The modulation of antioxidant responses and onset of oxidative stress is due to several factors, including temperature, diets, and hypoxia followed by re-oxygenation in several aerobic organisms including rotifers. In this context, the aims of this study were (1) to establish a protocol for evaluating in vivo ROS (reactive oxygen species) concentration in rotifer Brachionus plicatilis and (2) to determine the effects on population growth and oxidative stress responses in rotifers fed with different diets: commercial baker’s yeast (Saccharomyces cerevisiae) or concentrated microalgae Nannochloropsis oculata. The rotifers were stocked in five densities (200, 400, 660, 800, and 1000 rotifers mL⁻¹) and exposed to four concentrations of dichlorofluorescein diacetate (H₂DCF-DA) (4.4, 8.7, 17.5, and 35 nmol L⁻¹) to optimize a protocol for in vivo ROS determination. The methodology was standardized using 8.7 nmol H₂DCF-DA L⁻¹ and it is effective when rotifer density lies within 400 and 1000 rotifers mL⁻¹. In the second experiment, rotifers were fed with 55 × 10⁹ microalgae cells or 0.6 g yeast per million rotifers for 4 days in quadruplicate. Rotifers fed with yeast showed poorer oxidative condition as shown by (a) a higher in vivo ROS concentration; (b) a higher GST (glutathione S-transferase) activity; and (3) a reduced total antioxidant capacity. In conclusion, the methodology to measure in vivo ROS concentration using the H₂DCF-DA was efficiently standardized for the first time to rotifers B. plicatilis. Although the yeast-fed rotifers showed higher population growth comparing with this concentration of microalgae, the rotifers fed with N. oculata faced a safer pro-oxidant scenario and presented a higher percentage of egg-carrying females throughout the experiment indicating a better physiological condition.

抗氧化剂反应的调节和氧化应激的发作是由于多种因素引起的，包括温度，饮食和低氧，然后在包括轮虫在内的几种好氧生物中进行再氧化。在这种情况下，这项研究的目的是（1）建立评估轮虫Brachionus plicatilis中体内ROS（活性氧种类）浓度的协议，以及（2）确定对轮虫饲喂的轮虫的种群生长和氧化应激反应的影响不同饮食：商业面包酵母（Saccharomyces cerevisiae）或浓缩微藻Nannochloropsis oculata。轮虫以五种密度投放（200、400、660、800和1000轮虫mL ^-1）并暴露于四种浓度的二乙酸二氯荧光素（H ₂ DCF-DA）（4.4、8.7、17.5和35 nmol L ^-1）以优化体内ROS测定的方案。该方法使用8.7 nmol H ₂ DCF-DA L ^-1进行了标准化，当轮虫密度在400到1000轮虫mL ^-1之间时是有效的。在第二个实验中，轮虫饲喂55×10 ⁹微藻细胞或0.6 g酵母/百万个轮虫，一式四份，共4天。饲喂酵母的轮虫表现出较差的氧化条件，如（a）体内ROS浓度较高；（b）较高的GST（谷胱甘肽S-转移酶）活性；（3）总抗氧化能力降低。总之，首次使用轮虫B. plicatilis有效地标准化了使用H ₂ DCF-DA测量体内ROS浓度的方法。尽管与这种微藻浓度相比，用酵母喂养的轮虫显示出更高的种群增长，但饲喂N. oculata的轮虫面临着更安全的促氧化剂环境，并且在整个实验过程中呈现出更高的带卵雌性比例，表明生理条件更好。