Data from: Maternal allocation of carotenoids increases tolerance to bacterial infection in brown trout

Life-history theory predicts that iteroparous females allocate their resources differently among different breeding seasons depending on their residual reproductive value. In iteroparous salmonids there is typically much variation in egg size, egg number, and in the compounds that females allocate to their clutch. These compounds include various carotenoids whose functions are not sufficiently understood yet. We sampled 37 female and 35 male brown trout from natural streams, collected their gametes for in vitro fertilizations, experimentally produced 185 families in 7 full-factorial breeding blocks, raised the developing embryos singly (n = 2960), and either sham-treated or infected them with Pseudomonas fluorescens. We used female redness (as a measure of carotenoids stored in the skin) and their allocation of carotenoids to clutches to infer maternal strategies. Astaxanthin contents largely determined egg colour. Neither egg weight nor female size was correlated with the content of this carotenoid. However, astaxanthin content was positively correlated with larval growth and with tolerance against P. fluorescens. There was a negative correlation between female skin redness and the carotenoid content of their eggs. Although higher astaxanthin contents in the eggs were associated with an improvement of early fitness-related traits, some females appeared not to maximally support their current offspring as revealed by the negative correlation between female red skin colouration and egg carotenoid content. This correlation was not explained by female size and supports the prediction of a maternal trade-off between current and future reproduction.生活史理论（life-history theory）指出，多次繁殖的雌性（iteroparous females）会依据自身剩余繁殖价值（residual reproductive value），在不同繁殖季间差异化分配资源。对于多次繁殖的鲑科鱼类（salmonids）而言，雌性的卵粒大小、产卵数量以及投入至卵团（clutch）的各类化合物通常存在显著变异。这类化合物包含多种类胡萝卜素（carotenoids），其具体功能目前尚未被充分阐释。本研究从自然溪流中采集了37条雌性褐鳟与35条雄性褐鳟，收集其配子（gametes）用于体外受精（in vitro fertilizations）；通过7个全因子育种组（full-factorial breeding blocks）构建了185个家系，将发育中的胚胎进行单头饲养，总样本量达2960，并分别对胚胎开展假处理或接种荧光假单胞菌（Pseudomonas fluorescens）。本研究以雌性褐鳟的皮肤红度作为其皮肤储存类胡萝卜素的量化指标，结合其向卵团分配的类胡萝卜素水平，推断其母本繁殖策略。虾青素（astaxanthin）含量在很大程度上决定了卵粒的颜色。卵粒重量与雌性个体体型均与该类胡萝卜素的含量无显著相关性。但虾青素含量与幼体生长速率以及对荧光假单胞菌的耐受性呈显著正相关。雌性个体的皮肤红度与其卵粒中的类胡萝卜素含量呈显著负相关。尽管卵粒中较高的虾青素含量与早期适合度相关性状（fitness-related traits）的提升存在关联，但部分雌性似乎并未最大化投入资源至当前繁殖后代——这一现象可通过雌性皮肤红度与卵粒类胡萝卜素含量的负相关关系得到印证。该相关性不受雌性个体体型的影响，这一结果支持了"雌性会在当前繁殖与未来繁殖之间存在繁殖权衡"的理论预测。