Ifremer, UMR LEMAR 6539 (CNRS/UBO/Ifremer/IRD), Technopôle de Brest-Iroise, 29280 Plouzané, France
Ifremer, UMR LEMAR 6539 (CNRS/UBO/Ifremer/IRD), Technopôle de Brest-Iroise, 29280 Plouzané, France.
J Exp Biol. 2019 Sep 9;222(Pt 17):jeb210534. doi: 10.1242/jeb.210534.
Food provisioning influences disease risk and outcome in animal populations in two ways. On the one hand, unrestricted food supply improves the physiological condition of the host and lowers its susceptibility to infectious disease, reflecting a trade-off between immunity and other fitness-related functions. On the other hand, food scarcity limits the resources available to the pathogen and slows the growth and metabolism of the host on which the pathogen depends to proliferate. Here, we investigated how food availability, growth rate and energetic reserves drive the outcome of a viral disease affecting an ecologically relevant model host, the Pacific oyster, We selected fast- and slow-growing animals, and we exposed them to high and low food rations. We evaluated their energetic reserves, challenged them with a pathogenic virus, monitored daily survival and developed a mortality risk model. Although high food levels and oyster growth were associated with a higher risk of mortality, energy reserves were associated with a lower risk. Food availability acts both as an enabling factor for mortality by increasing oyster growth and as a limiting factor by increasing their energy reserves. This study clarifies how food resources have an impact on susceptibility to disease and indicates how the host's physiological condition could mitigate epidemics. Practically, we suggest that growth should be optimized rather than maximized, considering that trade-offs occur with disease resistance or tolerance.
食物供应以两种方式影响动物种群的疾病风险和结果。一方面，无限制的食物供应改善了宿主的生理状况，降低了其感染疾病的易感性，反映了免疫与其他与健康相关的功能之间的权衡。另一方面，食物短缺限制了病原体可利用的资源，并减缓了宿主的生长和代谢，而病原体依赖宿主来繁殖。在这里，我们研究了食物供应、生长速度和能量储备如何影响一种影响生态相关模型宿主太平洋牡蛎的病毒疾病的结果。我们选择了生长速度快和慢的动物，并将它们暴露在高和低的食物配给下。我们评估了它们的能量储备，用致病性病毒对它们进行了挑战，每天监测它们的存活率，并开发了一种死亡率风险模型。尽管高食物水平和牡蛎生长与更高的死亡率风险相关，但能量储备与更低的死亡率风险相关。食物供应既是通过增加牡蛎生长来增加死亡率的促进因素，也是通过增加能量储备来限制死亡率的因素。本研究阐明了食物资源如何影响对疾病的易感性，并指出了宿主的生理状况如何减轻流行病。实际上，我们建议在考虑到与疾病抵抗力或耐受性的权衡时，应该优化而不是最大化生长。
