The key effects of intestinal microbiota in animal health have led to an increasing interest in manipulating these bacterial populations to improve animal welfare. The aquaculture sector is no exception and in the last years, many studies have described these populations in different fish species. However, this is not an easy task, as intestinal microbiota is composed of very dynamic populations that are influenced by different factors, such as diet, environment, host age, and genetics. In the current study, we aimed to determine whether the genetic background of gilthead sea bream (Sparus aurata) influences the intestinal microbial composition, how these bacterial populations are modulated by dietary changes, and the effect of selection by growth on intestinal disease resistance. To that aim, three different groups of five families of gilthead sea bream that were selected during two generations for fast, intermediate, or slow growth (F3 generation) were kept together in the same open-flow tanks and fed a control or a well-balanced plant-based diet during 9 months. Six animals per family and dietary treatment were sacrificed and the adherent bacteria from the anterior intestinal portion were sequenced. In parallel, fish of the fast- and slow-growth groups were infected with the intestinal parasite Enteromyxum leei and the disease signs, prevalence, intensity, and parasite abundance were evaluated. No differences were detected in alpha diversity indexes among families, and the core bacterial architecture was the prototypical composition of gilthead sea bream intestinal microbiota, indicating no dysbiosis in any of the groups. The plant-based diet significantly changed the microbiota in the intermediate- and slow-growth families, with a much lower effect on the fast-growth group. Interestingly, the smaller changes detected in the fast-growth families potentially accounted for more changes at the metabolic level when compared with the other families. Upon parasitic infection, the fast-growth group showed significantly lower disease signs and parasite intensity and abundance than the slow-growth animals. These results show a clear genome-metagenome interaction indicating that the fast-growth families harbor a microbiota that is more flexible upon dietary changes. These animals also showed a better ability to cope with intestinal infections.

中文翻译：

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生长的遗传选择驱动着金头鲷的肠道菌群组成和寄生虫抗病性的差异

肠道菌群在动物健康中的关键作用已引起人们对操纵这些细菌种群以改善动物福利的兴趣日益增加。水产养殖部门也不例外，最近几年，许多研究已经描述了这些鱼类在不同鱼类中的种群。但是，这并不是一件容易的事，因为肠道菌群由非常活跃的种群组成，这些种群受饮食，环境，宿主年龄和遗传学等不同因素的影响。在当前的研究中，我们旨在确定银头鲷的遗传背景是否会影响肠道微生物组成，饮食变化如何调节这些细菌种群以及生长选择对肠道疾病抗性的影响。为此，在两个世代中为快速，中度或缓慢生长（F3代）选择的三个不同类别的金头鲷科的五个不同的家庭，一起放在同一个敞口水箱中，并饲喂以对照或平衡良好的植物为基础在9个月内饮食。每个家庭和饮食处理处死六只动物，并对来自前肠部分的附着细菌进行测序。同时，快生长和慢生长组的鱼被肠道寄生虫李氏肠杆菌感染，并评估其病征，患病率，强度和寄生虫丰度。在家庭之间没有发现α多样性指数的差异，核心细菌结构是金头鲷的肠道微生物群的原型组成，表明任何一组都没有营养不良。以植物为基础的饮食显着改变了中速增长和慢速增长家庭的微生物群，而对快速增长的家庭的影响要小得多。有趣的是，与其他家庭相比，在快速增长的家庭中检测到的较小变化可能在代谢水平上造成了更多变化。受到寄生虫感染后，与缓慢生长的动物相比，快速生长的动物显示出明显更低的疾病体征，寄生虫强度和丰度。这些结果显示出清晰的基因组-基因组交互作用，表明快速增长的家庭拥有一个微生物群，随着饮食的变化，微生物群更加灵活。这些动物还表现出更好的应对肠道感染的能力。对快速增长群体的影响要小得多。有趣的是，与其他家庭相比，在快速增长的家庭中检测到的较小变化可能在代谢水平上造成了更多变化。受到寄生虫感染后，与缓慢生长的动物相比，快速生长的动物显示出明显更低的疾病体征，寄生虫强度和丰度。这些结果显示出清晰的基因组-基因组交互作用，表明快速增长的家庭拥有一个微生物群，随着饮食的变化，微生物群更加灵活。这些动物还表现出更好的应对肠道感染的能力。对快速增长群体的影响要小得多。有趣的是，与其他家庭相比，在快速增长的家庭中检测到的较小变化可能在代谢水平上造成了更多变化。受到寄生虫感染后，与缓慢生长的动物相比，快速生长的动物显示出明显更低的疾病体征，寄生虫强度和丰度。这些结果显示出清晰的基因组-基因组交互作用，表明快速增长的家庭拥有一个微生物群，随着饮食的变化，微生物群更加灵活。这些动物还表现出更好的应对肠道感染的能力。快生长组的疾病迹象，寄生虫强度和丰度明显低于慢增长动物。这些结果显示出清晰的基因组-基因组交互作用，表明快速增长的家庭拥有一个微生物群，随着饮食的变化，微生物群更加灵活。这些动物还表现出更好的应对肠道感染的能力。快生长组的疾病迹象，寄生虫强度和丰度明显低于慢增长动物。这些结果显示出清晰的基因组-基因组交互作用，表明快速增长的家庭拥有一个微生物群，随着饮食的变化，微生物群更加灵活。这些动物还表现出更好的应对肠道感染的能力。