Biada Iliyass, Tiezzi Francesco, Ibáñez-Escriche Noelia, García María Luz, Argente María José, Santacreu María Antonia
Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, València, Spain.
Dipartimento di Scienze e Tecnologie Agrarie, Alimentari, Ambientali e Forestali, Università degli Studi di Firenze, Firenze, Italy.
J Anim Sci. 2025 Jan 4;103. doi: 10.1093/jas/skaf206.
Heat stress affects livestock productivity and health, particularly in rabbits, due to their physiological vulnerabilities. This study explores the relationship between environmental conditions, genetic lines backgrounds, and soft fecal microbiota. A 2 × 2 factorial design was used, involving 2 maternal rabbit lines: A (standard longevity line) and LP (high longevity line), exposed to heat stress and thermal comfort. Samples were analyzed with multiple models to assess the impact of heat stress on microbiota by comparing microbial diversity and evaluating the classification performance of Random Forest, Partial Least Squares Discriminant Analysis (PLS-DA), and Bayesian Regression (BayesC). Heat stress influenced microbial diversity in both lines, increasing alpha diversity and driving significant beta-diversity shifts (2.3% variance, P < 0.001). This could be due to intestinal barrier disruption, which facilitate pathogen proliferation. The high longevity line LP exhibited higher richness under thermal comfort, whereas heat stress equalized these differences between lines, possibly due to increased pathogen proliferation in the low longevity line A. These differences in response to heat stress may be influenced by the crosstalk between microbiota and host genetics, shaping distinct adaptive mechanisms in each line. Prediction accuracy and key selected variables distinguishing between lines A and LP varied across thermal conditions, with the area under the curve exceeding 0.92 under heat stress and 0.87 in thermal comfort. This reflects different microbiome regulations between the 2 lines under heat stress. Potential stress-associated taxa such as Erysipelatoclostridium and Monoglobus were more abundant in the low longevity line A. These results highlight LP's higher longevity and expected resilience, while line A's susceptibility is reflected in a higher abundance of heat stress-associated taxa in the latter. This underscores soft fecal microbiota as a potential biomarker for heat stress resilience and emphasizes the role of host-microbiota interactions in mediating genetic-environmental responses. Additionally, this study highlights the value of combining modeling approaches, which enhance accuracy and reveal key taxa driving heat stress responses. Among the models tested, PLS-DA achieved the highest accuracy, while Random Forest identified a smaller yet biologically relevant subset of taxa, providing valuable phylogenetic and taxonomic insights.
热应激会影响家畜的生产力和健康，尤其是兔子，因为它们生理上较为脆弱。本研究探讨了环境条件、遗传品系背景与软粪微生物群之间的关系。采用了2×2析因设计，涉及2个母兔品系：A（标准长寿品系）和LP（高长寿品系），使其分别处于热应激和热舒适环境中。通过多种模型对样本进行分析，通过比较微生物多样性并评估随机森林、偏最小二乘判别分析（PLS-DA）和贝叶斯回归（BayesC）的分类性能，来评估热应激对微生物群的影响。热应激影响了两个品系的微生物多样性，增加了α多样性并导致显著的β多样性变化（方差为2.3%，P<0.001）。这可能是由于肠道屏障破坏，促进了病原体的增殖。高长寿品系LP在热舒适条件下表现出更高的丰富度，而热应激使品系间的这些差异趋于平衡，这可能是由于低长寿品系A中病原体增殖增加所致。这些对热应激反应的差异可能受到微生物群与宿主遗传学之间相互作用的影响，从而在每个品系中形成不同的适应性机制。区分A品系和LP品系的预测准确性和关键选择变量在不同热条件下有所不同，热应激下曲线下面积超过0.92，热舒适条件下为0.87。这反映了热应激下两个品系之间不同的微生物群调控情况。低长寿品系A中与潜在应激相关的分类群，如丹毒梭菌属和单球属更为丰富。这些结果突出了LP品系更高的长寿性和预期的恢复力，而品系A的易感性体现在后者中与热应激相关分类群的丰度更高。这强调了软粪微生物群作为热应激恢复力潜在生物标志物的作用，并强调了宿主-微生物群相互作用在介导遗传-环境反应中的作用。此外，本研究突出了结合建模方法的价值，这些方法提高了准确性并揭示了驱动热应激反应的关键分类群。在所测试的模型中，PLS-DA达到了最高的准确性，而随机森林识别出了一个较小但具有生物学相关性的分类群子集，提供了有价值的系统发育和分类学见解。
