Department of Zoology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia.
School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA.
Naturwissenschaften. 2021 Jan 5;108(1):4. doi: 10.1007/s00114-020-01715-9.
Artificial light at night (ALAN) exposes animals to a novel environmental stimulus, one that is generally thought to be maladaptive. ALAN-related health problems have received little attention in non-model species, and we generally know little about the nutritional-physiological impacts of ALAN, especially in young animals. Here, we use a novel application of the acid steatocrit method to experimentally assess changes in digestive efficiency of growing king quail (Excalfactoria chinensis) in response to ALAN. Two weeks after hatching, quail were split into two groups (n = 20-21 per group): overnight-light-treated vs. overnight-dark-treated. When the chicks were 3 weeks old, the experimental group was exposed to weak blue light (ca. 0.3 lux) throughout the entire night for 6 consecutive weeks, until all the chicks had achieved sexual maturation. Fecal samples for assessing digestive efficiency were collected every week. We found that digestive efficiency of quail was reduced by ALAN at two time points from weeks 4 to 9 after hatching (quail reach adulthood by week 9). The negative effect of ALAN on digestion coincided with the period of fastest skeletal growth, which suggests that ALAN may reduce digestive efficiency when energetic demands of growth are at their highest. Interestingly, growth rate was not influenced by ALAN. This suggests that either the negative physiological impacts of ALAN may be concealed when food is provided ad libitum, the observed changes in digestive efficiency were too small to affect growth or condition, or that ALAN-exposed birds had reduced energy expenditure. Our results illustrate that the health impacts of ALAN on wild animals should not be restricted to traditional markers like body mass or growth rate, but instead on a wide array of integrated physiological traits.
人工夜间光照（ALAN）使动物暴露于一种新的环境刺激下，通常认为这是一种适应不良的刺激。在非模式物种中，与 ALAN 相关的健康问题尚未得到关注，我们对 ALAN 的营养生理影响知之甚少，尤其是在幼小动物中。在这里，我们使用一种新颖的酸脂滴比浊法来实验性地评估生长中的鹌鹑（Excalfactoria chinensis）对 ALAN 的消化效率变化。在孵化后两周，鹌鹑被分为两组（每组 20-21 只）：夜间光照处理组和夜间黑暗处理组。当小鸡 3 周大时，实验组在整个晚上暴露于微弱的蓝光（约 0.3 勒克斯）下，连续 6 周，直到所有小鸡都达到性成熟。每周收集粪便样本以评估消化效率。我们发现，在孵化后 4 至 9 周（鹌鹑在第 9 周达到成年）期间，ALAN 降低了鹌鹑的消化效率。ALAN 对消化的负面影响与骨骼生长最快的时期相吻合，这表明当生长的能量需求达到最高时，ALAN 可能会降低消化效率。有趣的是，ALAN 对生长速度没有影响。这表明，当提供自由采食时，ALAN 的负面影响可能被掩盖；或者观察到的消化效率变化太小，不会影响生长或身体状况；或者 ALAN 暴露的鸟类的能量消耗减少。我们的研究结果表明，ALAN 对野生动物的健康影响不应仅限于体重或生长速度等传统指标，而应包括广泛的综合生理特征。
