Reinke Beth A, Erritouni Yasmeen, Calsbeek Ryan
Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA.
Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2018 Apr;218:56-62. doi: 10.1016/j.cbpa.2018.01.014. Epub 2018 Feb 2.
The maternal allocation of carotenoids to eggs has been widely documented and manipulated. However, it is often assumed that the sole adaptive value of this allocation is to increase offspring fitness. Because carotenoids can be pro-oxidants or antioxidants depending on their concentrations and their chemical environment (i.e. presence of other antioxidants), dams may need to dispose of excess carotenoids upon depletion of other antioxidants to prevent oxidative damage. Additionally, the amount of carotenoids deposited in eggs may be dependent on male traits such as quality and coloration. We evaluated these two non-mutually exclusive hypotheses for carotenoid allocation to eggs and assessed paternal effects by supplementing male and female brown anole lizards, Anolis sagrei, with dietary carotenoids or with a combination of carotenoids and vitamin C. We found significant differences in the antioxidant capacities of fertilized and unfertilized eggs produced by female lizards, but the treatment did not affect the antioxidant capacity or carotenoid content of eggs. However, the carotenoid concentration of unfertilized eggs from carotenoid-supplemented females was significantly higher than eggs from the control group. Male coloration and body size did not affect the antioxidant capacity or carotenoid content of the eggs. Carotenoids may be allocated to unfertilized eggs to offset oxidative damage to the dam, with a neutral effect on offspring, rather than to solely provide antioxidant benefits to offspring as has been widely assumed.
母体向卵中分配类胡萝卜素的现象已得到广泛记载和研究。然而，人们通常认为这种分配的唯一适应性价值是提高后代的适应性。由于类胡萝卜素根据其浓度和化学环境（即其他抗氧化剂的存在情况）既可以是促氧化剂也可以是抗氧化剂，所以在其他抗氧化剂耗尽时，母体可能需要处理多余的类胡萝卜素以防止氧化损伤。此外，沉积在卵中的类胡萝卜素数量可能取决于雄性特征，如质量和体色。我们评估了这两种并非相互排斥的关于向卵中分配类胡萝卜素的假说，并通过给雄性和雌性沙氏变色蜥（Anolis sagrei）补充膳食类胡萝卜素或类胡萝卜素与维生素C的组合来评估父本效应。我们发现雌性蜥蜴所产受精卵和未受精卵的抗氧化能力存在显著差异，但处理并未影响卵的抗氧化能力或类胡萝卜素含量。然而，补充类胡萝卜素的雌性所产未受精卵的类胡萝卜素浓度显著高于对照组的卵。雄性的体色和体型并未影响卵的抗氧化能力或类胡萝卜素含量。类胡萝卜素可能被分配到未受精卵中以抵消对母体的氧化损伤，对后代产生中性影响，而不是像人们普遍认为的那样仅仅为后代提供抗氧化益处。
