Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Integr Zool. 2024 Jul;19(4):585-595. doi: 10.1111/1749-4877.12758. Epub 2023 Aug 8.
Research has shown that leached plant toxins negatively impact the growth and development of larval amphibians. However, tadpoles may encounter these same toxins in food material, and differential exposure routes and distribution of toxic chemicals can yield variable downstream effects on animals. To date, most research understanding the interactions between dietary plant toxins and herbivores has been conducted in terrestrial systems. Despite the abundance of plant toxins in food and water sources, the effects of dietary plant toxins on larval amphibians have not been studied, and tannins could negatively affect these species. Here, green frog tadpoles (Lithobates clamitans) were fed diets with or without 2% tannic acid to test how their growth, development, behavior, and gut microbiome respond to dietary tannins. At the end of the trial, we conducted a behavioral assay to measure tadpole activity and boldness and inventoried the gut microbiome using 16S rRNA sequencing. Dietary tannins significantly decreased body mass by 66% and length by 28%, without influencing tadpole developmental stage. We found significant differences in exploratory behavior and boldness during the first minute of our behavioral assay, demonstrating that tannins have the potential to influence behavior during novel or stressful events. Finally, tannins significantly sculpted the gut microbiome, with an increase in the measurement of Shannon entropy. We observed 7 microbial phyla and 153 microbial genera that exhibited significantly differential abundances differences between control and tannic acid-fed tadpoles. Collectively, our results demonstrate that dietary tannins have the potential to alter amphibian growth, behavior, and microbiome.
研究表明，浸出的植物毒素会对幼体两栖动物的生长和发育产生负面影响。然而，蝌蚪可能会在食物中遇到相同的毒素，并且不同的暴露途径和有毒化学物质的分布可能会对动物产生不同的下游影响。迄今为止，大多数关于植物毒素与食草动物相互作用的研究都是在陆地系统中进行的。尽管食物和水源中含有丰富的植物毒素，但关于饮食中植物毒素对幼体两栖动物的影响尚未得到研究，而单宁可能会对这些物种产生负面影响。在这里，绿蛙蝌蚪（Lithobates clamitans）被喂食含有或不含有 2%单宁酸的饮食，以测试它们的生长、发育、行为和肠道微生物组如何对饮食中的单宁做出反应。在试验结束时，我们进行了一项行为测定，以测量蝌蚪的活动和大胆程度，并使用 16S rRNA 测序对肠道微生物组进行编目。饮食中的单宁酸使蝌蚪的体重减少了 66%，体长减少了 28%，而对蝌蚪的发育阶段没有影响。我们在行为测定的前一分钟发现了探索行为和大胆程度的显著差异，这表明单宁酸有可能影响新的或压力事件期间的行为。最后，单宁酸显著地塑造了肠道微生物组，Shannon 熵的测量值增加。我们观察到 7 个微生物门和 153 个微生物属在对照组和单宁酸喂养组的蝌蚪之间表现出显著的丰度差异。总的来说，我们的结果表明，饮食中的单宁酸有可能改变两栖动物的生长、行为和微生物组。
