Parejo-Pulido Daniel, Casquero Silvia, Romero-Haro Ana Á, Pérez-Rodríguez Lorenzo
Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ronda de Toledo 12, 13005, Ciudad Real, Spain.
Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN), CSIC, José Gutiérrez Abascal 2, E-28006 Madrid, Spain.
J Exp Biol. 2025 Jul 9. doi: 10.1242/jeb.250556.
The activation of the immune system in response to a pathogen infection can impose significant costs on growth and oxidative stress. Developing individuals are particularly vulnerable to this challenge, as their physiological systems are still maturing and their rapid growth to achieve an optimal size is resource demanding. Here, we investigated the costs in terms of growth and oxidative stress of an experimentally induced immune challenge in wild spotless starling (Sturnus unicolor) nestlings. To this aim, individuals were injected with a lipopolysaccharide (LPS), an antigen that triggers an immune response, or a control substance (PBS) in a within-brood design. Although the immune activation impaired the rate of body mass gain within the first 6h after the challenge, nestlings subsequently showed an accelerated increase in mass within the following 18h, reaching a similar body mass to the Controls by the next day. This represents a compensation ('catch-up growth') occurring within as little as 6h to 24h after the challenge. Despite this compensation, initially smaller challenged nestlings showed reduced body mass and survival rates by 8 days after treatment compared to smaller Control nestlings. The induced immune challenge also led to increased plasma levels of oxidative damage (reactive oxygen metabolites, ROMs) and antioxidant capacity (OXY), supporting the oxidative cost of immune system activation. These findings highlight the costs of mounting an immune response during early life, characterized by an altered growth dynamic and increased oxidative damage, and the condition-dependence of these effects.
免疫系统对病原体感染的激活会给生长和氧化应激带来巨大代价。发育中的个体尤其容易受到这一挑战的影响，因为它们的生理系统仍在成熟，且为达到最佳体型的快速生长需要消耗大量资源。在此，我们研究了野生纯色椋鸟（Sturnus unicolor）雏鸟在实验诱导的免疫挑战中，生长和氧化应激方面的代价。为此，我们采用巢内设计，给个体注射脂多糖（LPS，一种触发免疫反应的抗原）或对照物质（PBS）。尽管免疫激活在挑战后的前6小时内损害了体重增加率，但雏鸟随后在接下来的18小时内体重加速增加，到第二天达到与对照组相似的体重。这代表了在挑战后短短6小时至24小时内出现的一种补偿（“追赶生长”）。尽管有这种补偿，但与较小的对照雏鸟相比，最初较小的受挑战雏鸟在处理后8天体重和存活率降低。诱导的免疫挑战还导致血浆氧化损伤水平（活性氧代谢产物，ROMs）和抗氧化能力（OXY）增加，这支持了免疫系统激活的氧化代价。这些发现突出了生命早期产生免疫反应的代价，其特征是生长动态改变和氧化损伤增加，以及这些影响的条件依赖性。
