧。支原体丰度与中性粒细胞计数，中性粒细胞计数百分比，NLR，单核细胞计数，红细胞体积分布宽度（RDW-CV）和RDW-SD的变异系数呈正相关，与平均红细胞血红蛋白浓度，淋巴细胞呈负相关计数和淋巴细胞计数百分比，这些相关性在很大程度上与肺部病变相关，支持了肺部病变和支原体感染的合并症。我们还观察到非线性关联，中性粒细胞计数和中性粒细胞计数百分比的急剧增加仅在支原体丰度提高到高于人口平均水平时发生。结果为猪对支原体相关的肺部疾病的宿主免疫状态变化提供了有益的见解。