Fish Pathology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain.
Nutrigenomics and Fish Endocrinology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Castellón, Spain.
Microbiome. 2020 Nov 23;8(1):168. doi: 10.1186/s40168-020-00922-w.
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. Video Abstract.
肠道微生物群在动物健康方面的关键作用，促使人们越来越有兴趣操纵这些细菌群体，以改善动物福利。水产养殖领域也不例外，在过去的几年中，许多研究已经描述了不同鱼类物种的这些群体。然而，这并非易事，因为肠道微生物群由非常动态的群体组成，这些群体受到饮食、环境、宿主年龄和遗传等不同因素的影响。在本研究中，我们旨在确定金头鲷（Sparus aurata）的遗传背景是否会影响肠道微生物组成，这些细菌群体如何通过饮食变化来调节，以及生长选择对肠道疾病抵抗力的影响。为此，我们选择了三代金头鲷的五个家族，这些家族在两代中分别进行了快速、中速和慢速生长的选择（F3 代），然后将它们一起饲养在相同的开放式流水池中，在 9 个月的时间里分别投喂对照或平衡的植物性饮食。每个家族和饮食处理的 6 条鱼被处死，从前肠部分附着的细菌进行测序。同时，快速生长组和慢速生长组的鱼感染了肠道寄生虫 Enteromyxum leei，并评估了疾病症状、流行率、强度和寄生虫丰度。
家族间的 alpha 多样性指标没有差异，核心细菌结构是金头鲷肠道微生物群的典型组成，表明任何一组都没有出现肠道微生物失调。植物性饮食显著改变了中速和慢速生长家族的微生物群，对快速生长组的影响较小。有趣的是，与其他家族相比，快速生长家族检测到的较小变化可能在代谢水平上产生了更多的变化。在寄生虫感染后，快速生长组的疾病症状和寄生虫强度及丰度明显低于慢速生长组。
这些结果表明存在明显的基因组-微生物组相互作用，表明快速生长的家族拥有一种在饮食变化时更具弹性的微生物群。这些动物也表现出更好的应对肠道感染的能力。
